OK need some info or I am going to set it on fire

what was the new code??

on the rear o2s the blue plug is the left and purple is right.

po 420 bank 1/p0430 bank2

P0420 - Catalyst System Efficiency Below Threshold (Bank 1) Indicates Bank 1 catalyst system efficiency is below the acceptable threshold Use of leaded fuel
Damaged HO2S
Malfunctioning ECT
High fuel pressure
Damaged exhaust manifold
Damaged catalytic converter
Oil contamination
Cylinder misfiring
Downstream HO2S wires improperly connected
Damaged exhaust system pipe
Damaged muffler/tailpipe assembly
Retarded spark timing
Compare HO2S upstream and downstream switch rate and amplitude. Under normal closed loop fuel conditions, high efficiency catalysts have oxygen storage which makes the switching frequency of the downstream HO2S very slow and reduces the amplitude of those switches as compared to the upstream HO2S. As catalyst efficiency deteriorates, its ability to store oxygen declines and the downstream HO2S signal begins to switch more rapidly with increase amplitude, approaching the switching rate and amplitude of the upstream HO2S. Once beyond an acceptable limit the DTC is set. 2003 PCED OBD SECTION 5: Pinpoint Tests
Procedure revision date: 06/11/2003

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HF: Catalyst Efficiency Monitor and Exhaust Systems HF: Introduction

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HF1 DTCs P0420 OR P0430: CHECK FOR MISFIRE DETECTION MONITOR DTCS
NOTE 1: Be sure customer has not:

Refueled vehicle with leaded gasoline.
Noticed high vehicle oil consumption. (Engines that consume oil at a high rate will deposit high levels of phosphorus on the catalyst and reduce the catalyst efficiency)
NOTE 2: If entering this Pinpoint Test for symptoms only, immediately GO to HF5 .

NOTE 3: Internal deterioration of a catalytic converter is usually caused by abnormal engine operation upstream of the catalyst. Events that can produce higher than normal temperatures in the catalyst are particularly suspect. For example, misfiring can cause higher than normal catalyst operating temperatures.

Retrieve and record all Continuous Memory DTCs (MIL and non-MIL).
Were any of the following Misfire Detection Monitor DTCs recorded: P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0309, P0310, P0315, P0316 and P1309?
Yes No
GO to Section 4, Powertrain Diagnostic Trouble Code (DTC) Charts , to address the Misfire Detection Monitor DTCs. GO to HF2 .

HF2 CHECK FOR HO2S DTCS
NOTE: Incorrect HO2S signal input (such as rich/lean input signal when the engine is operating under lean/rich conditions) can cause an abnormal temperature increase in the catalyst. Refer to Section 1 , Heated Oxygen Sensor (HO2S) Monitor for possible HO2S DTCs.

Were there any HO2S DTCs (not including the initial P0420 or P0430 DTCs)?
Yes No
GO to, Section 4, Powertrain Diagnostic Trouble Code (DTC) Charts , to address the HO2S DTCs. GO to HF3 .

HF3 CHECK FOR ECT OR CHT SENSOR DTCS
NOTE: ECT or CHT sensor DTCs can indicate that the thermostat is not operating correctly or that the engine coolant level is not filled to specification, producing above normal operating temperatures.

Were any of the following ECT or CHT sensor DTCs recorded in HF1: P0117, P0118, P0125, P0128, P1117, P1285, P1288, P1289, P1290 and P1299?
Yes No
GO to Section 4, Powertrain Diagnostic Trouble Code (DTC) Charts , to address the ECT or CHT sensor DTCs. GO to HF4 .

HF4 CHECK FOR ANY OTHER DTCS
Were any other DTCs recorded in HF1 (not including the initial P0420 or P0430 DTCs)?
Yes No
GO to Section 4, Powertrain Diagnostic Trouble Code (DTC) Charts , to address the DTCs. GO to HF5 .

HF5 CHECK REAR HO2S WIRING AND PCM CONNECTIONS
NOTE: If the electrical connections of the rear HO2S are interchanged/crossed, the Catalyst Efficiency Monitor Test will fail.

