DTC P1289 [YF (2.0L Zetec)]

id0102d0872700

DTC P1289

Cylinder head temperature sensor circuit high input

DETECTION CONDITION

• If the PCM detects the cylinder head temperature sensor voltage is above threshold while the engine running to on, the PCM determines that the cylinder head temperature sensor circuit has malfunction.

POSSIBLE CAUSE

• Cylinder head temperature sensor malfunction
• Poor connection of the cylinder head temperature sensor and/or the PCM connectors
• Short to power circuit between the cylinder head temperature sensor terminal 1 and the PCM connector terminal 38
• Open circuit in wiring harness between the cylinder head temperature sensor terminal 1 and the PCM terminal 38
• Open circuit in wiring harness between the cylinder head temperature sensor terminal 2 and the PCM terminal 91
• 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 CYLINDER HEAD TEMPERATURE SENSOR CONNECTOR
• Turn the ignition switch off.
• Verify that the cylinder head temperature sensor connector is connected securely.
• Is connector normal?
Yes
Go to the next step.
No
Connect the connector securely, then go to Step 10.
4
INSPECT POOR CONNECTION OF CYLINDER HEAD TEMPERATURE SENSOR CONNECTOR
• Disconnect the cylinder head temperature sensor 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 10.
No
Go to the next step.
5
INSPECT CYLINDER HEAD TEMPERATURE SENSOR
• Perform cylinder head temperature sensor inspection.
• Is cylinder head temperature sensor normal?
Yes
Go to the next step.
No
Replace the TP sensor, then go to Step 10.
6
INSPECT CYLINDER HEAD TEMPERATURE SENSOR SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY
• Turn the ignition switch to the ON position (engine off).
• Measure the voltage between the cylinder head temperature sensor terminal 1 and body ground.
• Is the voltage above 4.6 V?
Yes
Repair or replace short to power supply. Then, go to Step 10.
No
Go to the next step.
7
VERIFY CYLINDER HEAD TEMPERATURE SIGNAL CIRCUIT FOR OPEN CIRCUIT
• Turn the ignition switch off.
• Inspect for continuity between the cylinder head temperature sensor terminal 1 (wiring harness-side) and the PCM terminal 38.
• Is there continuity?
Yes
Go to the next step.
No
Repair or replace the wiring harness, then go to Step 10.
8
VERIFY CYLINDER HEAD TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN CIRCUIT
• Inspect for continuity between the cylinder head temperature sensor terminal 2 and body ground.
• Is there continuity?
Yes
Repair or replace open circuit in wiring harness between the cylinder head temperature sensor terminal 2 (wiring harness-side) and the PCM terminal 91 (wiring harness-side). Then, go to Step 10.
No
Go to the next step.
9
INSPECT PCM CONNECTOR
• Disconnect the PCM connector.
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Is there any malfunction?
Yes
Repair terminal, then go to the next step.
No
Go to the next step.
10
VERIFY TROUBLESHOOTING OF DTC P1289 COMPLETED
• Make sure to reconnect all disconnected connectors.
• Clear the DTC from the PCM memory using the WDS or equivalent.
• Start the engine.
• Is same DTC present?
Yes
Replace the PCM, then go to the next step.
No
Go to the next step.
11
VERIFY AFTER REPAIR PROCEDURE
• Perform "AFTER REPAIR PROCEDURE".
• Are any DTC present?
Yes
Go to the applicable DTC troubleshooting.
No
Troubleshooting completed.