Diagnostic Instructions
| • | 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. |
DTC Descriptors
DTC P0117: Engine Coolant Temperature (ECT) Sensor Circuit Low VoltageDTC P0118: Engine Coolant Temperature (ECT) Sensor Circuit High Voltage
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
ECT Sensor Signal | P0117 | P0118 | P0118 | P0116, P0128 |
Low Reference | -- | P0118 | P0118 | P0128 |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine Running Parameter Normal Range: -39 to +120°C (-38 to +248°F) | |||
ECT Sensor Signal | 149°C (300°F) | -40°C (-40°F) | -40°C (-40°F) |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F) |
Circuit/System Description
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 a ground for the ECT low reference circuit.
Conditions for Running the DTC
P0117
| • | The ignition is ON. |
| • | DTC P0117 runs continuously within the enabling condition. |
P0118
| • | The ignition is ON. |
| • | DTC P0118 runs continuously within the enabling condition. |
Conditions for Setting the DTC
P0117
The ECM detects that the ECT Sensor is warmer than 149°C (300°F) for more than 10 seconds.
P0118
The ECT sensor temperature is colder than -39°C (-38°F) for more than 60 seconds.
Action Taken When the DTC Sets
DTCs P0117 and P0118 are Type A DTCs.
Conditions for Clearing the DTC
DTCs P0117 and P0118 are Type A DTCs.
Diagnostic Aids
An ECT sensor signal circuit or low reference circuit that is shorted to another 5-volt reference circuit can cause a DTC P0118 to set.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, observe the ECT Sensor parameter. The reading should be between -37 to +139°C (-35 to +282°F), depending on the current ambient temperature and the vehicle operating conditions.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the ECT sensor.
- Ignition OFF and scan tool disconnected for 90 seconds, test for less than 5 ohms between the low reference circuit terminal B and ground.
- Ignition ON, verify the scan tool ECT sensor parameter is colder than -39°C (-40°F).
- Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool ECT Sensor parameter is warmer than 148°C (300°F)
- If all circuits test normal, test or replace the ECT sensor.
| ⇒ | 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 terminal A 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. |
Component Testing
Measure and record the resistance of the ECT sensor at various ambient temperatures and compare those measurements to the Temperature vs. Resistance Table. Refer to Temperature Versus Resistance.
Repair Instructions
| • | Control Module References for ECM replacement, setup, and programming |
Repair Verification
- Install any components or connectors that have been removed or replaced during diagnosis.
- Perform any adjustment, programming, or setup procedures that are required when a component or module is removed or replaced.
- Clear the DTCs.
- Turn OFF the ignition for 90 seconds.
- Duplicate the Conditions for Running the DTC and use the Freeze Frame/Failure Records, if applicable, in order to verify the DTC does not reset. If the DTC resets or another DTC is present, refer to Diagnostic Trouble Code (DTC) List - Vehicle and perform the appropriate diagnostic procedure.
- Engine running, observe the scan tool Soot Mass parameter.
| ⇒ | If the Soot Mass value is less than 30 grams, perform the Diesel Particulate Filter (DPF) Regeneration Enable |
| ⇒ | If the Soot Mass value is greater than 30 grams, perform the Diesel Particulate Filter (DPF) Service Regeneration |
