• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
ECT Sensor Signal | P0117 | P0116, P0118, P0119 | P0118*, P0119* | P0116* |
Low Reference | -- | P0116, P0118, P0119 | P0118*, P0119* | P0116* |
* Internal ECM or sensor damage may occur if the circuit is shorted to B+ |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Engine operating in Closed Loop Parameter Normal Range: -39 to +142°C (-38 to +288°F) Varies with coolant temperature. | |||
ECT Sensor Signal | 143°C (289°F) | -40°C (-40°F) | -40°C (-40°F)* |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F)* |
* Internal ECM or ECT sensor damage may occur if the circuit is shorted to B+ |
The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT signal circuit and supplies a ground to the low reference circuit. The ECM monitors the performance of the ECT sensor. If the ECM detects excessive noise or rapid fluctuations in the ECT signal, this DTC sets.
The following table illustrates the difference between temperature, resistance, and voltage:
ECT | ECT Resistance | ECT Signal Voltage |
---|---|---|
Cold | High | High |
Warm | Low | Low |
• | DTC P0117, P0118, P0125, or P0128 is not set. |
• | The ignition is ON or the engine is operating. |
• | DTC P0119 runs continuously once the above conditions are met. |
• | The ECM detects that the ECT changed +/-5°C (+/-9°F) greater than the expected value during a calibrated amount of time. |
• | The condition exists for approximately 1 minute. |
DTC P0119 is a Type B DTC.
DTC P0119 is a Type B DTC.
• | Test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a DTC or a driveability condition. Refer to Temperature Versus Resistance - Engine Coolant Temperature Sensor . |
• | If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F). |
• | After starting a cold engine, the ECT sensor temperature should rise steadily, then stabilize after the thermostat opens. |
• | High resistance on either the ECT sensor signal circuit or the ECT sensor low reference circuit could set a DTC. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
⇒ | Repair the suspected harness or connection if the ECT parameter fluctuates greater than 3°C (5°F) while moving the related harnesses and connectors. |
⇒ | If you suspect a condition with engine cooling system, refer to Symptoms - Engine Cooling . |
⇒ | If greater than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM. |
Notice: Do NOT use a test lamp to test the continuity of the circuit. Damage to the control module may occur due to excessive current draw.
Important: The control module or the sensor may be damaged if the circuit is shorted to B+.
⇒ | If greater than the specified value, test the low reference circuit for a short to B+. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
Important: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.
⇒ | If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
Important: A thermometer can be used to test the sensor off the vehicle.
⇒ | If not within the specified range, replace the ECT sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for engine control module replacement, setup, and programming |