2001 Cobra questions

Sounds very odd - first thing's first (and don't mean to sound insulting), but does it have the factory Hpipe with catalytic converters on it still or does the exhaust system have an offroad midpipe instead?

If it does have an aftermarket exhaust system, which components have been swapped out? Headers? X or H pipe? Does the X or H pipe have cats on it or is it straight piped (ie -offroad) ? Catback system as well (shouldn't make a difference for sniffer testing) ?


Do you know if the car's computer/PCM has been chipped or came with an aftermarket tune when you bought it from the previous owner ? Or was it from a dealer who had no history about the car's mods?



Secondly, who is the "they" doing the work on your car - is it a state inspection shop, Ford dealership, or a hot rod / performance shop?

Not overly familiar with emissions testing since MI does not have it at the state level...but if the car has a factory H-pipe on it and "they" have replaced all of those items, it sounds VERY odd that it still cannot pass the sniffer test - sounds like the shop might be taking you for a ride by replacing ALL of those items (no doubt that's easily over a grand worth of parts already - hate to see the labor rate for all of that work).


I'd get a second opinion or try a different test shop ?

problem

what are the codes? than and now


the pcm is very smart...you might have a code for a bad fuse for o2 heater,,code for o2 hooked up backwards......start with that for better replys

cobra

lhillebrand said:

Supposedly 02 sensor codes, and also they told us it was running rich from the fuel injectors. So they replaced the fuel injectors.

Click to expand...

well i have re read this post 3 times..sounds like we are speaking with the wife to be...hope im right..

if car is at ford dealer now they should find the problem,but who is footing the bill?

cobra90gt gave the best advice...I'd get a second opinion or try a different test shop ?

if by chance you do get stuck with the car with problem,,come back you will get alot of help here

cobra

lhillebrand said:

yes this is the wife to be. i'm sorry i keep repeating myself, i don't really know too much about his car. Just what he tells me and what the dealer is telling us. The used car dealership is paying the bills. They are now rechecking everything and telling him it is still running rich. They still have yet to take it to a ford dealership. Thank you both for all of your help

Click to expand...

fords not cheap...

best i can do is answer to code numbers...

the o2 sensors have alot of fuctions...there are around 20 different codes for them...each of them will tell what sensor sent the signal,and what the signal was for....

than the fun begins...

you will need to find out what codes are being sent from the start and during the work

the pcm is like a wife ,,its always right....the codes are what she is saying

The Ford stealership will figure it out.

cobra

these are the basic tests from ford manual on o2 sensors
each test is for a cause for the code...


2003 PCED OBD SECTION 5: Pinpoint Tests
Procedure revision date: 07/01/2003

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H: Fuel Control H: Introduction

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H20 PERFORM KOER SELF-TEST
Key on, engine running and engine at operating temperature.
Activate Key On, Engine Running (KOER) Self-Test.
Is DTC P0040, P0041, P1127, P1128, P1129 or P2278 present during KOER Self-Test?
Yes No
GO to Section 4, Powertrain Diagnostic Trouble Code (DTC) Charts and SERVICE DTC P0040, P0041, P1127, P1128, P1129 or P2278. GO to H21 .

H21 DIAGNOSTIC TROUBLE CODE (DTC) P0133 AND P0153: HO2S RESPONSE TEST
DTC/HO2S Reference List:

DTC P0133 = HO2S-11
DTC P0153 = HO2S-21
Key on, engine off.
Select Generic OBD II Function from the menu and trigger.
Press Continue.
Select Diagnostic Monitoring Test Results from the menu and trigger.
Scroll to Test ID: 01 trigger and press start.
Key off. (REFER to Section 2 Diagnostic Monitoring Test Results.)
Is the indicated value greater than the minimum threshold?
Yes No
COMPLETE PCM Reset to clear DTCs. COMPLETE HO2S Monitor Drive Cycle (REFER to Section 2, Drive Cycles ). GO to H20 . If test results indicate a pass, testing is complete. GO to H23 .

H23 CHECK FOR UNMETERED AIR LEAKS
Fuel calculations can be affected by unmetered air leaks.

Carefully inspect the following areas for potential air leaks:
Hoses connecting to MAF sensor assembly.
Hoses connecting to throttle body.
Intake manifold gasket leaks.
PCV disconnected.
Vacuum lines disconnected.
Improperly seated engine oil dipstick, tube, and oil fill cap.
Exhaust leaks at flanges and gaskets.
Are any air leaks present?
Yes No
REPAIR source of air leak. COMPLETE PCM Reset to clear DTCs. COMPLETE HO2S Monitor Drive Cycle (REFER to Section 2, Drive Cycles ). GO to H24 .

