Pinpoint Test DL: Cylinder Head Temperature (CHT) Sensor

NOTE: On a typical vehicle, the CHT sensor is located in the cylinder head and the CHT 2 sensor is located in the exhaust manifold.

Normal Operation and Fault Conditions

On applications that do not use an ECT sensor, the CHT sensor is used to determine the engine coolant temperature. To cover the entire temperature range of both the CHT and ECT sensors, the PCM has a dual switching resistor circuit on the CHT input. A graph showing the temperature switching from the COLD END line to the HOT END line, with increasing temperature and back with decreasing temperature is included. Note the temperature to voltage overlap zone. Within this zone it is possible to have either a COLD END or HOT END value at the same temperature. For example, at 90C (194F) the voltage could read either 0.60 volt or 3.71 volts. Refer to the table for the expected values.

Voltage values calculated for VREF = 5 volts. These values can vary by 15% due to sensor and VREF variations.

Refer to the DTC Fault Trigger Conditions.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
PCM P0116:00	Engine Coolant Temperature Sensor 1 Circuit Range/Performance: No Sub Type Information	Sets when the PCM detects the engine coolant temperature or cylinder head temperature value is higher than the calibrated value and could prevent one or more OBD monitors from completing. The PCM runs this logic after an engine off and a calibrated soak period (typically 6 hours). This soak period allows the intake air temperature and the engine coolant temperature or cylinder head temperature to stabilize and not differ by greater than a calibrated value. This DTC sets when all of the following conditions are met: The engine coolant temperature at engine start exceeds the intake air temperature at engine start by greater than a calibrated value, typically 17deg.C (30deg.F). The engine coolant temperature exceeds a calibrated value, typically 107deg.C (225deg.F). The fuel system, heated oxygen and misfire monitors have not completed. The calibrated time to set this DTC has expired. Make sure the intake air temperature and the engine coolant temperature or cylinder head temperature are similar when the engine is cold. Also make sure the ECT or CHT sensor and the actual engine operating temperatures are the same.
PCM P0119:00	Engine Coolant Temperature Sensor 1 Circuit Intermittent/Erratic: No Sub Type Information	Sets when the PCM detects the ECT circuit is intermittently open or shorted while the engine is running.
PCM P017C:00	Cylinder Head Temperature Sensor 'A' Circuit Low: No Sub Type Information	Sets when the PCM detects the CHT circuit is shorted to ground.The DTC P0117 may also be reported when this DTC sets. Either of these Diagnostic Trouble Codes (DTCs) illuminates the MIL.
PCM P017D:00	Cylinder Head Temperature Sensor 'A' Circuit High: No Sub Type Information	Sets when the PCM detects a CHT circuit concern is detected.The DTC P0118 may also be reported when this DTC sets. Either of these Diagnostic Trouble Codes (DTCs) illuminate the MIL.
PCM P017E:00	Cylinder Head Temperature Sensor 'A' Circuit Intermittent/Erratic: No Sub Type Information	Sets when the PCM detects the CHT circuit becomes intermittently open or short while the engine is running.
PCM P101F:00	Cylinder Head Temperature Sensor 1 Out Of Self Test Range: No Sub Type Information	This DTC sets when the CHT sensor is out of self-test range. The engine is not at a normal operating temperature.