Inspect the wiring of each rear HO2S for proper routing and connection.
Disconnect the PCM, inspect for damaged or pushed out pins, corrosion and loose wires.
Are there any concerns with the HO2S wiring or the PCM connection?
Yes No
REPAIR any wiring or connection concerns. For PCM pin concerns, REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ). COMPLETE Catalyst Monitor OBD Drive Cycle to verify repair (Refer to Section 2, Drive Cycles ). No Electronic EC root causes related to the DTCs or symptoms. GO to HF6 .

HF6 CHECK FUEL PRESSURE
WARNING: THE FUEL SYSTEM WILL REMAIN PRESSURIZED WHEN THE ENGINE IS NOT RUNNING. TO PREVENT INJURY OR FIRE, USE CAUTION WHEN WORKING ON THE FUEL SYSTEM.

NOTE: Fuel pressures above specification can produce an abnormally rich air/fuel mixture. The rich air/fuel mixture can cause higher than normal catalyst operating temperatures.

RETURN FUEL SYSTEM
Inspect the vacuum hose going to the fuel pressure regulator for proper installation and cracks. Repair as necessary.
Verify vacuum source to fuel pressure regulator.
MECHANICAL RETURNLESS FUEL SYSTEM
If applicable, inspect the vacuum hose going to the fuel rail pulse damper for proper installation and cracks. Repair as necessary.
Install fuel pressure gauge. NOTE: On Electronic Returnless Fuel System, the fuel pressure can be monitored by scan tool using the Fuel Rail Pressure (FRP) sensor PID.
Start and run the engine at idle. Record the fuel pressure.
Increase engine speed to 2500 rpm and maintain for one minute. Record the fuel pressure. GO to Pinpoint Test HC and compare fuel pressure to the Fuel Pressure Specification Chart at the beginning of the pinpoint.
Key off.
Was the fuel pressure within specifications?
Yes No
Fuel pressure is OK. If applicable, REMOVE the fuel pressure gauge. GO to HF7 . Fuel pressure is out of specification.

GO to HC4 , Fuel Delivery Systems in Section 5 for diagnosis.

HF7 CHECK FOR OBVIOUS LEAK SOURCES IN THE EXHAUST SYSTEM
NOTE: If a catalyst is in series with a leaking exhaust system, it can fail the Catalyst Efficiency Monitor test.

Inspect the following for leaks, cracks, loose connections or punctures:
Exhaust manifold.
Front exhaust pipe.
Rear exhaust pipe.
Muffler/tailpipe assembly.
Are the above components free of cracks and punctures, etc.?
Yes No
GO to HF8 . REPAIR the leak source(s). COMPLETE Catalyst Monitor OBD Drive Cycle to verify repair (Refer to Section 2, Drive Cycles ).

HF8 CHECK FOR OBVIOUS RESTRICTIONS IN THE EXHAUST SYSTEM
A slight pressure in the exhaust system is normal, but excessive exhaust back pressure seriously affects engine operation. Causes of high exhaust back pressure are dents or obstructions in the exhaust pipe, a plugged catalytic converter or muffler.

Inspect the following for dents, areas of collapsed material and unusual bending:
Front and rear exhaust pipes.
Catalytic converter.
Muffler/tailpipe assembly.
Are the components free of dents and areas of collapsed or unusual bending or damaged?
Yes No
GO to HF9 . REPAIR the restricted component(s) as necessary. COMPLETE Catalyst Monitor OBD Drive Cycle to verify repair (Refer to Section 2, Drive Cycles ).

HF9 CHECK FOR EXCESSIVE EXHAUST BACK PRESSURE
If available install a exhaust back pressure tester and follow tool manufacturer installation and testing instructions.
NOTE: If no tester is available. GO to HF10 .
Typical exhaust back pressure (when measured near the exhaust manifold and at normal engine operating temperature) should not exceed 20.7 kPa (3 PSI) at idle and 55.2 kPa (8 PSI) at WOT under load.
Did exhaust back pressure test indicate a restriction?
Yes No
REPAIR the restricted component(s) as necessary. COMPLETE Catalyst Monitor OBD Drive Cycle to verify repair (Refer to Section 2, Drive Cycles ). For further diagnosis of symptom (e.g. Lack of Power, Loss of Power, or No Start) REFER to Section 3 , Symptom Charts No indications of restrictions or leaks have been detected in the exhaust system. If here because of DTCs P0420 or P0430, the catalytic converter is chemically inactive. REPLACE the catalyst that is located between the monitored H02S Sensors, only for the bank referenced, (P0420 Bank 1), (P0430 Bank 2). Do not replace any unmonitored catalyst unless it is serviced as an assembly. COMPLETE Catalyst Monitor OBD Drive Cycle to verify repair (Refer to Section 2, Drive Cycles ). For further diagnosis of symptom (e.g. Lack of Power, Loss of Power, or No Start) REFER to Section 3 , Symptom Charts.

