DTC P1504 [YF (2.0L Zetec)]

id0102d0826000

DTC P1504

IAC valve circuit

DETECTION CONDITION

• This DTC is set when the PCM detects an electrical load failure on the IAC output circuit

POSSIBLE CAUSE

• IAC valve circuit malfunction
• Short to ground in wiring harness between IAC valve terminal 1 and main relay terminal 87
• Short to ground in wiring harness between IAC valve terminal 2 and PCM terminal 83
• Open circuit in wiring harness between IAC valve terminal 1 and main relay terminal 87
• Open circuit in wiring harness between IAC valve terminal 2 and PCM terminal 83
• Short to power supply in wiring harness between IAC valve terminal 1 and main relay terminal 87
• Short to power supply in wiring harness between IAC valve terminal 2 and PCM terminal 83
• Poor connection of IAC valve connector or PCM connector
• PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
• Has FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2
VERIFY RELATED REPAIR INFORMATION AVAILABILITY
• Verify related service repair information availability.
• Is any related repair information available?
Yes
Perform repair or diagnosis according to the available repair information.
• If the vehicle is not repaired, go to the next step.
No
Go to the next step.
3
INSPECT POOR CONNECTION OF IAC VALVE CONNECTOR
• Turn the ignition switch off.
• Disconnect IAC valve connector.
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Is there any malfunction?
Yes
Repair or replace the terminal, then go to Step 9.
No
Go to the next step.
4
INSPECT IAC VALVE ELECTRICAL MALFUNCTION
• Inspect the IAC valve.
• Is IAC valve normal?
Yes
Go to the next step.
No
Replace IAC valve, then go to Step 9.
5
INSPECT CONTROL CIRCUIT FOR SHORT TO POWER
• Turn the ignition switch to the ON position (Engine off).
• Measure voltage between IAC valve terminal 2 (wiring harness-side) and body ground:
• Is the voltage B+?
Yes
Repair or replace wiring harness, then go to Step 9.
No
Go to the next step.
6
INSPECT CONTROL CIRCUIT FOR SHORT TO GROUND
• Turn the ignition switch off.
• Inspect for continuity between following terminals (wiring harness-side) and body ground:
- IAC valve terminal 1
- IAC valve terminal 2
• Is there continuity?
Yes
Repair or replace the wiring harness, then go to Step 9.
No
Go to the next step.
7
INSPECT POOR CONNECTION OF PCM CONNECTOR
• Turn the ignition switch off.
• Disconnect the PCM connector.
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Is there any malfunction?
Yes
Repair the terminal, then go to Step 9.
No
Go to the next step.
8
INSPECT CONTROL CIRCUIT MALFUNCTION FOR OPEN CIRCUIT
• Inspect for continuity following terminals (wiring harness-side):
- Between IAC valve terminal 1 and main relay terminal 87
- Between IAC valve terminal 2 and PCM terminal 83
• Is there continuity?
Yes
Repair or replace the wiring harness, then go to the next step.
No
Go to the next step.
9
VERIFY TROUBLESHOOTING OF DTC P1504 COMPLETED
• Make sure to reconnect all disconnected connectors.
• Clear the DTC using the WDS or equivalent.
• Start the engine.
• Is the same DTC present?
Yes
Replace the PCM, then go to the next step.
No
Go to the next step.
10
VERIFY AFTER REPAIR PROCEDURE
• Perform the "After Repair Procedure".
• Are any DTC present?
Yes
Go to the applicable DTC troubleshooting.
No
Troubleshooting completed.