P0115
DTC P0115, P0117, or P0118
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0115
- Engine Coolant Temperature (ECT) Sensor Circuit
DTC P0117
- Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage
DTC P0118
- Engine Coolant Temperature (ECT) Sensor Circuit High Voltage
Diagnostic Fault Information
Typical Scan Tool Data
Circuit Description
The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The powertrain control module (PCM) 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:
Conditions for Running the DTC
P0115, P0117, or P0118
* The ignition is ON or the engine is operating.
* The DTC runs continuously once the above condition is met.
Conditions for Setting the DTC
P0115
* The temperature input is -40°C (-40°F), 4.91 volts, for at least 0.5 seconds.
OR
* The temperature input is 140°C (284°F), 0.18 volts, for at least 0.5 seconds.
P0117
The temperature input is more than 140°C (284°F), 0.14 volts, for at least 0.5 seconds.
P0118
The temperature input is less than -40°C (-40°F), 4.91 volts, for at least 0.5 seconds.
Action Taken When the DTC Sets
DTC P0115, P0117 and P0118 are Type A DTCs.
Conditions for Clearing the MIL/DTC
DTC P0115, P0117 and P0118 are Type A DTCs.
Diagnostic Aids
* 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 in the circuit of the ECT sensor could set a DTC.
Reference Information
Schematic Reference
Engine Controls Schematics (Electrical Diagrams)
Connector End View Reference
* Powertrain Control Module Connector End Views (Powertrain Control Module Connector End Views)
* Engine Controls Connector End Views (Engine Controls Connector End Views)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Engine idling for 1 minute. Observe the DTC information with a scan tool. DTCs P0115, P0117 and P0118 should not set.
2. 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.
Circuit/System Testing
1. Ignition OFF, disconnect the ECT sensor.
2. Test for less than 5 ohms between the low reference circuit terminal 1 and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit tests normal, replace the PCM.
3. Ignition ON, verify that the ECT sensor parameter is at -40°C (-40°F).
• If greater than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the PCM.
4. Install a 3A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1. Verify the ECT sensor parameter is greater than 139°C (280°F).
• 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 PCM.
5. If all circuits test normal, test or replace the ECT sensor.
Component Testing
1. Ignition OFF, disconnect the harness connector at the engine coolant temperature (ECT) sensor.
Important: A thermometer can be used to test the sensor off the vehicle.
2. Test the ECT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature Versus Resistance (Temperature Versus Resistance) table and verify that the resistance is within 5 percent of the specification.
• If not within the specified range, replace the ECT sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Engine Coolant Temperature Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for engine control module replacement, setup, and programming