HF10 CHECK MANIFOLD VACUUM FOR INDICATION OF EXCESSIVE EXHAUST SYSTEM RESTRICTION
Attach a vacuum gauge to the intake manifold vacuum source.
Monitor RPM with scan tool or tachometer.
Observe the vacuum gauge needle while completing the following:
NOTE: The vacuum gauge reading may be normal when the engine is first started and idling. However, excessive restriction in the exhaust system will cause intake manifold vacuum to decrease with the engine at a steady/constant idle speed.
Start the engine and gradually increase the engine speed to 2000 rpm with the transmission in NEUTRAL.
Decrease engine speed to base idle rpm.
Key off.
Did manifold vacuum rise above 54 kPa (16 inches-Hg) with the engine speed at 2000 rpm?
Yes No
GO to HF11 . Manifold vacuum did not reach an acceptable level. GO to HF12 to check for excessive restriction in the exhaust system.

HF11 CHECK MANIFOLD VACUUM FOR INDICATION OF MODERATE EXHAUST SYSTEM RESTRICTION
Key on, engine idling.
Increase the engine speed gradually from base idle rpm to 2000 rpm with the transmission in NEUTRAL.
Observe the speed the vacuum gauge needle rises, while maintaining the increased engine rpm.
NOTE 1: On a non-restricted exhaust system, the vacuum gauge needle will rise quickly to the normal range as the increased rpm is maintained.
NOTE 2: On a restricted exhaust system, the vacuum gauge needle will rise slowly to the normal range as the increased rpm is maintained.
NOTE 3: The rate of speed the vacuum gauge needle rises to the normal range is slower on a restricted system than on a non-restricted system as the increased rpm is maintained.
Decrease engine speed to base idle rpm.
Key off.
Is the rate of speed that the vacuum gauge needle rises back to the normal range (above 54 kPa (16 inches-Hg)) much slower than that of a non-restricted system?
Yes No
A moderate restriction may be present. GO to HF12 . No indications of restrictions or leaks have been detected in the exhaust system. If here because of DTCs P0420 or P0430, the catalytic converter is chemically inactive. REPLACE the catalyst that is located between the monitored H02S Sensors, only for the bank referenced, (P0420 Bank 1), (P0430 Bank 2). Do not replace any unmonitored catalyst unless it is serviced as an assembly. COMPLETE Catalyst Monitor OBD Drive Cycle to verify repair (Refer to Section 2, Drive Cycles ). For further diagnosis of symptom (e.g. Lack of Power, Loss of Power, or No Start) REFER to Section 3 , Symptom Charts.

HF12 CHECK MANIFOLD VACUUM WITH EXHAUST MANIFOLD DISCONNECTED FOR INDICATION OF A RESTRICTION
NOTE: An intake manifold gasket leak can also cause the vacuum gauge needle to remain well below the normal range.

Disconnect exhaust system immediately after the exhaust manifold.
GO to HF10 and repeat the vacuum measurement.
Did the vacuum needle QUICKLY rise above 54 kPa (16 inches-Hg) with the engine speed at 2000 rpm?
Yes No
The exhaust system restriction is downstream of the exhaust manifold. RECONNECT exhaust system at exhaust manifold. GO to HF13 . A restriction is present in the exhaust manifold. INSPECT each exhaust port for casting flash/restrictions by dropping a length of chain into it (NOTE: Do not use a wire or lamp to check the ports. The restriction can be small enough for both to pass through, but large enough to cause excessive back-pressure at high engine rpm.) REPLACE the exhaust manifold if unable to remove the casting flash/restriction. COMPLETE Catalyst Monitor OBD Drive Cycle to verify repair (Refer to Section 2, Drive Cycles ).