PCM P1021:00	Cylinder Head Temperature Sensor 2 Circuit Range/Performance: No Sub Type Information	Sets when the PCM detects the cylinder head temperature value is higher than the calibrated value and could prevent one or more OBD monitors from completing. The PCM runs this logic after an engine off and a calibrated soak period (typically 6 hours). This soak period allows the intake air temperature and the cylinder head temperature to stabilize and not differ by greater than a calibrated value. This DTC sets when all of the following conditions are met: The cylinder head temperature at engine start exceeds the intake air temperature at engine start by greater than a calibrated value, typically 17deg.C (30deg.F). The cylinder head temperature exceeds a calibrated value, typically 107deg.C (225deg.F). The fuel system, heated oxygen and misfire monitors have not completed. The calibrated time to set this DTC has expired. Make sure the intake air temperature and the cylinder head temperature are similar when the engine is cold.Make sure the intake air temperature and the cylinder head temperature are similar when the engine is cold. Also make sure the CHT sensor and the actual engine operating temperatures are the same. Also make sure the CHT sensor and the actual engine operating temperatures are the same.
PCM P1022:00	Cylinder Head Temperature Sensor 2 Circuit Low: No Sub Type Information	Sets when the PCM detects a CHT circuit concern is present.
PCM P1023:00	Cylinder Head Temperature Sensor 2 Circuit High: No Sub Type Information	Sets when the PCM detects a Cylinder Head Temperature 2 (CHT2) circuit concern is present.
PCM P1024:00	Cylinder Head Temperature Sensor 2 Circuit Intermittent/Erratic: No Sub Type Information	Sets when the PCM detects a Cylinder Head Temperature 2 (CHT2) circuit concern is intermittently present while the engine is running.
PCM P1025:00	Cylinder Head Temperature Sensor 2 Out Of Self Test Range: No Sub Type Information	Sets when the PCM detects the CHT sensor is out of self-test range. The engine is not at a normal operating temperature.Bring the engine to operating temperature and repeat the self-test. If the engine overheats, check the cooling system. Refer to the appropriate DIAGNOSIS AND TESTING to diagnose the engine overheats symptom.
PCM P1026:00	Engine Coolant Temperature 1 / Cylinder Head Temperature 2 Correlation: No Sub Type Information	Sets when the PCM detects the ECT and Cylinder Head Temperature 2 (CHT2) sensor readings differ by greater than a calibrated value.Make sure the ECT and CHT 2 sensor readings are within 17 deg.C (30 deg.F) of each other after 6 hours at ambient temperature.
PCM P1285:00	Cylinder Head Overtemperature Condition: No Sub Type Information	Sets when the PCM detects an engine overheat condition was sensed by the CHT sensor.
PCM P1288:00	Cylinder Head Temperature Sensor Out Of Self Test Range: No Sub Type Information	Sets when the PCM detects the CHT sensor is out of self-test range. The engine is not at a normal operating temperature.Bring the engine to operating temperature. If cold, repeat the self-test. If the engine overheats, check the cooling system. Refer to the appropriate DIAGNOSIS AND TESTING The Engine Overheats for cooling system diagnosis.
PCM P1289:00	Cylinder Head Temperature Sensor Circuit High: No Sub Type Information	Sets when the PCM detects a CHT circuit open concern is present. The DTC P0118 may also set when this DTC sets.
PCM P128A:00	Cylinder Head Temperature Sensor Circuit Intermittent/Erratic: No Sub Type Information	Sets when the PCM detects the CHT circuit is intermittently open or short while the engine is running.
PCM P1290:00	Cylinder Head Temperature Sensor Circuit Low: No Sub Type Information	Sets when the PCM detects a CHT circuit short to ground concern is present. The DTC P0117 may also set when this DTC sets.

Possible Causes

ECT sensor circuitry concern
CHT sensor circuitry concern
Base engine concerns
Engine cooling system concerns
ECT sensor
CHT sensor (6G004)
PCM (12A650)

DL1 CHECK FOR DTCS

Are DTCs P0116, P0119, P0125, P0128, P017C, P017D, P017E, P1021, P1022, P1023, P1024, P1025, P1026, P1285, P1289, P128A, P1290, P2C39, P2C3A, P2C3B, or P2C3C present?

Yes	GO to DL2.

No	For temperature warning indicator lamp or gauge (applications with CHT sensor only) symptom: GO to DL13. For all others: REFER to the 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	For DTCs P0125, P0128, P101F, P1025, or P1288: GO to DL12. For all others: GO to DL3.