H24 CHECK HO2S CIRCUIT WIRING
Note: Refer to the PCM connector pin number in the beginning of this pinpoint test.

Disconnect suspect HO2S.
Check for water contamination.
Jumper HO2S signal to VPWR at the HO2S harness connector.
Key on, engine off.
Note: HO2S displayed as O2S on Scan Tool.

Access the correct HO2S PID.
Note: If viewing the HO2S11 (O2S11) PID on the 2.3L Focus, the engine must be running.

Is the voltage greater than 1.50 volts?
Yes No
KEY OFF. REPLACE HO2S. CHANGE oil/filter. COMPLETE PCM Reset to clear DTCs. COMPLETE HO2S Monitor Drive Cycle (REFER to Section 2, Drive Cycles ). KEY OFF. REMOVE jumper wire. GO to H25 .

H25 CHECK HO2S SIGNAL AND SIGNAL RETURN CIRCUITS FOR OPEN IN HARNESS
Note: Refer to the PCM harness connector pin numbers in the beginning of this pinpoint test.

Note: On some applications, a vehicle hoist is required to access the HO2S harness.

Visually inspect the HO2S circuit for exposed wiring, water contamination, corrosion and proper assembly.
Disconnect PCM.
Measure resistance of HO2S SIG circuit between PCM harness connector pin and HO2S harness connector.
Measure resistance of HO2S SIG RTN circuit between PCM harness connector pin and HO2S harness connector.
Is the resistance less than 5.0 ohms?
Yes No
GO to H26 . REPAIR open circuit. COMPLETE HO2S Monitor Drive Cycle (REFER to Section 2, Drive Cycles ).

H26 CHECK HO2S CIRCUIT FOR SHORT TO VPWR IN HARNESS
Measure resistance between the HO2S SIG and VPWR circuit at the PCM harness connector pin.
Is the resistance greater than 10,000 ohms?
Yes No
GO to H27 . GO to H28 .

H27 CHECK FOR SOURCE OF POTENTIAL HO2S CONTAMINATION
Investigate the following items as potential sources of HO2S contamination:
Use of unapproved silicon sealers.
Fuel contaminated by silicon additives.
Excessive oil burning (i.e. rings, valve seals and oil overfill).
Glycol (antifreeze) leaking internally in the engine.
Lead contaminated fuel.
Short drive cycles in cold weather.
Use of unapproved cleaning agents.
Were any of the above conditions or concerns found during inspection?
Yes No
REPAIR source of contamination. REPLACE HO2S and oil/filter. COMPLETE PCM Reset to clear DTCs. COMPLETE HO2S Monitor Drive Cycle (REFER to Section 2, Drive Cycles ). If diagnosing DTC P0141 or P0161, GO to H30 . All others: REPLACE PCM.

H28 VERIFY WIRING IS IN PROPER PIN LOCATION
Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

Measure resistance of the HO2S SIG circuit and HO2S Signal Return circuit between the PCM harness connector pin and the HO2S harness connector.
Is the resistance less than 5.0 ohms?
Yes No
REPLACE HO2S. REPAIR as necessary.

H30 DTCS P0135 AND P0155, P0141 AND P0161: HO2S HEATER CIRCUIT IS SHORTED TO GROUND, SHORTED TO VPWR OR OPEN CIRCUIT.
Note: Refer to the PCM harness connector pin numbers in the beginning of this pinpoint test.

DTC/HO2S Reference List:

DTC P0135 = HO2S HTR-11
DTC P0155 = HO2S HTR-21
DTC P0141 = HO2S HTR-12
DTC P0161 = HO2S HTR-22
DTC P0147 = HO2S HTR-13
DTC P0167 = HO2S HTR-23
If PCM was disconnected during a previous Pinpoint Test, reconnect PCM now.
Note: On some applications, a vehicle hoist is required to access the HO2S harness.

Visually inspect the HO2S circuit for exposed wiring, water contamination, corrosion and proper assembly.
Were any concerns found during inspection?
Yes No
REPAIR any concerns found during inspection. GO to H31 .

H31 PERFORM KEY ON ENGINE OFF (KOEO) SELF-TEST
Key on, engine off.
Perform KOEO Self-Test.
Are any of the following DTCs present: P0135, P0141, P0147, P0155, P0161, P0167?
Yes No
KEY OFF. GO to H32 . KEY OFF. GO to H33 .