HF13 CHECK MANIFOLD VACUUM WITH MUFFLER/TAILPIPE ASSEMBLY DISCONNECTED FOR INDICATION OF A RESTRICTION
Disconnect muffler/tailpipe assembly from the catalytic converter.
GO to HF10 to repeat the vacuum measurement.
Did the vacuum needle QUICKLY rise above 54 kPa (16 inches-Hg) with the engine speed at 2000 rpm?
Yes No
There is a restriction in the muffler/tailpipe assembly. REPLACE the muffler/tailpipe assembly. COMPLETE Catalyst Monitor OBD Drive Cycle to verify repair (Refer to Section 2, Drive Cycles ). There is a restriction in the catalytic converter. REPLACE the catalytic converter. NOTE: On vehicle applications where their is more than one catalyst, REPLACE only the damaged catalyst assembly. INSPECT the muffler to be certain converter debris has not entered. COMPLETE Catalyst Monitor OBD Drive Cycle to verify repair (Refer to Section 2, Drive Cycles ).




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just a little advice, mils dont always work 100% of the time. might be a good time to get you a handheld from your preferd dealer/tuner and have the rear 02s cut off.

02 code 420?????

read all of the tests closer...420 is upstream to downstream switch rate?here is cat monitoring 2003 PCED OBD SECTION 1: Description and Operation
Procedure revision date: 08/28/2003

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Catalyst Efficiency Monitor
The Catalyst Efficiency Monitor uses an oxygen sensor before and after the catalyst to infer the hydrocarbon (HC) efficiency based on oxygen storage capacity of the catalyst. Under normal, close-loop fuel conditions, high efficiency catalysts have significant oxygen storage. This makes the switching frequency of the rear heated oxygen sensor (HO2S) very slow and reduces the amplitude of those switches as compared to the switching frequency and amplitude of the front HO2S. As the catalyst efficiency deteriorates due to thermal and/or chemical deterioration, its ability to store oxygen declines. The post-catalyst or downstream HO2S signal begins to switch more rapidly with increasing amplitude, approaching the switching frequency and amplitude of the pre-catalyst or upstream HO2S.

Note: The predominant failure mode for high mileage catalysts is chemical deterioration (phosphorus deposition on the front brick of the catalyst), not thermal deterioration.

All vehicles utilize an FTP-based (Federal Test Procedure) catalyst monitor. This simply means that the catalyst monitor must run during a standard FTP emission test. This differs from the 20-second steady state catalyst monitor used in 1994 through some 1996 vehicles. Currently, two slightly different versions of the catalyst monitor are utilized - the Switch Ratio method and the Index Ratio method. Beginning with the 2001 model year and beyond, both versions will continue to be used in subsequent model years.

Switch Ratio Method
In order to assess catalyst oxygen storage, the monitor counts front and rear HO2S switches during part-throttle, close-loop fuel condition after the engine is warmed-up and inferred catalyst temperature is within limits. Front switches are accumulated in up to nine different air mass regions or cells although three air mass regions is typical. Rear switches are counted in a single cell for all air mass regions. When the required number of front switches has accumulated in each cell, the total number of rear switches is divided by the total number of front switches to compute a switch ratio. A switch ratio near 0.0 indicates high oxygen storage capacity; hence high HC efficiency. A switch ratio near 1.0 indicates low oxygen storage capacity; hence low HC efficiency. If the actual switch ratio exceeds a calibrated threshold switch ratio, the catalyst is considered failed.