No	REFER to the DIAGNOSIS AND TESTING Engine Cooling to diagnose a cooling system concern.REPAIR as necessary.Clear the PCM DTCs. REPEAT the self-test.

DL3 CHECK THE RESISTANCE OF THE CHT (CYLINDER HEAD TEMPERATURE) SENSOR WITH THE ENGINE OFF

Ignition OFF.

For the CHT2 sensor,

Disconnect CHT2 Sensor connector.

Measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
CHT2 Pin 1, Component Side CHT2 Sensor Connector	Courtesy of FORD MOTOR COMPANY	SIGRTN Pin 2, Component Side CHT2 Sensor Connector

For all others,

Disconnect CHT Sensor connector.

Measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
CHT Pin 1, Component Side CHT Sensor Connector	Courtesy of FORD MOTOR COMPANY	SIGRTN Pin 2, Component Side CHT Sensor Connector

CYLINDER HEAD TEMPERATURE (CHT) AND CHT2 SENSOR EXPECTED VALUES

Temperature	CHT Sensor Values
deg.C	deg.F	Cold End (volts)	Hot End (volts)	Resistance (K ohms)
-40	-40	4.89	-	965.808
-30	-22	4.81	-	513.019
-20	-4	4.67	-	283.664
-10	14	4.45	-	162.584
0	32	4.14	-	96.255
10	50	3.73	-	59.175
20	68	3.26	-	37.387
30	86	2.74	-	24.215
40	104	2.23	-	16.043
50	122	1.76	-	10.85
60	140	1.36	-	7.487
70	158	1.04	-	5.268
80	176	0.79	3.99	3.775
85	185	0.69	3.86	3.215
90	194	0.60	3.71	2.75
95	203	0.53	3.56	2.361
100	212	0.46	3.41	2.034
110	230	-	3.07	1.523
120	248	-	2.74	1.155
130	266	-	2.41	0.8866
140	284	-	2.10	0.6891
150	302	-	1.81	0.5417
160	320	-	1.55	0.4301
170	338	-	1.33	0.3449
180	356	-	1.13	0.2791
190	374	-	0.96	0.2278
200	392	-	0.82	0.1875
210	410	-	0.70	0.155
220	428	-	0.60	0.130
230	446	-	0.51	0.109
240	464	-	0.44	0.092
250	482	0.35			0.078
260	500	0.33			0.067

Is the resistance within specification?

Yes	GO to DL4.

No	INSTALL a new Cylinder Head Temperature sensor. REFER to the CYLINDER HEAD TEMPERATURE (CHT) SENSOR Electronic Engine Controls. Clear the PCM DTCs. REPEAT the self-test.

DL4 CHECK FOR AN OPEN CIRCUIT

Ignition OFF.

Disconnect PCM connector.

For the CHT2 sensor,

Measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
1.5L EcoBoost (129kW/175PS) (CR), 1.5L EcoBoost (132kW/180PS) - I3 (Y1), 2.0L EcoBoost (184kW/250PS) - MI4, 2.0L EcoBoost (177kW/240PS) - MI4: CHT2 Pin E20PCM Connector 2.5L Duratec - Hybrid (121kW/164PS) (BG) 2.5L Duratec - Hybrid (FHEV 148kW/201PS, PHEV 165kW/225PS) (BG): CHT2PCM Connector	Courtesy of FORD MOTOR COMPANY	CHT2 Pin 1CHT2 Sensor Connector
2.5L Duratec - Hybrid (121kW/164PS) (BG) 2.5L Duratec - Hybrid (FHEV 148kW/201PS, PHEV 165kW/225PS) (BG): SIGRTN#CHT Pin EC1PCM Connector 1.5L EcoBoost (129kW/175PS) (CR), 1.5L EcoBoost (132kW/180PS) - I3 (Y1), 2.0L EcoBoost (184kW/250PS) - MI4, 2.0L EcoBoost (177kW/240PS) - MI4: SIGRTN#CHT Pin E19PCM Connector	Courtesy of FORD MOTOR COMPANY	SIGRTN Pin 2CHT2 Sensor Connector

