P0115-ENGINE COOLANT TEMP SENSOR SIGNAL VOLTAGE TOO LOW
For a complete wiring diagram Refer to Section 8W
- When Monitored:
With the ignition on.
- Set Condition:
The Engine Coolant Temperature Sensor signal is below 0.12 volt.
| Possible Causes |
| ECT SENSOR |
| ECT SENSOR SIGNAL CIRCUIT SHORTED TO GROUND |
| ECT SENSOR SIGNAL AND GROUND CIRCUITS SHORTED TOGETHER |
| ENGINE CONTROL MODULE |
Diagnostic Test
1. CHECK FOR ACTIVE DTCNOTE: If the ECM detects and stores a DTC, the ECM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed on the scan tool at the same time the DTC is displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the scan tool, monitor the Engine Coolant Temperature (ECT) Sensor voltage.
Is the ECT Sensor voltage below 0.25 volt?
Yes
- Go To2
No
- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
2. ECT SENSOR
Turn the ignition off.
Disconnect the ECT Sensor harness connector.
Turn the ignition on.
With the scan tool, read the ECT Sensor voltage.
Is the voltage above 4.0 volts?
Yes
- Replace the ECT Sensor in accordance with the Service Information.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
No
- Go To3
3. ECT SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the ECT Sensor Signal circuit.
Is the resistance above 1000 ohms?
Yes
- Go To4
No
- Repair the ECT Sensor Signal circuit for a short to ground.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
4. ECT SENSOR SIGNAL AND GROUND CIRCUITS SHORTED TOGETHER
Measure the resistance between the ECT Sensor Signal circuit and Sensor Ground circuit.
Is the resistance above 1000 ohms?
Yes
- Go To5
No
- Repair the ECT Sensor Signal and Ground circuits for a short together.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
5. ENGINE CONTROL MODULE
If there are no possible causes remaining, view repair.
Repair
- Replace and program the Engine Control Module in accordance with the Service Information.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).