Inputs from ECT or CHT (warm engine), IAT (not extreme ambient temperatures), MAF (greater than minimum engine load), VSS (within vehicle speed window) and TP (at part-throttle) are required to enable the Catalyst Efficiency Monitor.
Typical Switch Ratio Monitor Entry Conditions:

Part throttle with no rapid throttle transients
Minimum 330 seconds since start-up at 70° F (21°C)
Engine coolant temperature is between 170° F (76.6°C) and 230°F (110°C)
Intake air temperature is between 20°F (-6°C) and 180°F (82°C)
Engine load greater than 10%
Time since entering close loop is 30 seconds
Vehicle speed is between 5 and 70 mph (8 and 112 km/h)
Inferred Catalyst Mid-bed Temperature of 900° F (482° C)
Mass air flow is between 1 and 5 lbs/min
Fuel level greater than 15%
EGR is between 1 and 12%
The DTCs associated with this test are DTC P0420 (Bank 1 or Y-pipe system) and P0430 (Bank 2). Because an Exponentially Weighted Moving Average algorithm is used for malfunction determination, up to six driving cycles may be required to illuminate the MIL during normal customer driving. If KAM is reset or the battery is disconnected, a malfunction will illuminate the MIL in 2 drive cycles.
Index Ratio Method
In order to assess catalyst oxygen storage, the catalyst monitor counts front HO2S switches during part-throttle, closed-loop fuel conditions after the engine is warmed-up and inferred catalyst temperature is within limits. Front switches are accumulated in up to three different air mass regions or cells. While catalyst monitoring entry conditions are being met, the front and rear HO2S signal lengths are continually being calculated. When the required number of front switches has accumulated in each cell, the total signal length of the rear HO2S is divided by the total signal length of the front HO2S to compute a catalyst index ratio. An index ratio near 0.0 indicates high oxygen storage capacity; hence high HC efficiency. A switch ratio near 1.0 indicates low oxygen storage capacity; hence low HC efficiency. If the actual index ratio exceeds the threshold index ratio, the catalyst is considered failed.

Inputs from ECT or CHT (warm engine), IAT (not extreme ambient temperatures), MAF (greater than minimum engine load), VSS (within vehicle speed window) and TP (at part-throttle) are required to enable the Catalyst Efficiency Monitor.
Typical Index Ratio Monitor Entry Conditions:

Minimum 330 seconds since start-up at 70° F (21°C)
Engine coolant temperature is between 170° F (76.6°C) and 230°F (110°C)
Intake air temperature is between 20°F (-6°C) and 180°F (82°C)
Time since entering close loop is 30 seconds
Inferred Rear HO2S sensor temperature of 900° F (482° C)
EGR is between 1 and 12%
Part throttle, maximum rate of change 0.2 volts/0.050 sec
Vehicle speed is between 5 and 70 mph (8 and 112 km/h)
Fuel level greater than 15%
First Air Flow Cell
Engine RPM 1,000 to 1,300 rpm.
Engine load 15 to 35%.
Inferred catalyst temp. 850° F (454° C) to 1,200° F (649° C).
Number of front O2 switches: 50.
Second Air Flow Cell
Engine RPM 1,200 to 1,500 rpm.
Engine load 20 to 35%.
Inferred catalyst temp. 900° F (482° C) to 1,250° F (677° C).
Number of front O2 switches: 70.
Third Air Flow Cell
Engine RPM 1,300 to 1,600 rpm.
Engine load 20 to 40%.
Inferred catalyst temp. 950° F (510° C) to 1,300° F (704° C).
Number of front O2 switches: 30.
The DTCs associated with this test are DTC P0420 (Bank 1or Y-pipe system) and P0430 (Bank 2). Because an Exponentially Weighted Moving Average algorithm is used for malfunction determination, up to six driving cycles may be required to illuminate the MIL during normal customer driving. If KAM is reset or the battery is disconnected, a malfunction will illuminate the MIL in 2 drive cycles.
General Catalyst Monitor Operation
Monitor execution is once per drive cycle. Typical monitor duration is 700 seconds. In order for the catalyst monitor to run, the HO2S monitor must be complete and Secondary AIR and EVAP system functional with no stored DTCs. If the catalyst monitor does not complete during a particular driving cycle, the already accumulated switch/signal data is retained in Keep Alive Memory and is used during the next driving cycle to allow the catalyst monitor a better opportunity to complete.

