Test Procedure
- DL1 CHECK FOR DTCS
Are DTCs P0116, P0119, P0125, P0128, P017C, P017D, P017E, P1021, P1022, P1023, P1024, P1025, P1026, P1285, P1289, P128A, or P1290 present?
Yes No GO to DL2. For temperature warning indicator lamp or gauge (applications with CHT sensor only) symptom, GO to DL13.
For all others, RETURN to SYMPTOM CHARTS for further direction. - DL2 CHECK THE COOLING SYSTEM WARNING: TO AVOID PERSONAL INJURY DO NOT UNSCREW THE COOLANT PRESSURE RELIEF CAP WHILE THE ENGINE IS OPERATING OR HOT. THE COOLING SYSTEM IS UNDER PRESSURE. STEAM AND HOT LIQUID CAN COME OUT FORCEFULLY WHEN THE CAP IS LOOSENED SLIGHTLY. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY.NOTE: The DTCs P0125, P0128, P101F, P1025, or P1288 indicate the engine coolant temperature has not achieved the required engine operation temperature level, since start up within a specified amount of time.
- Check the cooling system for:
- correct coolant level
- internal or external coolant leaks
- blockage of the radiator
- cooling fan operation
Is the cooling system OK?
Yes No For DTCs P0125, P0128, P101F, P1025, or P1288, GO to DL12.
For all others, GO to DL3.REFER to the appropriate Engine Cooling article to diagnose a cooling system concern.
REPAIR as necessary.
Clear the PCM DTCs. REPEAT the self-test. - Check the cooling system for:
- DL3 CHECK THE RESISTANCE OF THE CHT SENSOR WITH THE ENGINE OFF NOTE: Refer to the CYLINDER HEAD TEMPERATURE (CHT) And CHT2 Sensor Expected Values chart for the resistance specifications.
- Ignition OFF.
- For the CHT2 sensor,
CHT2 Sensor connector disconnected.
Measure the resistance between:(+) CHT2 Sensor Connector, Component Side (-) CHT2 Sensor Connector, Component Side CHT2 SIGRTN For all others,
CHT Sensor connector disconnected.
Measure the resistance between:
(+) CHT Sensor Connector, Component Side (-) CHT Sensor Connector, Component Side CHT SIGRTN Is the resistance within specification?
Yes No GO to DL4. INSTALL a new CHT sensor.
REFER to the appropriate Electronic Engine Controls article.
Clear the PCM DTCs. REPEAT the self-test. - DL4 CHECK FOR AN OPEN CIRCUIT
- Ignition OFF.
- PCM connector disconnected.
- For the CHT2 sensor,
- Measure the resistance between:
(+) PCM Connector, Harness Side (-) CHT2 Sensor Connector, Harness Side CHT2 CHT2 SIGRTN SIGRTN - For all others,
- Measure the resistance between:
(+) PCM Connector, Harness Side (-) CHT Sensor Connector, Harness Side CHT CHT SIGRTN SIGRTN Are the resistances less than 5 ohms?
Yes No GO to DL5. REPAIR the open circuit. Clear the PCM DTCs.
REPEAT the self-test. - DL5 CHECK FOR A SHORT TO GROUND
- For the CHT2 sensor,
- Measure the resistance between:
(+) CHT2 Sensor Connector, Harness Side (-) CHT2 Ground - For all others,
- Measure the resistance between:
(+) CHT Sensor Connector, Harness Side (-) CHT Ground
Are the resistances greater than 10K ohms?
Yes No GO to DL6. REPAIR the short circuit. Clear the PCM DTCs.
REPEAT the self-test. - DL6 CHECK FOR A SHORT TO VOLTAGE
- Ignition ON, engine OFF.
- For the CHT2 sensor,
- Measure the voltage between:
(+) CHT2 Sensor Connector, Harness Side (-) CHT2 Ground - For all others,
- Measure the voltage between:
(+) CHT Sensor Connector, Harness Side (-) CHT Ground
Is any voltage present?
Yes No REPAIR the short circuit. Clear the PCM DTCs.
REPEAT the self-test.GO to DL7. - DL7 CHECK THE RESISTANCE OF THE CHT SENSOR NOTE: Refer to the CYLINDER HEAD TEMPERATURE (CHT) And CHT2 Sensor Expected Values chart for the resistance specifications.
- Ignition OFF.
- CHT Sensor connector connected.
- CHT2 Sensor connector connected.
- PCM connector connected.
- Run the engine until the engine temperature stabilizes.
- Ignition OFF.
- For the CHT2 sensor,
- CHT2 Sensor connector disconnected.
- Measure the resistance between:
(+) CHT2 Sensor Connector, Component Side (-) CHT2 Sensor Connector, Component Side CHT2 SIGRTN - For all others,
- CHT Sensor connector disconnected.
- Measure the resistance between:
(+) CHT Sensor Connector, Component Side (-) CHT Sensor Connector, Component Side CHT SIGRTN
Is the resistance within specification?
Yes No For the CHT2 sensor, GO to DL8.
For all others, GO to DL10.INSTALL a new CHT sensor.
