P0116–ENGINE COOLANT TEMPERATURE SENSOR CIRCUIT PERFORMANCE

For a complete wiring diagram Refer to Section 8W.

Theory of Operation

Engine Coolant Temperature Sensor performance looks at the outputs of three temperature sensors and compares them under cold start conditions. Following a start to run delay time, the outputs of the ambient, engine coolant, and intake air temperature sensors will be compared. If the intake air and ambient air temperature sensors agree and the engine coolant temperature does not agree, the engine coolant temperature sensor is declared as irrational.

When Monitored:
Engine off time is greater than 480 minutes. Ambient temperature is greater than 4°C (38°F).
Set Condition:
After a calibrated amount of cool down time the PCM compares the ECT Sensor, IAT Sensor, and the Ambient Air Temp Sensor values. If the IAT Sensor value is not within 10 °C (50° F) of the other two temperature sensors. Two Trip Fault. Three good trips to turn off the MIL.

Possible Causes

EXCESSIVE RESISTANCE IN THE (K2) ECT SIGNAL CIRCUIT

EXCESSIVE RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT

ECT SENSOR

PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Diagnostic Test

1.ACTIVE DTC

NOTE: It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.

Is the DTC Active or Pending at this time?

Yes

Go To 2

Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

2.ECT SENSOR VOLTAGE ABOVE 4.6 VOLTS

Is the voltage above 4.6 volts?

Yes

Go To 3

Go To 4

3.ECT SENSOR

Is the voltage below 1.0 volt with the jumper wire installed?

Yes

Replace the ECT Sensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Go To 4
NOTE: Remove the jumper wire before continuing.

4.EXCESSIVE RESISTANCE IN THE (K2) ECT SIGNAL CIRCUIT

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 and #8815-1 to perform diagnosis.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

Is the voltage below 0.5 of a volt?

Yes

Go To 5

Repair the open in the (K2) ECT Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

5.EXCESSIVE RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT

Is the voltage below 0.5 of a volt?

Yes

Go To 6

Repair the open in the (K900) Sensor ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

6.PCM

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

Were there any problems found?

Yes

Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)