Rear HOS2 sensors can be located in various configurations to monitor different kinds of exhaust systems. In-line engines and many V-engines are monitored by their individual bank. A rear HO2S sensor is used along with the front, fuel control HO2S sensor for each bank. Two sensors are used on an in-line engine; four sensors are used on a V-engine. Some V-engines have exhaust banks that combine into a single underbody catalyst. These systems are referred to as Y-pipe systems. They use only one rear HO2S sensor along with the two front, fuel-control HO2S sensors. Y-pipe system uses three sensors in all. For Y-piped systems, the two front HO2S sensor signals are combined by the PCM software to infer what the HO2S signal would have been in front of the monitored catalyst. The inferred front HO2S signal and the actual single, rear HO2S signal is then used to calculate the switch ratio.

Most vehicles that are part of the Low Emission Vehicle (LEV) catalyst monitor phase-in will monitor less than 100% of the catalyst volume. Often this is the first catalyst brick of the catalyst system. Partial volume monitoring is done on LEV and Ultra Low Emission Vehicle (ULEV) vehicles in order to meet the 1.75 emission standard.

Many applications that utilize partial-volume monitoring place the rear HO2S sensor after the first light-off catalyst can or, after the second catalyst can in a three-can per bank system. (A few application placed the HO2S in the middle of the catalyst can, between the first and second bricks).

Some 2003 model year Partial Zero Emission Vehicles (PZEV) will utilize three sets of HO2S sensors. The front sensors or stream 1 (HO2S11/HO2S21) are the primary fuel control sensors. The next sensors downstream or stream 2 in the exhaust are utilized to monitor the light-off catalyst (HO2S12/HO2S22). The last sensors downstream or stream 3 in the exhaust (HO2S13/HO2S23) are utilized for very long term fuel trim in order to optimize catalyst efficiency (For Aft Oxygen Sensor Control). For addition heated oxygen sensor information, refer to the Heated Oxygen Sensor (HO2S) Monitor later in this section.

Index ratios for ethanol (Flex fuel) vehicle vary based on the changing concentration of alcohol in the fuel. The malfunction threshold typically increases as the percent of alcohol increases. For example, a malfunction threshold of 0.5 may be used at E10 (10% ethanol) and 0.9 may be used at E85 (85% ethanol). The malfunction thresholds are therefore adjusted based on the percentage of alcohol in the fuel.





Figure 5: Catalyst Efficiency Monitor



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hotcobra03 said:

read all of the tests closer...420 is upstream to downstream switch rate?

Click to expand...

Well, switch ratio, not rate.

"In order to assess catalyst oxygen storage, the monitor counts front and rear HO2S switches during part-throttle, close-loop fuel condition after the engine is warmed-up and inferred catalyst temperature is within limits. Front switches are accumulated in up to nine different air mass regions or cells although three air mass regions is typical. Rear switches are counted in a single cell for all air mass regions. When the required number of front switches has accumulated in each cell, the total number of rear switches is divided by the total number of front switches to compute a switch ratio. A switch ratio near 0.0 indicates high oxygen storage capacity; hence high HC efficiency. A switch ratio near 1.0 indicates low oxygen storage capacity; hence low HC efficiency. If the actual switch ratio exceeds a calibrated threshold switch ratio, the catalyst is considered failed. "

This makes sense. If the number of front (oxygen sensor lean/rich or rich/lean) switches is Sf and the number of rear (oxygen sensor lean/rich or rich/lean) switches is Sr, then when Sr/Sf is close to unity it means Sr and Sf are close to being the same. This means that the chemistry of the exhaust seen by the rear sensor is basically the same as the chemistry of the exhaust seen by the front sensor and this means the catalyst isn't doing anything.

If Sr/Sf is close to zero, it means that the rear sensor didn't switch much compared to the front sensor and thus the catalyst is altering the exhaust chemistry as expected.

If the rear O2 signal is filtered aggressively then the number of switches is artificially reduced electrically. This is what a MIL-elim does.

my bad

rate/ratio...anyway its all abunch of numbers..understanding what he is reading with his tuner, he will find the problem...us telling him what to change is good ,i also like to know why,,,,with his tuner he should be able to read 02s to see whats going on,,,,,,,,,,,,,,,,,yes,,,,,,,,,,,with the preadator i have all parts of 02s are readable in someway or another

o2s rear plugs

driverside #22,blue (C141)passengerside #12purple/violet(C142).

PLUGS

c141/c142

any update?

seeing how things are going?