DL - Test
DL: Cylinder Head Temperature (CHT) Sensor
DL: Introduction DL - Introduction
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DL1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS) P0116, P0119, P0128, P1285, P1289, P1290 OR P1299
Are any of the following DTCs present during PCM or transaxle control module (TCM) self-test: P0116, P0119, P0128, P1285, P1288, P1289, P1290 or P1299?
YES
For continuous memory DTC P0116, GO to DL24
.
For continuous memory DTC P0119, GO to DL15
.
For continuous memory DTC P0128, GO to DL22
.
For DTC P1285, GO to DL18
.
For DTC P1288, GO to DL2
.
For KOEO and KOER DTCs P1289 or P1290, GO to DL7
.
For continuous memory DTCs P1289 or P1290, GO to DL15
.
For KOER and continuous memory DTC P1299, GO to DL21.
NO
Unable to duplicate or identify the concern at this time.
RETURN to Symptom Charts Symptom Related Diagnostic Procedures
, Symptom Chart, for further direction.
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DL2 SELF-TEST DTC P1288: 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.
Note: The DTC indicates the temperature sensor is out of self-test range. The engine is not at normal operating temperature.
- Check the vehicle coolant level.
Is the cooling system OK?
YES
GO to DL3.
NO
REFER to Engine Cooling for cooling system diagnostics.
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DL3 CHECK IF THE ENGINE STARTS
- Attempt to start the engine.
Does the engine start and run normally?
YES
GO to DL6.
NO
GO to DL4.
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DL4 CHECK THE RESISTANCE OF THE CHT SENSOR WITH THE ENGINE OFF
Note: Refer to the chart at the beginning of this test for the resistance specifications.
- Key in OFF position.
- CHT Sensor connector disconnected.
- Measure the resistance between:
Is the resistance within specification?
YES
CONNECT the CHT sensor.
GO to DL5.
NO
INSTALL a new CHT sensor. REFER to Electronic Engine Controls.
CLEAR the DTCs. REPEAT the self-test.
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DL5 CHECK IF THE VEHICLE ENGINE STARTS NORMALLY
- Attempt to start the engine.
Does the engine start?
YES
GO to DL6.
NO
GO to Pinpoint Test A A - Introduction.
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DL6 CHECK THE OPERATION OF THE CHT SENSOR
- Start the engine using the engine running diagnostic mode. Refer to Diagnostic Modes Diagnostic Modes.
- Run the engine until it reaches normal operating temperature.
- Carry out the KOEO self-test.
Is DTC P1288 present?
YES
GO to DL20.
NO
The engine temperature was not stabilized.
REPAIR any other DTCs as necessary.
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DL7 DTCS P1289 OR P1290: ACCESS THE CHT PID AND CHECK THE VOLTAGE
- Key ON, engine OFF.
- Access the PCM and monitor the CHT PID.
Is the voltage less than 0.2 V?
YES
GO to DL8.
NO
GO to DL9.
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DL8 CHECK FOR A GROUNDED CIRCUIT
- Key in OFF position.
- CHT Sensor connector disconnected.
- Access the PCM and monitor the CHT PID.
Is the voltage greater than 4.6 V?
YES
INSTALL a new CHT sensor. REFER to Electronic Engine Controls.
CLEAR the DTCs. REPEAT the self-test.
NO
GO to DL14.
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DL9 CHECK FOR A VREF SHORT
- Key in OFF position.
- CHT Sensor connector disconnected.
- Connect a 5 amp fused jumper wire between the following:
- Key ON, engine OFF.
- Access the PCM and monitor the CHT PID.
Is the voltage less than 0.2 V?
YES
REMOVE the jumper.
GO to DL11.
NO
REMOVE the jumper.
GO to DL10.
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DL10 CHECK THE CHT CIRCUIT FOR A SHORT TO VOLTAGE
- CHT Sensor connector disconnected.
- Key ON, engine OFF.
- Measure the voltage between:
Is the voltage greater than 5.5 V?
YES
REPAIR the circuit.
CHECK the CHT sensor for damage.
CLEAR the DTCs. REPEAT the self-test.
GO to DL11.
NO
GO to DL11.
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DL11 CHECK THE RESISTANCE OF THE CHT SENSOR WITH THE ENGINE OFF
Note: Refer to the chart at the beginning of this test for the resistance specifications.
- Key in OFF position.
- CHT Sensor connector disconnected.
- Measure the resistance between:
Is the resistance within specification?
YES
GO to DL12.
NO
INSTALL a new CHT sensor. REFER to Electronic Engine Controls.
CLEAR the DTCs. REPEAT the self-test.
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DL12 CHECK THE SIGNAL AND SIGRTN CIRCUITS FOR AN OPEN IN THE HARNESS
- PCM connector disconnected.
- Measure the resistance between:
Are the resistances less than 5 ohms?
YES
GO to DL13.
NO
REPAIR the circuit.
CLEAR the DTCs. REPEAT the self-test.
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DL13 CHECK THE SENSOR SIGNAL FOR A SHORT TO VREF
- Key in OFF position.
- PCM connector disconnected.
- Measure the resistance between:
Is the resistance greater than 10K ohms?
YES
GO to DL26.
NO
REPAIR the circuit.
CLEAR the DTCs. REPEAT the self-test.
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DL14 CHECK THE SENSOR SIGNAL FOR A SHORT TO GROUND
- Key in OFF position.
- PCM connector disconnected.
- Measure the resistance between:
- Measure the resistance between:
Is the resistance greater than 10K ohms?
YES
GO to DL26.
NO
REPAIR the circuit.
CLEAR the DTCs. REPEAT the self-test.
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DL15 DTCS P0119, P1289 AND P1290: INTERMITTENT CHECK
- Key ON, engine OFF.