H32 CHECK VPWR VOLTAGE TO H02S HARNESS CONNECTOR
Note: If DTCs P0135 and P0155, P0141 and P0161 or P0147 and P0167 are displayed, both heater circuits will require testing. DTCs displayed separately are to be tested individually.

Disconnect the appropriate HO2S(s).
Key on, engine off.
Measure voltage between VPWR and SIG RTN circuits at the HO2S harness connector.
Is the voltage greater than 10.5 volts?
Yes No
KEY OFF. GO to H33 . CHECK fuse in circuit. If fuse is OK, REPAIR open VPWR or SIG RTN circuit.

For no VPWR on LS6, LS8 and Thunderbird:

GO to B5 .

H33 CHECK HO2S HEATER CIRCUIT FOR SHORT TO VPWR AND GND
Disconnect PCM.
Measure resistance between the suspect HO2S HTR circuit and PWR GND circuit.
Measure resistance between the suspect HO2S HTR circuit and SIG RTN circuit at the HO2S harness connector.
Measure resistance between the suspect HO2S HTR circuit and VPWR circuit at the HO2S harness connector.
Is each resistance greater than 10,000 ohms?
Yes No
GO to H34 . REPAIR shorted circuit.

H34 CHECK HO2S HTR CIRCUIT FOR OPEN IN HARNESS
Measure resistance of the suspect HO2S HTR circuit between PCM harness connector pin and HO2S harness connector.
Is the resistance less than 5.0 ohms?
Yes No
GO to H35 . REPAIR open or excessive resistance in the heater circuit in harness.

H35 CHECK HO2S HTR RESISTANCE
Measure the resistance between HO2S HTR pin and VPWR pin at the HO2S connector (refer to schematic at the beginning of this Pinpoint Test).
Is the resistance between 3 and 30 ohms?
Yes No
GO to H36 . REPLACE HO2S.

H36 CHECK HO2S CASE FOR SHORT TO VPWR, HTR AND SIG RTN
Measure resistance between HO2S HTR pin at HO2S connector and the HO2S case.
Measure resistance between the HO2S HTR pin and the SIG RTN Pin at the HO2S sensor.
Is the resistance greater than 10,000 ohms?
Yes No
REPLACE PCM(refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ). REPLACE HO2S.

H40 DTCs P1131, P1132, P1151, P1152, P2195, P2196, P2197 AND P2198: UPSTREAM HO2S NOT SWITCHING.
Note: It is necessary to address all Continuous Memory Ignition and Misfire DTCs, if received during Continuous Memory testing, before addressing any KOER HO2S DTCs.

DTC/HO2S Reference List:

HO2S-11 = DTCs P1131, P1132, P2195 and P2196
HO2S-21 = DTCs P1151, P1152, P2197 and P2198
Check intake air system for leaks, obstructions and damage.
Check air cleaner element, air cleaner housing for blockage.
Verify integrity of the PCV system.
Check for vacuum leaks.
Were any concerns found during inspection?
Yes No
REPAIR as necessary. GO to DC25 .

H41 DTCs P0171, P0172, P0174 AND P0175: FUEL SYSTEM AT THE CORRECTED FUEL TRIM
Note: It is necessary to address all Continuous Memory Ignition and Misfire DTCs, if received during Continuous Memory testing, before addressing any Fuel Trim DTCs.

Fuel System DTC Reference List:

Bank 1 = DTCs P0171 (lean) and P0172 (rich)
Bank 2 = DTCs P0174 (lean) and P0175 (rich)
Check intake air system for leaks, obstructions and damage.
Check air cleaner element, air cleaner housing for blockage.
Verify integrity of the PCV system.
Check fuel delivery system and filter for restriction.
Check for vacuum leaks.
Were any concerns found during inspection?
Yes No
REPAIR as necessary. COMPLETE KAM Reset. GO to DC25 .

H42 PERFORM KOER SELF-TEST
Disconnect fuel vapor hose from intake manifold and plug fitting at intake manifold.
Start engine and run at 2000 rpm for 5 minutes and return to idle.
Complete Key On Engine Running (KOER) Self-Test.
Are any HO2S DTCs P0040, P0041, P1127, P1128, P1129, P1131, P1132, P1151, P1152, P2195, P2196, P2197 or P2198 present?
Yes No
KEY OFF. If DTC P0040, P0041, P1127, P1128 or P1129 is present, GO to Section 4, Powertrain Diagnostic Trouble Code (DTC) Charts and REPAIR those DTCs first.

DTCs (P1131, P2195) or (P1151, P2197):

GO to H43 .

DTCs (P1132, P2196) or (P1152, P2198):

GO to H49 . KEY OFF. For Continuous Memory DTCs Only P0171, P0174, P0172 and P0175:

GO to H52 .