For all others,

Measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
1.5L EcoBoost (129kW/175PS) (CR), 1.5L EcoBoost (132kW/180PS) - I3 (Y1), 2.0L EcoBoost (184kW/250PS) - MI4, 2.0L EcoBoost (177kW/240PS) - MI4: CHTPCM Connector 2.5L Duratec - Hybrid (121kW/164PS) (BG) 2.5L Duratec - Hybrid (FHEV 148kW/201PS, PHEV 165kW/225PS) (BG): CHT Pin EK3PCM Connector	Courtesy of FORD MOTOR COMPANY	CHT Pin 1CHT Sensor Connector
2.5L Duratec - Hybrid (121kW/164PS) (BG) 2.5L Duratec - Hybrid (FHEV 148kW/201PS, PHEV 165kW/225PS) (BG): SIGRTN#CHT Pin EC1PCM Connector 1.5L EcoBoost (129kW/175PS) (CR), 1.5L EcoBoost (132kW/180PS) - I3 (Y1), 2.0L EcoBoost (184kW/250PS) - MI4, 2.0L EcoBoost (177kW/240PS) - MI4: SIGRTN#CHT Pin E19PCM Connector	Courtesy of FORD MOTOR COMPANY	SIGRTN Pin 2CHT Sensor Connector

Is the resistance less than 5 Ohm??

Yes	GO to DL5.

No	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:

Positive Lead	Measurement / Action	Negative Lead
CHT2 Pin 1CHT2 Sensor Connector	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY

For all others,

Measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
CHT Pin 1CHT Sensor Connector	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY

Are the resistances greater than 10K ohms?

Yes	GO to DL6.

No	REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.

DL6 CHECK FOR A SHORT TO VOLTAGE

Ignition ON.

For the CHT2 sensor,

Measure the voltage between:

Positive Lead	Measurement / Action	Negative Lead
CHT2 Pin 1CHT2 Sensor Connector	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY

For all others,

Measure the voltage between:

Positive Lead	Measurement / Action	Negative Lead
CHT Pin 1CHT Sensor Connector	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY

Is any voltage present?

Yes	REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.

No	GO to DL7.

DL7 CHECK THE RESISTANCE OF THE CHT (CYLINDER HEAD TEMPERATURE) SENSOR

Ignition OFF.

Connect CHT Sensor connector.

Connect CHT2 Sensor connector.

Connect PCM connector.

Run the engine until the engine temperature stabilizes.

Ignition OFF.

For the CHT2 sensor,

Disconnect CHT2 Sensor connector.

Measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
CHT2 Pin 1, Component Side CHT2 Sensor Connector	Courtesy of FORD MOTOR COMPANY	SIGRTN Pin 2, Component Side CHT2 Sensor Connector

For all others,

Disconnect CHT Sensor connector.

Measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
CHT Pin 1, Component Side CHT Sensor Connector	Courtesy of FORD MOTOR COMPANY	SIGRTN Pin 2, Component Side CHT Sensor Connector

