• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provide an overview of each diagnostic category. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
ECT Sensor Signal | P0117 | P0118 | P0118 | P0118 | P0116, P0125, P0128 |
Low Reference | -- | P0118 | P0118 | P0118 | P0125, P0128 |
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
---|---|---|---|---|
ECT Sensor Signal | -39 to +120°C (-38 to +248°F) | 150°C (302°F) | -40°C (-40°F) | -40°C (-40°F) |
Low Reference | -- | -- | -40°C (-40°F) | -40°C (-40°F) |
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 engine is running for more than 10 seconds. |
OR |
• | The ignition is ON when the intake air temperature (IAT) is less than 50°C (122°F). |
• | This DTC runs continuously within the enabling conditions. |
• | The engine is running for more than 10 seconds. |
OR |
• | The ignition is ON when the IAT is more than 0°C (32°F). |
• | This DTC runs continuously within the enabling conditions. |
The ECM detects that the ECT is more than 149°C (300°F) for more than 5 seconds.
The ECM detects that the ECT is less than -39°C (-38°F) for more than 5 seconds.
DTCs P0117 and P0118 are Type B DTCs.
DTCs P0117 and P0118 are Type B DTCs.
Engine Controls Connector End Views
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Caution: Under pressure, the temperature of the solution in the radiator can be considerably higher, without boiling. Removing the radiator cap while the engine is hot (pressure is high), will cause the solution to boil instantaneously, with explosive force. The solution will spew out over the engine, fenders, and the person removing the cap. Serious bodily injury may result. Flammable antifreeze, such as alcohol, is not recommended for use at any time. Flammable antifreeze could cause a serious fire.
Important: All electrical components and accessories must be turned OFF and allowed to power down.
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM. |
⇒ | If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
Measure and record the resistance of the ECT sensor at various ambient temperatures, then compare those measurements to the Temperature vs Resistance table. Refer to Temperature Versus Resistance .
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |