P0117

SYMPTOM
P0117-ENGINE COOLANT TEMPERATURE SENSOR CIRCUIT LOW

WHEN MONITORED
With the ignition on. Battery voltage greater than 10.4 volts.

SET CONDITION
The Engine Coolant Temperature (ECT) sensor circuit voltage at the PCM is less than 0.078 of a volt for more than 2.8 seconds. One Trip Fault. Three good trips to clear the MIL.

POSSIBLE CAUSES
- (K2) ECT SIGNAL CIRCUIT SHORTED TO GROUND
- (K2) ECT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
- ECT SENSOR
- PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Scan Tool Testing and Procedures

DIAGNOSTIC TEST
1. ECT SENSOR VOLTAGE BELOW 0.078 OF A VOLT





Ignition on, engine not running. With a scan tool, read the ECT voltage.
Is the voltage below 0.078 of a volt?
Yes>> Go To 2
No>> Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5. Powertrain Verification Test - Ver 5

2. ECT SENSOR





Turn the ignition off.
Disconnect the ECT harness connector.
Ignition on, engine not running.
With a scan tool, read ECT voltage.
Is the voltage above 1.0 volt?
Yes>> Replace the ECT Sensor. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
No>> Go To 3

3. (K2) ECT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT





Turn the ignition off.
Disconnect the PCM harness connectors.
Measure the resistance between the (K900) Sensor ground circuit and the (K2) ECT Signal circuit in the ECT Sensor harness connector.
Is the resistance below 5.0 ohms?
Yes>> Repair the short to between the (K900) Sensor ground circuit and the (K2) ECT Signal circuit. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
No>> Go To 4

4. (K2) ECT SIGNAL CIRCUIT SHORTED GROUND





Measure the resistance between ground and the (K2) ECT Signal circuit in the ECT Sensor harness connector.
Is the resistance below 100 ohms?
Yes>> Repair the short to ground in the (K2) ECT Signal circuit. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
No>> Go To 5

5. PCM

Note: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Were there any problems found?
Yes>> Repair as necessary. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.
No>> Replace and program the Powertrain Control Module per Service Information. Perform (NGC) POWERTRAIN VERIFICATION TEST VER-5.