CYLINDER HEAD TEMPERATURE (CHT) AND CHT2 SENSOR EXPECTED VALUES

Temperature	CHT Sensor Values
deg.C	deg.F	Cold End (volts)	Hot End (volts)	Resistance (K ohms)
-40	-40	4.89	-	965.808
-30	-22	4.81	-	513.019
-20	-4	4.67	-	283.664
-10	14	4.45	-	162.584
0	32	4.14	-	96.255
10	50	3.73	-	59.175
20	68	3.26	-	37.387
30	86	2.74	-	24.215
40	104	2.23	-	16.043
50	122	1.76	-	10.85
60	140	1.36	-	7.487
70	158	1.04	-	5.268
80	176	0.79	3.99	3.775
85	185	0.69	3.86	3.215
90	194	0.60	3.71	2.75
95	203	0.53	3.56	2.361
100	212	0.46	3.41	2.034
110	230	-	3.07	1.523
120	248	-	2.74	1.155
130	266	-	2.41	0.8866
140	284	-	2.10	0.6891
150	302	-	1.81	0.5417
160	320	-	1.55	0.4301
170	338	-	1.33	0.3449
180	356	-	1.13	0.2791
190	374	-	0.96	0.2278
200	392	-	0.82	0.1875
210	410	-	0.70	0.155
220	428	-	0.60	0.130
230	446	-	0.51	0.109
240	464	-	0.44	0.092
250	482	0.35			0.078
260	500	0.33			0.067

Is the resistance within specification?

Yes	For the CHT2 sensor: GO to DL8. For all others: GO to DL10.

No	INSTALL a new Cylinder Head Temperature sensor. REFER to the CYLINDER HEAD TEMPERATURE (CHT) SENSOR Electronic Engine Controls. Clear the PCM DTCs. REPEAT the self-test.

DL8 CHECK THE CHT2 SENSOR

Ignition ON.

Measure the voltage between:

Positive Lead	Measurement / Action	Negative Lead
CHT2 Pin 1CHT2 Sensor Connector	Courtesy of FORD MOTOR COMPANY	SIGRTN Pin 2CHT2 Sensor Connector

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	REPAIR as necessary.Clear the PCM DTCs. REPEAT the self-test.

No	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.

Connect CHT2 Sensor connector.

Ignition ON.

Access the PCM and monitor the AAT (Temperature, Deg C) PID

Access the PCM and monitor the CHT (Temperature, Deg C) PID

Access the PCM and monitor the CHT2 (Temperature, Deg C) PID

Access the PCM and monitor the ECT (Temperature, Deg C) PID

Access the PCM and monitor the ECT1 (Temperature, Deg C) PID

Are the PID values within 16.67deg.C (30deg.F) of each other?

Yes	Unable to duplicate or identify the concern at this time.GO to Pinpoint Test Z .

No	For DTC P1285: GO to DL11. For all others: INSTALL a new Cylinder Head Temperature sensor. REFER to the CYLINDER HEAD TEMPERATURE (CHT) SENSOR Electronic Engine Controls.Clear the PCM DTCs. REPEAT the self-test.

DL10 INTERMITTENT CHECK

Ignition OFF.

Connect CHT Sensor connector.

Ignition ON.

Access the PCM and monitor the CHT (Temperature, Deg C) 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	REPAIR as necessary.Clear the PCM DTCs. REPEAT the self-test.

No	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 (CYLINDER HEAD TEMPERATURE) 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	REFER to the DIAGNOSIS AND TESTING Engine Cooling to diagnose the cooling system concern.Clear the PCM DTCs. REPEAT the self-test.

No	The system is operating correctly at this time. REPAIR any other DTC s 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 (Temperature, Deg C) PID

Record the PID value.

Is the PID temperature greater than 77 C (170.6 F)?

Yes	The system is operating correctly at this time.Clear the PCM DTCs. REPEAT the self-test.

No	REFER to the DIAGNOSIS AND TESTING Engine Cooling, 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 DTC (DIAGNOSTIC TROUBLE CODE) S

NOTE: For Engine Temperature Warning Indicator system concerns, refer to the DIAGNOSIS AND TESTING .

Disconnect PCM connector.

Ignition ON.

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	GO to DL14.

No	REFER to the DIAGNOSIS AND TESTING 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	REFER to the DIAGNOSIS AND TESTING Engine Cooling, to diagnose the engine overheating symptom. REPAIR as necessary.Clear the PCM DTCs. REPEAT the self-test.

No	REFER to the DIAGNOSIS AND TESTING Engine Cooling to diagnose the loss of coolant. REPAIR as necessary.Clear the PCM DTCs. REPEAT the self-test.