If DTC(s) P1132, P2196and/or P1152, P2198 are no longer present, RECONNECT fuel vapor line.

Vehicles experiencing KOER DTC P1131, P1132, P1151, P1152, P2195, P2196, P2197 or P2198: REFER to Evaporative Emissions, Section 303-13 in the Workshop Manual for system leakage.

All others without recurring DTCs:

Unable to duplicate or identify fault at this time. GO to Z1 .

H43 HO2S CIRCUIT TEST (WITH LEAN DTCs)
Disconnect the HO2S related to the DTC.
Key on, engine off.
Access the correct HO2S PID.
Note: If arcing occurs (indicating a short), remove jumper and GO to H47 (check fuse in the heater circuit).

Jumper the HO2S SIG circuit to the VPWR circuit at the HO2S vehicle harness connector.
Note: If viewing the HO2S11 (O2S11) PID on the 2.3L Focus, the engine must be running.

Is the reading 1.30 volts or greater?
Yes No
KEY OFF. CHECK SIG RTN circuit. GO to H44 . KEY OFF. GO to H46 .

H44 CHECK SIGNAL RETURN CIRCUIT FOR OPEN
Measure resistance of HO2S SIG RTN circuit between the HO2S harness connector and the battery negative post.
Is the resistance reading less than 5.0 ohms?
Yes No
Reconnect HO2S, GO to H52 . GO to H45 .

H45 CHECK HO2S SIGNAL RETURN CIRCUIT FOR OPEN IN HARNESS
Disconnect PCM.
Measure resistance of HO2S SIG RTN circuit between the PCM harness connector pin and HO2S harness connector.
Is the resistance reading less than 5.0 ohms?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ). REPAIR open circuit.

H46 CHECK HO2S SIGNAL AND HO2S GND CIRCUITS FOR OPEN IN HARNESS
Disconnect PCM.
Measure resistance of HO2S SIG circuit between PCM harness connector pin and the HO2S harness connector.
Is the resistance reading less than 5.0 ohms?
Yes No
GO to H47 . REPAIR open circuit.

H47 CHECK HO2S CIRCUIT FOR SHORT TO GROUND IN HARNESS
Disconnect PCM.
Measure resistance between the HO2S SIG and PWR GND circuits; and the HO2S SIG and SIG RTN circuits at the PCM harness connector.
Is each resistance greater than 10,000 ohms?
Yes No
GO to H48 . REPAIR short circuit.

H48 CHECK HO2S CIRCUIT FOR SHORT TO GROUND
Disconnect PCM.
Reconnect HO2S.
Measure resistance between HO2S SIG and PWR GND circuits and HO2S SIG and SIG RTN circuits at the PCM harness connector.
Is each resistance greater than 10,000 ohms?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ). REPLACE HO2S.

H49 HO2S CIRCUIT CHECK (FOR RICH DTCS)
Disconnect the HO2S related to the DTC received.
Key on.
Access the correct HO2S PID(s).
Note: If viewing the HO2S11 (O2S11) PID on the 2.3L Focus, the engine must be running.

Is the reading 0.2 volt or less?
Yes No
KEY OFF. GO to H51 . KEY OFF. GO to H50 .

H50 CHECK HO2S CIRCUIT FOR SHORT TO VPWR AND HO2S HEATER GROUND IN HARNESS
Disconnect PCM.
Measure resistance between the HO2S SIG and VPWR circuits; and HO2S Signal and HO2S HTR circuits at the PCM harness connector.
Is each resistance greater than 10,000 ohms?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ). REPAIR short circuit.

H51 CHECK HO2S SIGNAL FOR SHORT TO HO2S HEATER CIRCUIT IN THE SENSOR
Suspect HO2S sensor disconnected.
Measure resistance between the HO2S SIG and HO2S HTR circuits at the HO2S connector.
Is the resistance greater than 10,000 ohms?
Yes No
KEY OFF. GO to H52 . KEY OFF. REPLACE HO2S.

H52 CHECK FUEL PRESSURE
WARNING: THE FUEL SYSTEM IS PRESSURIZED WHEN THE ENGINE IS NOT RUNNING. TO PREVENT INJURY OR FIRE, USE CAUTION WHEN WORKING ON THE FUEL SYSTEM. BECOME FAMILIAR WITH THE WARNING CAUTION AND NOTE IN PINPOINT TEST HC BEFORE SERVICING.