- Access the PCM and monitor the CHT 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 voltage reading?
YES
DISCONNECT and INSPECT the connector.
If OK, INSTALL a new CHT sensor. REFER to Electronic Engine Controls.
CLEAR the DTCs. REPEAT the self-test.
NO
GO to DL16.
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DL16 CHECK THE ELECTRONIC ENGINE CONTROL (EEC) WIRING HARNESS
- Access the PCM and monitor the CHT PID.
- While observing the PID, wiggle, shake, and bend small sections of the wiring harness working from the sensor to the PCM.
Is there a large change in the voltage reading?
YES
ISOLATE the concern.
REPAIR as necessary.
NO
GO to DL17.
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DL17 CHECK THE PCM AND VEHICLE HARNESS CONNECTORS
- PCM connector disconnected.
- CHT Sensor connector disconnected.
Are the connectors and terminals OK?
YES
Unable to duplicate or identify the concern at this time.
DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. GO to Diagnostic Trouble Code (DTC) Charts and Descriptions Diagnostic Trouble Code Descriptions.
NO
REPAIR as necessary.
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DL18 SELF-TEST DTC P1285: EARLY WARNING OF ENGINE OVERHEAT CONDITION
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.
Note: An engine overheat condition was sensed by the CHT sensor.
Note: If the electric cooling fan does not operate, return to Diagnostic Trouble Code (DTC) Charts and Descriptions Diagnostic Trouble Code Descriptions for electric cooling fan DTC. or Symptom Charts Symptom Related Diagnostic Procedures , Symptom Charts for symptom diagnosis.
- 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
For CHT sensor check.
GO to DL19.
NO
REFER to Engine Cooling for cooling system diagnostics.
REPAIR as necessary.
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DL19 CHECK THE OPERATION OF THE CHT SENSOR
- Start the engine using the engine running diagnostic mode. Refer to Diagnostic Modes Diagnostic Modes.
- Run the engine until it reaches normal operating temperature.
- Carry out the KOEO self-test.
Is DTC P1285 present?
YES
GO to DL20.
NO
An engine overheat temperature was not detected.
REPAIR any other DTCs as necessary.
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DL20 CHECK THE RESISTANCE OF THE CHT SENSOR
Note: Refer to the chart at the beginning of this test for the resistance specifications.
- The vehicle must be at normal operating temperature.
- Key in OFF position.
- CHT Sensor connector disconnected.
- Measure the resistance between:
Is the resistance within specification?
YES
GO to DL26.
NO
INSTALL a new CHT sensor. REFER to Electronic Engine Controls.
CLEAR the DTCs. REPEAT the self-test.
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DL21 SELF-TEST DTC P1299: INDICATES AN ENGINE OVERHEAT CONDITION
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.
- Check the engine coolant level.
Is the engine coolant fill level correct?
YES
REFER to Engine Cooling to diagnose the engine overheat condition.
NO
REFER to Engine Cooling to diagnose the coolant loss condition.
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DL22 SELF-TEST DTC P0128: CHECK THE ENGINE COOLANT LEVEL
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.
Note: DTC P0128 indicates the engine coolant temperature has not achieved the required engine operation temperature level, since start-up within a specified amount of time.
- Check the engine coolant level.
Is the engine coolant fill level correct?
YES
GO to DL23.
NO
REFER to Engine Cooling to diagnose the coolant loss condition.
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DL23 CHECK THE SENSOR OPERATION
- Start the engine using the engine running diagnostic mode. Refer to Diagnostic Modes Diagnostic Modes.
- Run the engine until it reaches normal operating temperature.
- Access the PCM and monitor the CHT PID.
Is the temperature greater than 77° C (170.6°F)?
YES
Unable to duplicate or identify the concern at this time.
NO
REFER to Engine Cooling to diagnose why the engine does not reach operating temperature.
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DL24 DTC P0116: CHECK THE RESISTANCE OF THE CHT SENSOR WITH THE ENGINE OFF
Note: Verify the engine temperature is at ambient room temperature before continuing with this test. A soak period of 6 hours may be required. Refer to Diagnostic Trouble Code (DTC) Charts and Descriptions Diagnostic Trouble Code Descriptions for information concerning DTC P0116.
Note: Refer to the chart at the beginning of this test for the resistance specifications.
- Key in OFF position.
- CHT Sensor connector disconnected.
- Measure the resistance between:
Is the resistance within specification?
YES
CONNECT the CHT.
GO to DL25.
NO
INSTALL a new CHT sensor.
REFER to Electronic Engine Controls.
CLEAR the DTCs. REPEAT the self-test.
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DL25 DTC P0116: CHECK THE RESISTANCE OF THE CHT SENSOR
Note: Verify the engine is at normal operating temperature before taking the CHT reading.
Note: Refer to the chart at the beginning of this test for the resistance specifications.
- Start the engine using the engine running diagnostic mode. Refer to Diagnostic Modes Diagnostic Modes.
- Run the engine until the engine temperature stabilizes.
- Key in OFF position.
- CHT Sensor connector disconnected.
- Measure the resistance between:
Is the resistance within specification?
YES
Unable to duplicate or identify the concern at this time.
NO
INSTALL a new CHT sensor.
REFER to Electronic Engine Controls.
CLEAR the DTCs. REPEAT the self-test.
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DL26 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Visually inspect for:
- pushed out pins
- corrosion
- Connect all the PCM connectors and make sure they seat correctly.
- Carry out the PCM self-test and verify the concern is still present.
Is the concern still present?
YES
INSTALL a new PCM.
REFER to Flash Electrically Erasable Programmable Read Only Memory (EEPROM) Flash Electrically Erasable Programmable Read Only Memory (EEPROM).
NO
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.