REFER to the appropriate Electronic Engine Controls article.
Clear the PCM DTCs. REPEAT the self-test. - DL8 CHECK THE CHT2 SENSOR
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) CHT2 Sensor Connector, Harness Side (-) CHT2 Sensor Connector, Harness Side CHT2 SIGRTN - Observe the digital multi meter (DMM) for an indication of a concern while shaking, wiggling, and bending the CHT2 circuit between the CHT2 and the PCM. Note that voltage changes suddenly when a concern is detected.
Is a concern present?
Yes No REPAIR as necessary.
Clear the PCM DTCs. REPEAT the self-test.GO to DL9. - DL9 TEMPERATURE SENSOR CORRELATION NOTE: Cold soak the vehicle at ambient temperature for at least 6 hours while not in direct sunlight.NOTE: All PID's may not be available on all vehicles.
- Ignition OFF.
- CHT2 Sensor connector connected.
- Ignition ON, engine OFF.
- Access the PCM and monitor the AAT (TEMP), CHT (TEMP), CHT2 (TEMP), ECT (TEMP) and ECT1 (TEMP) PIDs.
Are the PID values within 16.67°C (30°F) of each other?
Yes No Unable to duplicate or identify the concern at this time.
GO to PINPOINT TEST Z .INSTALL a new CHT sensor.
REFER to the appropriate Electronic Engine Controls article.
Clear the PCM DTCs. REPEAT the self-test. - DL10 INTERMITTENT CHECK
- Ignition OFF.
- CHT Sensor connector connected.
- Ignition ON, engine OFF.
- Access the PCM and monitor the CHT (TEMP) PID.
- While observing the PID, carry out the following:
- Tap on the sensor to simulate road shock
- Wiggle the sensor connector
Is there a large change in the PID value?
Yes No REPAIR as necessary.
Clear the PCM DTCs. REPEAT the self-test.For DTC P1285, GO to DL11.
For all others, Unable to duplicate or identify the concern at this time.
GO to PINPOINT TEST Z . - DL11 CHECK THE CHT SENSOR OPERATION NOTE: The engine temperature warning indicator (gauge or lamp) is a warning system that gives the driver information during an engine overheating condition. The PCM monitors the CHT sensor and determines if fail-safe cooling mode is needed. If fail-safe cooling mode is needed, the PCM sends a controller area network (CAN) message to the instrument cluster to signal an overheating condition. This causes the instrument cluster indicator to illuminate and forces the temperature gauge to the H (hot) zone. DTC P1285 is stored in the PCM.
- Run the engine until the engine temperature stabilizes.
- Verify the radiator hoses are hot and the cooling system is pressurized.
- Carry out the PCM self-test.
Is DTC P1285 present?
Yes No REFER to the appropriate Engine Cooling article to diagnose the cooling system concern.
Clear the PCM DTCs. REPEAT the self-test.The system is operating correctly at this time. REPAIR any other DTCs as necessary.
Clear the PCM DTCs. REPEAT the self-test. - DL12 CHECK THE SENSOR OPERATION
- Run the engine until the engine temperature stabilizes.
- Verify the radiator hoses are hot and the cooling system is pressurized.
- Access the PCM and monitor the CHT (TEMP) PID.
- Record the PID value.
Is the PID temperature greater than 77 C (170.6 F)?
Yes No The system is operating correctly at this time.
Clear the PCM DTCs. REPEAT the self-test.REFER to the appropriate Engine Cooling article, to diagnose the engine not reaching normal operating temperature. REPAIR as necessary.
Clear the PCM DTCs. REPEAT the self-test. - DL13 ENGINE TEMPERATURE INDICATOR LAMP ON OR TEMPERATURE GAUGE INDICATES HOT WITH NO DTCS NOTE: For Engine Temperature Warning Indicator system problems, refer to the appropriate Instrument Cluster article.
- PCM connector disconnected.
- Ignition ON, engine OFF.
Does the engine temperature warning indicator lamp turn OFF (prove out) and/or the temperature gauge return to the normal zone with the PCM disconnected?
Yes No GO to DL14. REFER to the appropriate Instrument Cluster article to diagnose the incorrect temperature gauge. REPAIR as necessary.
Clear the PCM DTCs. REPEAT the self-test. - DL14 ENGINE OVERHEAT CONDITION INDICATED WARNING: TO AVOID PERSONAL INJURY DO NOT UNSCREW THE COOLANT PRESSURE RELIEF CAP WHILE THE ENGINE IS OPERATING OR HOT. THE COOLING SYSTEM IS UNDER PRESSURE. STEAM AND HOT LIQUID CAN COME OUT FORCEFULLY WHEN THE CAP IS LOOSENED SLIGHTLY. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY.
- Check the engine coolant level.
Is the engine coolant fill level correct?
Yes No REFER to the appropriate Engine Cooling article, to diagnose the engine overheating symptom. REPAIR as necessary.
Clear the PCM DTCs. REPEAT the self-test.REFER to the appropriate Engine Cooling article to diagnose the loss of coolant. REPAIR as necessary.
Clear the PCM DTCs. REPEAT the self-test.