Connect battery charger.
Install fuel pressure gauge.
Key on, engine off.
Access Output Test Mode and run the fuel pump to obtain maximum fuel pressure.
NOTE: The fuel pump will only operate for approximately 8 seconds when Output Test Mode is selected and activated. (GO to Pinpoint Test HC to refer to the Fuel Delivery System Test Information Chart.)
Is the fuel pressure within range for the vehicle being diagnosed?
Yes No
KEY OFF.

GO to H53 . KEY OFF. GO to HC1 .

H53 CHECK FUEL SYSTEM FOR PRESSURE STABILITY — FAST LEAKDOWN
Cycle key on and off several times.
Key on and engine off, monitor fuel pressure gauge.
Does the fuel pressure remain within 34 kPa (5 psi) of the highest reading after 10 seconds?
Yes No
GO to H54 . Check fuel system for external leaks.

If external leak is detected, GO to HC1

If no external leak is detected, GO to H55

H54 CHECK FUEL SYSTEM FOR PRESSURE STABILITY WITH KEY ON — SLOW LEAKDOWN
Cycle key on and off several times.
Key on and engine off, monitor fuel pressure gauge.
Does the fuel pressure remain within 34 kPa (5 psi) of the highest reading after one minute?
Yes No
For HO2S DTCs displayed with misfire DTCs:

GO to H56 .

All other DTCs: GO to H59 GO to HC5 .

.

H55 CHECK INJECTOR FAULT PIDS AND ASSOCIATED DTCS
Access INJ1F-INJ10F PIDs.
Note: If misfire DTCs are present, access only injector fault PIDs corresponding to misfire DTCs.

Is DTC P0201 through P0210 or an injector(s) fault present?
Yes No
GO to H56 . For DTCs P0300 through P0310:

GO to HD12 .

For all other DTCs: GO to H59 .

cobra

o2 part 2

H56 CHECK FUEL INJECTOR(S) AND HARNESS RESISTANCE
Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

Note: This erases Continuous Memory DTCs.

Use the injector fault PID to determine the fuel injector circuit(s) requiring testing.

Disconnected PCM.
Measure resistance between suspect fuel injector and VPWR circuits at the PCM harness connector.
Is the resistance between 11.0-18.0 ohms?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ).

For Continuous Memory DTCs P0202 through P0210: Concern may be intermittent. Attempt to duplicate concern. If unable to duplicate concernGO to Z1 GO to H57 .

H57 CHECK FUEL INJECTOR HARNESS RESISTANCE
Disconnect fuel injector harness connector at the suspect fuel injector.
Measure resistance of VPWR circuit between PCM harness connector pin and the fuel injector harness connector.
Measure resistance of fuel injector circuit between PCM harness connector pin and the fuel injector harness connector.
Is each resistance less than 5.0 ohms?
Yes No
GO to H58 . REPAIR open harness circuit.

H58 CHECK FUEL INJECTOR HARNESS CIRCUIT FOR SHORT TO POWER AND GROUND
Disconnect PCM.
Suspect fuel injector disconnected.
Measure resistance between fuel injector SIG and VPWR circuits; and between fuel injector SIG and PWR GND circuits at the PCM harness connector.
Is each resistance greater than 10,000 ohms?
Yes No
GO to H59 . REPAIR short circuit.

H59 FLOW TEST FUEL INJECTOR(S)
Use the Rotunda Injector Tester or equivalent to flow test the fuel injectors according to the instructions for the fuel injector tester.
Is the leakage and flow within specification?
Yes No
DTC P0171 and P0174:

GO to H61 .

DTC P0172 and P0175:

Unable to duplicate or identify fault at this time. GO to Z1 .

For DTC P1131, P1151, P2195, and P2197:

GO to H60 .

For DTC P1132, P1152, P2196 and P2198:

GO to H64 . REPLACE fuel injector.

H60 CHECK FOR SECONDARY AIR INTRUSION
Note: If the vehicle is not equipped with Secondary Air Injection System,GO to H61 .

An HO2S always lean condition can be caused by:

Leak in hoses from secondary air injection pump to engine.
Secondary Air diverted upstream of HO2S.
Disconnect secondary air injection hose(s) from engine and plug engine side of secondary air injection system.
Key on, engine running and at operating temperature.
Activate Key On, Engine Running (KOER) Self-Test.
Is DTC P1131, P1151, P2195 or P2197 present?
Yes No
GO to H61 . Cause of DTC(s) is in the Secondary Air Injection System. GO to HM7 for Secondary Air Injection System diagnostics.

