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 P1114: Engine Coolant Temperature (ECT) Sensor Circuit Intermittent Low VoltageDTC P1115: Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
ECT Sensor Signal | P0117, P1114 | P0118, P1115 | P0118, P1115* | P0115 |
Low Reference | -- | P0118, P1115 | -- | P0115 |
* Internal ECM damage may occur if the circuit is shorted to B+. | ||||
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine operating in Closed Loop. Parameter Normal Range: Varies with ambient temperature. | |||
ECT Sensor Signal | 129°C (264°F), 0.0 Volts | -40°C (-40°F), 5.0 Volts | -40°C (-40°F), 5.0 Volts¹ |
Low Reference | -- | -40°C (-40°F), 5.0 Volts | -- |
¹ Internal ECM damage may occur if the circuit is shorted to B+. | |||
Circuit 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 supplies a ground to the low reference circuit.
The following table illustrates the difference between temperature, resistance, and voltage:
ECT | ECT Resistance | ECT Signal Voltage |
|---|---|---|
Cold | High | High |
Warm | Low | Low |
Conditions for Running the DTC
| • | The engine has been running for greater than 2 minutes. |
| • | The DTCs run continuously when the above condition is met. |
Conditions for Setting the DTC
P1114
The ECM detects that the ECT sensor is greater than 149°C (300°F ) intermittently.
P1115
The ECM detects that the ECT sensor is less than -38°C (-34°F) intermittently.
Action Taken When the DTC Sets
DTCs P1114 and P1115 are Type C DTCs.
Conditions for Clearing the MIL/DTC
DTCs P1114 and P1115 are Type C DTCs.
Reference Information
Schematic 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
- Engine running, observe the DTC Information with a scan tool. DTCs P0117 or P0118, is not set.
- Observe the DTC Information with a scan tool. DTC P1114 or P1115 should not set.
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
| ⇒ | If any DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle . |
Circuit/System Testing
Engine running, observe the scan tool engine coolant temperature (ECT) sensor parameter while moving the related wiring harness and harness connectors. The reading should not change abruptly.
| ⇒ | If the reading changes abruptly, repair the wiring harness and harness connectors. |
Component Testing
- Ignition OFF, disconnect the harness connector at the engine coolant temperature (ECT) sensor.
- Test the ECT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature Versus Resistance table and verify that the resistance is within 5 percent of the specification.
Important: A thermometer can be used to the used to test the sensor off the vehicle.
| ⇒ | If not within the specified range, replace the ECT sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for engine control module replacement, setup, and programming |
