Check Engine

ford said:

HW7 DTC P1443: CHECK THE VOLTAGE ON THE PURGE FLOW (PF) SENSOR CIRCUIT VOLTAGE WITH ENGINE RUNNING
Continuous Memory Diagnostic Trouble Code (DTC) P1443 indicates an incorrect evaporative system purge control valve flow.

Possible causes:

Obstructed, open or cracked hoses between EVAP canister purge valve and intake manifold.
Damaged EVAP canister purge valve.
Damaged PF sensor.
Key off.
Disconnect PF sensor.
Check for loose pins or broken wires by pulling moderately on the PF, VPWR and PWR GND circuits at PF sensor harness connector.
Repair as necessary.
Reconnect PF sensor.
Connect scan tool.
Key on, engine running.
Access EVAPPF PID.
Key off.
Did the EVAPPF PID fluctuate around 2.50 volts or 1.00 volt in one minute?
Yes No
For voltage from 2.20 to 2.60 volts:

GO to HW18 .

For voltage from 0.90 to 1.10 volts:

GO to HW19 . GO to HW8 .

HW8 DTC P1443: VISUAL CHECK OF EVAPORATIVE EMISSION SYSTEM

Continuous Memory Diagnostic Trouble Code (DTC) P1443 indicates an Evaporative emission control system or evaporative canister purge valve (mechanical) malfunction.

Possible causes:

Damaged EVAP canister.
Pinched, plugged, blocked, cracked, cut or disconnected fuel vapor tubes/hoses between the fuel tank, EVAP canister, EVAP canister purge valve, purge flow (PF) sensor, and the engine intake manifold.
Damaged EVAP canister purge valve.
Damaged PF sensor.
EVAP CANISTER PURGE, or PF circuit shorted to VPWR.
Note: Fuel saturation of EVAP canister cannot be effectively checked by the canister weight or intensity of odor (smell).

Check for kinked or pinched fuel vapor tubes/hoses between EVAP canister, EVAP canister purge valve and engine intake manifold.
Check for cracked or smashed EVAP canister.
Is a fault indicated?
Yes No
REPAIR fuel vapor tubes/hoses as necessary. If EVAP canister is cracked or smashed, GO to Powertrain/Engine System Group, Evaporative Emission Section in the Workshop Manual. If components are replaced, GO to HW42 . For Escort/Tracer, Mustang, Thunderbird/Cougar, Ranger, Aerostar:

GO to HW11 .

All Others:

GO to HW9 .

HW9 CHECK FOR VPWR VOLTAGE TO EVAP CANISTER PURGE VALVE
Disconnect EVAP canister purge valve harness connector.
Key on, engine off.
Measure VPWR circuit voltage at EVAP canister purge valve harness connector to battery negative post.
Key off.
Was the voltage greater than 10.5 volts?
Yes No
GO to HW10 . REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test.

HW10 CHECK FOR INTAKE MANIFOLD VACUUM AT THE EVAP CANISTER WHILE ELECTRICALLY CYCLING THE EVAP CANISTER PURGE VALVE
Install breakout box, connect PCM to breakout box.
Disconnect fuel vapor hose to EVAP canister purge valve at EVAP canister.
Install a vacuum gauge to open end of fuel vapor hose.
Start engine.
Idle engine for 5 minutes.
Observe the vacuum gauge. Reading must be near 0 kPa (0 in-Hg).
Connect a jumper between PCM test pin 56 and PCM test pin 51 or 103, while engine is still running.
Idle the engine for additional 5 to 10 minutes.
Observe the vacuum gauge.
Key off.
Did the vacuum reading change from near 0 kPa (0 in-Hg) to 33.77 kPa (10 in-Hg) or greater with addition of jumper?
Yes No
REMOVE vacuum gauge. INSPECT the fuel vapor tubes/hoses between the EVAP canister and the EVAP canister purge valve and between the EVAP canister purge valve and the intake manifold for small cracks, splits or holes. REPAIR as necessary. RESTORE vehicle. GO to HW11 . REMOVE vacuum gauge. LEAVE the fuel vapor hose from EVAP canister disconnected.

For vacuum readings within 20.26 kPa (6 in-Hg)-33.77 kPa (10 in-Hg):

GO to HW12 .

For vacuum readings less than 20.26 kPa (6 in-Hg):

GO to HW13 .

HW11 CHECK EVAP CANISTER
Disconnect fuel vapor hose to EVAP canister purge valve at EVAP canister.
Check for contamination or blockages at all ports on EVAP canister (to the fuel tank, to the EVAP canister purge valve and to the atmosphere).
Is a fault indicated?
Yes No
REPAIR EVAP canister. GO to Powertrain/Engine System Group, Evaporative Emission Section in the Workshop Manual. RESTORE vehicle. If components are replaced, GO to HW42 . GO to HW12 .