H61 INSPECT INDUCTION SYSTEM FOR AIR LEAKS
Inspect the following areas for signs of air leaks:
Inlet tube(s) from air cleaner to the throttle body.
Gaskets which seal the upper and lower intake manifold.
Vacuum hoses and lines for cracks and proper connections.
PCV system.
Are there any signs of leaks or damage?
Yes No
REPAIR as necessary. CONTINUOUS DTCs P0171 or P0174:

Unable to duplicate or identify fault at this time. GO to Z1 .

DTCs P1131, P1151, P2195, and P2197:

GO to H62 .

H62 CHECK CYLINDER COMPRESSION
Note: Use the Misfire DTC(s) displayed on prior DTC retrieval to determine which cylinder's compression to check.

Check cylinder compression. Refer to Engine, Section 303-00, 303-01 in the Workshop Manual.
Are cylinder compression readings within specification?
Yes No
For DTCs P1131, P1151, P2195 and P2197:

GO to H63 .

For DTCs P1132, P1152, P2196 and P2198:

GO to H64 .

Misfire DTCs displayed with fuel control DTCs:

GO to HD20 . REPAIR as necessary.

H63 CHECK HO2S'S ABILITY TO GENERATE A VOLTAGE GREATER THAN 0.5 VOLT
Any vacuum or air leaks can cause DTCs P1131, P1151, P2195 and P2197.

Possible causes:

Water contamination in connector.
Leaking vacuum actuators.
Engine sealing (Intake and IAC).
EGR system (valve).
PCV system (hose and valve).
Unmetered air leaks between throttle body and mass air flow (MAF) sensor assembly.
Inspect HO2S harness for chafing, burned wires or other damage and repair as necessary.
Unplug the suspect HO2S.
Connect digital multimeter to the HO2S Signal and HO2S SIG RTN or HO2S GND at the HO2S sensor connector.
Run engine at 2000 rpm for three minutes.
Rerun KOER Self-Test and monitor HO2S voltage on digital multimeter.
While monitoring, does the voltage ever increase to greater than 0.5 volts?
Yes No
KEY OFF. GO to H70 . KEY OFF. REPLACE HO2S.

H64 ATTEMPT TO GENERATE DTC P1131, P1151, P2195 OR P2197
HO2S disconnected.
Jumper HO2S Signal at the HO2S harness vehicle connector to the battery negative post.
Activate Key On Engine Running (KOER) Self-Test.
Is DTC P1131, P1151, P2195 or P2197present?
Yes No
KEY OFF. REMOVE jumper. GO to H65 . KEY OFF. REMOVE jumper. RECONNECT HO2S. DISCONNECT PCM. INSPECT both ends of connector for damaged or pushed out pins, moisture, corrosion, loose pins and REPAIR as necessary. If OK, REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ).

H65 HO2S SENSOR VOLTAGE CHECK
HO2S disconnected.
Connect digital multimeter to HO2S SIG circuit and HO2S SIG RTN at the HO2S sensor connector.
Disconnect vacuum hose from vacuum tree.
Start engine and run at 2000 rpm.
Does the voltage reading indicate less than 0.4 volt within 30 seconds?
Yes No
KEY OFF. RECONNECT vacuum hose and HO2S. GO to H70 . KEY OFF. REPLACE HO2S. PERFORM KOER SELF-TEST. If DTCs P1132 or P1152 still exist, REPLACE PCM (refer to Section 2, Flash EEPROM).

H70 MONITOR HO2S (PID) FOR SWITCHING WHILE PERFORMING WIGGLE TEST
Key on, engine running.
Engine at operating temperature.
Note: HO2S displayed as O2S on Scan Tool.

Access suspect HO2S PID.
Wiggle, bend and shake small sections of the Electronic Engine Control harness from the PCM to the HO2S.
Note: Do not compare HO2S switch rate from Bank to Bank as an indication of the sensor's function. It is normal to have a variance in switch ratio from Bank to Bank.

While monitoring the HO2S PID, did the HO2S stop switching?
Yes No
KEY OFF. ISOLATE area of harness concern causing lack of HO2S switches and repair. KEY OFF. GO to H71 .

H71 TEST DRIVE WHILE MONITORING HO2S PID FOR SWITCHING
Note: This test step requires an observer to monitor HO2S PID.

Access HO2S PID.
Access LOOP PID, ensure that vehicle is in Closed Loop before proceeding.
While observer views PIDs, test drive vehicle in a manner consistent with the Freeze Frame Data in an attempt to simulate the original fault.
Does the HO2S switch?
Yes No
KEY OFF. UNABLE to duplicate fault. Testing complete at this time. KEY OFF. REPLACE HO2S.

