Pinpoint Test DL: Cylinder Head Temperature (CHT) Sensor
WARNING: This page is about a different variant/trim than selected.
NOTE:
On a typical vehicle, the CHT sensor is located in the cylinder head and the CHT2 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 chart 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 17°C (30°F). The engine coolant temperature exceeds a calibrated value, typically 107°C (225°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 P0125:00 | Insufficient Coolant Temp For Closed Loop Fuel Control: No Sub Type Information | Sets when the PCM detects the ECT or the CHT sensor has not achieved the required temperature level to enter closed loop operating conditions within a specified amount of time after starting the engine. Compare the thermostat specification to the actual engine coolant temperature using the engine temperature PID (ECT or CHT. The temperature reading should be similar when the engine is at a normal operating temperature. |
| PCM P0128:00 | Coolant Thermostat (Coolant Temp Below Thermostat Regulating Temperature): No Sub Type Information | Sets when the PCM detects the thermostat monitor has not achieved the required engine operating temperature within a specified amount of time. Refer to the Thermostat Monitor description for additional information. |
| 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 17°C (30°F). The cylinder head temperature exceeds a calibrated value, typically 107°C (225°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 Cylinder Head Temperature 2 (CHT2) 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 2 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 Engine Cooling 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°C (30°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 Engine Cooling 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 Sources
- ECT sensor circuitry concern
- CHT sensor circuitry concern
- Base engine concerns
- Engine cooling system concerns
- ECT sensor
- CHT sensor (6G004)
- PCM (12A650)