HW12 CHECK FOR FUEL VAPOR HOSE LEAK BETWEEN EVAP CANISTER PURGE VALVE AND EVAP CANISTER
Disconnect other end of fuel vapor hose from EVAP canister at EVAP canister purge valve.
Plug open end of fuel vapor hose at EVAP canister.
Install a hand vacuum pump to open end of fuel vapor hose at EVAP canister purge valve.
Apply 53 kPa (16 in-Hg) of vacuum with vacuum pump.
Does the vacuum pump hold the vacuum?
Yes No
REMOVE plug in hose. GO to HW13 . REPLACE damaged fuel vapor hose. RESTORE vehicle. GO to HW42 .

HW13 CHECK FOR FUEL VAPOR HOSE BLOCKAGE BETWEEN EVAP CANISTER PURGE VALVE AND EVAP CANISTER
Disconnect other end of fuel vapor hose from EVAP canister at EVAP canister purge valve.
Install a hand vacuum pump to open end of fuel vapor hose at EVAP canister purge valve.
Apply 53 kPa (16 in-Hg) of vacuum with vacuum pump.
Does the vacuum pump hold the vacuum?
Yes No
REMOVE vacuum pump. REPAIR or STRAIGHTEN fuel vapor hose as necessary. RESTORE vehicle. GO to HW42 . REMOVE vacuum pump.

For Escort/Tracer, Mustang, Thunderbird/Cougar, Ranger, Aerostar:

RECONNECT fuel vapor hose at EVAP canister. LEAVE other end of fuel vapor hose disconnected at EVAP canister purge valve. GO to HW17 .

All Others:

RECONNECT fuel vapor hose between EVAP canister and EVAP canister purge valve. GO to HW14 .

HW14 CHECK FOR FILTER CONTAMINATION OR DAMAGE TO THE EVAP CANISTER PURGE VALVE

Disconnect vacuum line from input vacuum port to intake manifold on EVAP canister purge valve. (Refer to EVAP canister purge valve vacuum schematic at the beginning of this Pinpoint Test.)
Install a hand vacuum pump to input vacuum port on EVAP canister purge valve.
Apply 48-52 kPa (10-15 in-Hg) of vacuum to EVAP canister purge valve.
Does the EVAP canister purge valve hold vacuum or show a very slow release of vacuum to atmosphere?
Yes No
REPAIR EVAP canister purge valve filter blockage or REPLACE EVAP canister purge valve. RESTORE vehicle. GO to HW42 . REMOVE vacuum pump. GO to HW15 .

HW15 CHECK FOR INTAKE MANIFOLD VACUUM AT VMV: BOTH INPUT PORT VACUUM HOSE AND FUEL VAPOR HOSE
EVAP canister purge valve electrically connected.
Disconnect both input port vacuum and fuel vapor hoses from intake manifold vacuum source and fuel vapor ports at EVAP canister purge valve. (Refer to the EVAP canister purge valve vacuum schematic at the beginning of this pinpoint test.)
Install a vacuum gauge (two gauges or one gauge at a time) to open end of input port vacuum hose and open end of the fuel vapor hose at EVAP canister purge valve.
Start engine.
Are both vacuum gauge readings greater than 33.77 kPa (10 in-Hg)?
Yes No
LEAVE input port vacuum and fuel vapor hoses to the intake manifold at EVAP canister purge valve disconnected. GO to HW16 . ISOLATE causes of missing intake manifold vacuum. REPAIR partially unconnected hoses or kinked/blocked hoses to intake manifold. REMOVE vacuum gauge(s). RESTORE vehicle. GO to the Powertrain/Engine Group in the Workshop Manual for base engine vacuum loss. COMPLETE PCM Reset to clear DTCs. GO to HW42 .

HW16 CHECK FOR INPUT PORT VACUUM HOSE AND FUEL VAPOR HOSE RESTRICTIONS BETWEEN EVAP CANISTER PURGE VALVE AND INTAKE MANIFOLD
Disconnect input port vacuum hose and fuel vapor hose from EVAP canister purge valve at intake manifold (other end of hoses are already disconnected).
Install a hand vacuum pump to one end of each completely disconnected hose from EVAP canister purge valve to intake manifold.
Apply 53 kPa (16 in-Hg) of vacuum with vacuum pump.
Observe the vacuum reading for 30 seconds.
Does the vacuum bleed off immediately?
Yes No
REMOVE vacuum pump. CORRECT minor concerns with input vacuum hose and fuel vapor hose between EVAP canister purge valve and intake manifold. If hoses were OK, REPLACE damaged EVAP canister purge valve. RESTORE vehicle. GO to HW42 . REMOVE vacuum pump. REMOVE blockages or minor kinks in input vacuum hose and fuel vapor hose between EVAP canister purge valve and intake manifold. RESTORE vehicle. DRIVE vehicle. GO to HW42 .