H80 DTC P0136 AND P0156 MONITOR DOWNSTREAM HO2S OUTPUT VOLTAGE FOR ACTIVITY. DTCs P1137, P1138, P1157, P1158, P2270, P2271, P2272 AND P2273 INDICATE LACK OF HO2S SWITCHING
Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

Note: It is necessary to address all Continuous Memory Ignition and Misfire DTCs, if received during Continuous Memory testing, before addressing any KOER HO2S DTCs.

DTC P0136, P1137, P1138, P2270 and P2271=HO2S-12
DTC P0156, P1157, P1158, P2272 and P2273=HO2S-22
Visually inspect for:
pinched, shorted and corroded wiring and pins
water / oil / fluid contamination in HO2S and PCM connectors
crossed sensor wires
contaminated or damaged sensor
Were any concerns found during inspection?
Yes No
REPAIR as necessary. Continuous Memory DTC P0136 and P0156:

GO to H81 .

All others:

GO to H82 .

H81 CHECK FOR KOER DTCS P1137, P1157, P1138, P1158, P2270, P2271, P2272 AND P2273
Key on.
Engine at 2000 rpm for 3 minutes.
Activate KOER Self-Test.
Check for DTCs.
Is DTC P1137, P1138, P1157, P1158, P2270, P2271, P2272 or P2273 present?
Yes No
KEY OFF. GO to H82 . KEY OFF. For DTC P0136 and P0156:

Unable to duplicate or identify at this time. GO to Z1 .

H82 CHECK EXHAUST SYSTEM FOR LEAKS
Note: Any exhaust leaks between the engine and the end of the catalyst can cause DTC P0136 and P0156.

Place vehicle on a hoist, transmission in PARK, emergency brake applied, raise vehicle.
Inspect the following:
Exhaust flanges for leaks.
HO2S torque.
incorrect exhaust installation
aftermarket exhaust
Check for punctures and cracks in catalyst and pipes leading to them.
Is an exhaust leak present?
Yes No
REPAIR as necessary. GO to H83 .

H83 CHECK HO2S HARNESS CIRCUIT FOR SHORT TO VPWR AND GROUND
Disconnect PCM.
Disconnect suspect HO2S.
Measure resistance between HO2S SIG and SIG RTN circuits at the PCM harness connector.
Measure resistance between HO2S SIG circuit and VPWR and VREF circuits at the PCM harness connector.
Measure resistance between HO2S SIG circuit and PWR GND circuit at the PCM harness connector.
Is the resistance greater than 10,000 ohms?
Yes No
GO to H84 . REPAIR short in harness.

H84 CHECK HO2S SIGNAL CIRCUIT AND HO2S SIGNAL RETURN CIRCUITS FOR OPEN IN HARNESS
Measure resistance of VPWR circuit between the PCM harness connector pin and the HO2S harness connector.
Measure resistance of HO2S SIG circuit between the PCM harness connector pin and the HO2S harness connector.
Measure resistance of SIG RTN circuit between the PCM harness connector pin and HO2S SIG RTN vehicle harness connector.
Is the resistance reading less than 5.0 ohms?
Yes No
GO to H85 . REPAIR open circuit.

H85 CHECK HO2S CIRCUIT VOLTAGE
Connect PCM.
Suspect HO2S connected to harness.
Key on, engine off.
Note: HO2S displayed as O2S on Scan Tool.

Access the correct HO2S PID.
Is the voltage greater than 1.5 volts?
Yes No
KEY OFF. GO to H88 . KEY OFF. GO to H86 .

H86 CHECK HO2S GROUND CIRCUIT IN THE PCM
Disconnect PCM.
Measure resistance between SIG RTN and PWR GND circuits at the PCM connector.
Is the resistance reading less than 5.0 ohms?
Yes No
GO to H87 . REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ).

H87 HO2S CIRCUIT CHECK
PCM connected.
Suspect HO2S disconnected.
Jumper VPWR to HO2S SIG circuit at the HO2S harness connector.
Key on.
Access HO2S PID.
Is the PID value greater than 1.5 volts?
Yes No
REPLACE HO2S. REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ).

H88 CHECK FOR OVER VOLTAGE ON THE HO2S CIRCUIT IN THE PCM
Key on.
HO2S disconnected.
Measure voltage between SIG RTN circuit at the HO2S harness connector and battery negative post.
Measure voltage between HO2S SIG circuit at the HO2S harness connector and battery negative post.
Are either voltage readings greater than 1.5 volts?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ). REPLACE HO2S.

