Engine Coolant Temperature Sensor

2002 PCED OBDII-Diesel

SECTION 5: Pinpoint Tests

DM: Engine Coolant Temperature (ECT) Sensor — Manual Transmission Only

DM: Introduction

DM1 KOEO DIAGNOSTIC TROUBLE CODE P0117

DTC P0117 indicates ECT circuit out of range low.
Possible causes:
ECT signal circuit ground short
failed/poor connection
failed ECT sensor
failed PCM

Disconnect ECT harness connector.
Inspect for damaged, pushed out or corroded pins.
Check for opposite failure with ECT disconnected.
Perform KOEO On-Demand Self Test.

Is DTC P0118 present?

Yes

INSTALL a new ECT sensor. RESTORE vehicle. CLEAR DTCs and RETEST.

GO to DM2 .

DM2 CHECK ECT SIGNAL CIRCUIT FOR SHORT TO GND

Install breakout box, leave PCM disconnected.
Measure resistance between pin 2 on the ECT harness connector and ground.

Is the resistance greater than 10,000 ohms?

Yes

INSTALL a new PCM. RESTORE vehicle. CLEAR DTCs and RETEST.

REPAIR short to ground in ECT signal circuit. RESTORE vehicle. CLEAR DTCs and RETEST. INSTALL a new PCM.

DM3 KOEO DIAGNOSTIC TROUBLE CODE P0118

DTC P0118 indicates ECT circuit out of range high.
Possible causes:
open or PWR short in ECT signal circuit
open in signal return circuit
failed ECT sensor
failed/poor connection
failed PCM

Disconnect ECT harness connector.
Key on, engine off.
Measure resistance between pin 1 on the ECT harness connector and ground.

Is the resistance less than 5 ohms?

Yes

GO to DM4 .

REPAIR open in signal return circuit to ECT sensor. RESTORE vehicle. CLEAR DTCs and RETEST.

DM4 INDUCE OPPOSITE FAILURE

Key on, engine off.
Jumper pins 1 and 2 on the ECT harness connector.
Perform KOEO On-Demand Self Test.

Is DTC P0117 present?

Yes

INSTALL a new ECT sensor. RESTORE vehicle. CLEAR DTCs and RETEST.

GO to DM5 .

DM5 CHECK ECT SIGNAL CIRCUIT FOR SHORT TO POWER

Install breakout box; leave PCM disconnected.
ECT harness connector disconnected, jumper removed.
Measure resistance between PCM test pin 37 and pins 55, 71, 91 and 97.

Is each resistance greater than 10,000 ohms?

Yes

INSTALL a new PCM. RESTORE vehicle. CLEAR DTCs and RETEST.

REPAIR short to PWR or VREF in ECT signal circuit. RESTORE vehicle. CLEAR DTCs and RETEST.

DM6 CHECK SIGNAL RETURN

Key off.
Measure resistance at signal return circuit 359 (GY/RD) between ECT harness connector and ground.

Is the resistance less than 5 ohms?

Yes

GO to DM7 .

REPAIR open in signal return circuit 359 (GY/RD). RESTORE vehicle. CLEAR DTCs and RETEST.

DM7 ECT SIGNAL CONTINUITY CHECK

Install breakout box; leave PCM disconnected.
ECT harness connector disconnected, jumper removed.
Measure resistance between PCM test pin 37 and 923 (OG/BK) at the ECT harness connector.

Is the resistance less than 5 ohms?

Yes

GO to DM8 .

REPAIR open ECT signal circuit 923 (OG/BK). RESTORE vehicle. CLEAR DTCs and RETEST.

DM8 CONTINUOUS MEMORY CODE P0117

DTC P0117 indicates that an ECT circuit out of range low was detected. The DTC was set under normal driving conditions.
Possible causes:
ECT signal circuit ground short
failed/poor connection
failed ECT sensor
failed PCM

Perform KOEO On-Demand Self Test.

Is DTC P0117 present?

Yes

GO to DM1 .

GO to DM9 .

DM9 INTERMITTENT CIRCUIT FAILURE CHECK — DTC P0117

Clear continuous DTCs.
Key on, engine off.
Shake and wiggle the electrical harness working from the ECT sensor to the PCM connector.
Re-check continuous DTCs.

Is P0117 present?

Yes

REPAIR intermittent circuit failure. RESTORE vehicle. CLEAR DTCs and retest.

GO to DM10 .

DM10 INTERMITTENT ECT SENSOR CHECK

Key on, engine off.
Lightly tap the ECT sensor to simulate road shock.
Check continuous DTCs.

Is DTC P0117 present?

Yes

INSTALL a new ECT sensor. VISUALLY inspect ECT harness connector for damaged pins. RESTORE vehicle. CLEAR DTCs and RETEST.

Unable to duplicate or identify concern at this time. RESTORE vehicle. CLEAR DTCs.

DM11 CONTINUOUS MEMORY CODE P0118

DTC P0118 indicates that an ECT circuit out of range high was detected. The DTC was set during normal driving conditions.
open or PWR short in ECT signal circuit
open in signal return circuit
failed ECT sensor
failed/poor connection
failed PCM

Perform KOEO On-Demand Self Test.

Is DTC P0118 present?

Yes

GO to DM3 .

GO to DM12 .

DM12 INTERMITTENT CIRCUIT FAILURE CHECK — DTC P0118

Clear continuous DTCs.
Key on, engine off.
Shake and wiggle the electrical harness working from the ECT sensor to the PCM connector.
Re-check continuous DTCs.

Is DTC P0118 present?

Yes

REPAIR intermittent circuit failure. RESTORE vehicle. CLEAR DTCs and RETEST.

GO to DM13 .

DM13 INTERMITTENT ECT SENSOR CHECK

Key on, engine off.
Lightly tap on the ECT sensor to simulate road shock.
Check continuous DTCs.

Is DTC P0118 present?

Yes

INSTALL a new ECT sensor. Visually INSPECT ECT harness connector for damaged pins. RESTORE vehicle. CLEAR DTCs and RETEST.

Unable to duplicate or identify concern at this time. RESTORE vehicle. CLEAR DTCs.

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