HW17 CHECK VPWR VOLTAGE TO EVAP CANISTER PURGE VALVE

Disconnect EVAP canister purge valve harness connector.
Key on, engine off.
Measure VPWR circuit voltage at EVAP canister purge valve harness connector to battery negative post.
Key off.
Was voltage greater than 10.5 volts?
Yes No
GO to HW18 . REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test.

HW18 CHECK EVAP CANISTER PURGE VALVE STUCK OPEN CONDITION OR PF SENSOR DAMAGE
Disconnect fuel vapor hose from intake manifold at PF sensor.
Reconnect the EVAP canister purge valve (electrically).
Install a hand-held vacuum pump to intake manifold side of PF sensor.
Apply 53 kPa (16 in-Hg) of vacuum to open end of PF sensor.
Does the EVAP canister purge valve-PF sensor assembly hold vacuum for 20 seconds?
Yes No
LEAVE the vacuum pump connected. GO to HW19 . If PF sensor housing is cracked, REPLACE PF sensor. Otherwise, REPLACE fuel vapor hose between EVAP canister purge valve and PF sensor. If fuel vapor hose was OK, REPLACE EVAP canister purge valve. RESTORE vehicle. GO to HW42 .

HW19 CHECK HOSE BLOCKAGE - EVAP CANISTER PURGE VALVE STUCK CLOSED CONDITION
Connect scan tool.
Apply 53 kPa (16 in-Hg) of vacuum to open end of PF sensor.
Key on, engine off.
Access Output Test Mode on the scan tool to cycle EVAP canister purge valve.
Key off.
Did the EVAP canister purge valve open and vacuum reading on the vacuum pump drop (air passes freely) when commanding the output on?
Yes No
REMOVE vacuum pump. GO to HW20 . REMOVE the vacuum pump. REMOVE blockages in fuel vapor hose between EVAP canister purge valve and PF sensor. If OK, REPLACE EVAP canister purge valve. RESTORE vehicle. GO to HW42 .

HW20 CHECK INTAKE MANIFOLD VACUUM TO PF SENSOR
Install a vacuum gauge to the open end of fuel vapor hose (intake manifold side) at PF sensor.
Start engine.
Observe vacuum gauge at idle (for Escort/Tracer application observe vacuum gauge reading at part throttle).
Key off.
Was the vacuum gauge reading greater than 33.77 kPa (10 in-Hg) with engine running?
Yes No
CHECK for small vacuum leaks between PF sensor and intake manifold. REPAIR as necessary. RESTORE vehicle. DRIVE vehicle. GO to HW42 . REMOVE blockage, RECONNECT loose fuel vapor hose or REPLACE cracked, split fuel vapor hose between the PF sensor and intake manifold. GO to HW42 . If DTC P1443 is still present, GO to HW21 .

All others:

RETURN to Section 3A , Symptom Charts.

HW21 CHECK EVAP CANISTER PURGE VALVE RESISTANCE
Disconnect EVAP canister purge valve.
Measure EVAP canister purge valve resistance.
Is the resistance between 30 and 90 ohms?
Yes No
GO to HW22 . REPLACE damaged EVAP canister purge valve. RESTORE vehicle. GO to HW42 .

HW22 CHECK EVAP CANISTER PURGE CIRCUIT FOR SHORT TO VPWR IN HARNESS
Install breakout box, leave PCM disconnected.
Measure resistance between PCM test pin 67 or PCM test pin 56 and PCM test pin 71.
Is resistance greater than 10,000 ohms?
Yes No
REPLACE PCM. RESTORE vehicle.

Access the EVAPPDC PID on the scan tool. DRIVE vehicle (including a steady accelerator speed over 80 km/h (50 mph) until the EVAPPDC PID shows 75 percent duty cycle). Then maintain approximate speed until duty cycle reaches zero percent. After additional two minute drive, bring vehicle to an idle. RERUN Quick Test. REPAIR short circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs.

Access the EVAPPDC PID on the scan tool. DRIVE vehicle (including a steady accelerator speed over 80 km/h (50 mph) until the EVAPPDC PID shows 75 percent duty cycle). Then maintain approximate speed until duty cycle reaches zero percent. After additional two minute drive, bring vehicle to an idle. RERUN Quick Test.

HW23 CHECK EVAPORATIVE EMISSION SYSTEM LEAK THROUGH EVAPORATIVE EMISSION SERVICE PORT

Odors in the engine compartment or near the exhaust system and stalls can be associated to the evaporative emission system.