H100 KOER DTC P1127
Address all other DTCs before proceeding with this pinpoint test.
Key on, engine running.
Access all HO2S heaters and HO2S heater monitor PIDs.
Do all PIDs switch or indicate ON?
Yes No
Engine still operating. PERFORM KOER Self-Test. Operate the engine until all PIDs indicate on. PERFORM KOER Self-Test.

H110 DTCS P0040, P0041, P1128 AND P1129 KOER
Note: Refer to the PCM harness connector pin numbers in the beginning of this pinpoint test.

P0040 and P1128 refer to the upstream HO2S.
P0041 and P1129 refer to the downstream HO2S.
Visually inspect vehicle HO2S harness connector(s) for any indication of being crossed (stretched wires, wire harnesses not mounted properly).
Are there crossed connections or wires?
Yes No
REPAIR as necessary. GO to H111 .

H111 VERIFY PROPER HO2S SIGNAL PIN LOCATION
PCM disconnected.
Disconnect both of the suspect HO2S sensors from the vehicle harness connector.
P0040 and P1128 = HO2S 11/21 Upstream
P0041 and P1129 = HO2S 12/22 Downstream
Measure resistance of HO2S signal circuits between PCM harness connector pins and HO2S harness connector.
Is the resistance less than 5.0 ohms?
Yes No
Unable to duplicate or identify at this time. GO to Z1 . CONNECT HO2S connector to proper HO2S signal pins in the PCM harness connector or HO2S harness connectors. RERUN Quick Test.

H115 CHECK HO2S CIRCUIT VOLTAGE
Visually inspect the HO2S circuit for exposed wiring, water contamination, corrosion and proper assembly.
On some applications, a hoist is required to access the HO2S harness.
Key on, engine running
Note: HO2S is displayed as O2S on Scan Tool.

Access suspect HO2S PID(s).
P0132 = HO2S-11
P0138 = HO2S-12
P0152 = HO2S-21
P0158 = HO2S-22
Is PID voltage 1.5 volts or greater?
Yes No
GO to H116 . Concern may be intermittent. Attempt to duplicate concern, perform wiggle test on suspect circuit harness and component.

If concern was reproduced: Perform this Pinpoint test again.

All others:GO to Z1

H116 CHECK HO2S SIGNAL FOR SHORT TO POWER INSIDE OF SENSOR
Key off.
Suspect HO2S disconnected.
Key on, engine off.
Access suspect HO2S PID(s).
Note: If viewing the HO2S11 (O2S11) PID on the 2.3L Focus, the engine must be running.

Is PID voltage .5 volts or greater?
Yes No
GO to H117 Replace HO2S sensor.

H117 CHECK HO2S SIGNAL FOR SHORT TO POWER IN HARNESS
Key off.
Suspect HO2S disconnected.
PCM disconnected.
Check resistance between HO2S Signal circuit and both VPWR and VREF circuits at the PCM connector.
Are resistance values greater than 10,000 Ohms?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ). Repair short to power in harness between PCM and HO2S.




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Another "captain obvious" item I thought of yesterday, but forgot to include in my first post, was the heat range of sparkplug currently installed. Saw that you weren't sure what type of plugs were in there - if the previous owner was running nitrous, I bet they were one (or possibly even two) heat range colder than the factory plug rating.

ie - factory heat range for '01 cobra calls for Motorcraft 32 (your choice platinum or copper), down to a 22 plug (1 step colder) or even a 12 (two steps colder) plug in certain applications.

I could see the engine running rough and/or possibly fouling the plugs with a sparkplug that is two steps colder than what a regular NA application calls for. Hopefully the shop already checked/replaced the sparkplugs...at least they were able to get the correct fuel injectors in for you (should be 24 lb injectors for '01 cobra).


At least the used car dealership is paying for the repairs/troubleshooting so far.

If the Ford dealership can't resolve the issue, it might not be a bad idea to walk away from this specific car and/or consider another vehicle on the used car dealer's lot (or try to get out of the vehicle purchase altogether, including a refund of your first monthly payment, since the vehicle has issues).

Auction cars can often come with headaches, and that snake sure seems to have a migraine.


G'luck...

You sure you really want this car?

lhillebrand said:

Just spoke with the mechanic, he said the check engine light had been unplugged. Also they said it is dumping a lot of gas. The gas is dripping out of the right exhaust pipe.

Click to expand...

Geez, so the previous owner unplugged the bulb for the check engine light on the dash/speedo cluster - not cool.


At least they are starting to make progress. Once they have the diagnostic trouble codes from the car's computer, they should be able to narrow down the potential items that are tripping the check engine light.

Odds are that everything will not be fine and that you should find another cobra.