Possible causes:

After-market parts and accessories not conforming to evaporative system specifications.
Leaks in the evaporative emission system.
Blockages in the evaporative emission system.
Remove atmospheric vent cap (blue or black) on EVAP canister(s) or canister vent line.
Plug (or tape) open vent on EVAP canister(s).
Disconnect and plug fuel vapor hose to PF sensor (or EVAP canister purge valve) from intake manifold at the intake manifold vacuum source.
Locate evaporative emission test port (marked EVAPORATIVE SERVICE PORT) between EVAP canister purge valve and EVAP canister. If vehicle does not have a test port, GO to Pinpoint Test step HW24 .
Access the Rotunda Evaporative Emission System Tester 134-00056 or equivalent, including the compressed gas source (nitrogen or argon) and pressure regulator.
Perform a Tester Self-Test using the instructions provided with the Tester Kit.
Regulate the gas pressure on the Tester to 6.74 kPa (27 in-H2 O).
Install the Rotunda Evaporative Emission System Tester to the test port and follow the system leak test instructions provided with the Tester Kit.
If the pressure is not between 6.46 and 6.97 kPa (26 and 28 in-H2 O), use the ultra-sonic leak detector provided with the Tester Kit to check for leakage at the vehicle's fuel filler cap and filler pipe assembly.
Is a leak indicated?
Yes No
REMOVE and VERIFY fuel filler cap according to original equipment specifications. REPLACE damaged fuel filler cap. REINSTALL fuel filler cap and TIGHTEN cap only one eighth turn so that cap initially clicks by sound or touch. REPEAT evaporative emission system leak test using Tester. If the leak is still present, REPAIR or REPLACE fuel tank, fuel filler pipe, fuel vapor valve or fuel vapor hose between fuel tank and EVAP canister as necessary. RESTORE vehicle. VERIFY a symptom no longer exists. GO to HW24 .

HW24 CHECK EVAPORATIVE EMISSION SYSTEM USING ROTUNDA EVAPORATIVE EMISSION SYSTEM TESTER
Remove the fuel filler cap.
Install the Rotunda Evaporative Emission System Tester 134-00056 or equivalent, including the compressed gas (nitrogen or argon) and pressure regulator. Tester kit contains all required adapters (Schrader valve and fuel filler cap per vehicle application).
Key on, engine off.
For Mustang only: cycle the valve open through output test mode with the scan tool (or disconnect valve harness connection and energize valve using a voltage source).
Pressurize the vehicle evaporative emission system at 6.74 kPa (27 in.-H2 O) using the Evaporative Emission System Tester and the instructions that come with the tester.
Is a system leak indicated by the tester red light on?
Yes No
ALLOW the two-position control on the tester to provide a continuing flow of the gas to the closed evaporative emission system. MAINTAIN 6.74 kPa (27 in.-H2O) pressure on the system (monitor tester pressure gauges). GO to HW25 . REMOVE Evaporative Emission System Leak Tester. COMPLETE PCM Reset to clear DTCs. Access the EVAPPDC PID on the scan tool. DRIVE vehicle (including a steady accelerator speed over 80 km/h (50 mph) until the EVAPPDC PID shows 75 percent duty cycle). Then maintain approximate speed until duty cycle reaches zero percent. After additional two minute drive, bring vehicle to an idle. RERUN Quick Test. VERIFY a symptom no longer exists.

HW25 CHECK FOR FUEL VAPOR HOSE RESTRICTIONS BETWEEN EVAP CANISTER PURGE VALVE, FUEL TANK AND EVAP CANISTER
Key on, engine off.
Disconnect and plug the fuel vapor hose from the EVAP canister(s) at EVAP canister purge valve.
Reinitiate pressurizing of vehicle evaporative emission system using the Rotunda Evaporative Emission System Tester. Refer to Pinpoint Test Step HW24 for pressurizing instructions.
When pressure on the evaporative emission system is stabilized close to 6.74 kPa (27 in-H2O), record the reading.
Remove the plug at the fuel vapor hose to EVAP canister at the EVAP canister purge valve.
Observe pressure gauges on tester.
Does the pressure immediately drop?
Yes No
REMOVE plugs. REINSTALL the dust cap (blue or black) on EVAP canister or canister vent line at canister. RESTORE vehicle. GO to HW42 . REMOVE blockages and STRAIGHTEN fuel vapor tubes/hoses between fuel tank, EVAP canister purge valve and EVAP canister(s). GO to the Powertrain/Engine System Group, Evaporative Emission section in the Workshop Manual for blockage concerns. REMOVE plugs. REINSTALL the dust cap (blue or black) on EVAP canister. RESTORE the vehicle. GO to HW42 .

Click to expand...