2000 - 2999: 2649

2649-TEMPERATURE SENSOR UPSTREAM OF DIESEL PARTICULATE FILTER - PLAUSIBILITY ERROR

- When Monitored:
With the engine running.

- Set Condition:
The Engine Control Module (ECM) detects an implausible signal from the temperature sensor upstream of the Diesel Particulate Filter (Pre-Diesel Particulate Filter).





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview

1. DTC IS ACTIVE
1. Turn the ignition on, engine not running.
2. With the scan tool, clear DTCs in the Engine Control Module (ECM).
3. Start the engine and monitor the scan tool for at least two minutes.
4. Perform several engine run cycles, turning the ignition off for at least 20 seconds between each engine run cycle.
5. With the scan tool, select View DTCs.
Is the status Active for this DTC?

Yes

- Go To 2

No

- Perform the INTERMITTENT DTC Diagnostic Procedure. Initial Inspection and Diagnostic Overview

2. PRE DIESEL-PARTICULATE FILTER TEMPERATURE SENSOR SIGNAL CIRCUIT OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the Pre-Diesel Particulate Filter Temperature Sensor harness connector.
3. Disconnect the Engine Control Module harness connector.
4. Measure the resistance of the Pre-Diesel Particulate Filter Temperature Sensor Signal circuit between the Catalytic Converter Temperature Sensor harness connector and the Engine Control Module harness connector.
Is the resistance below 5.0 Ohms?

Yes

- Go To 3

No

- Repair the open or high resistance in the Pre-Diesel Particulate Filter Temperature Sensor Signal circuit.
- Perform the ECM Verification Test. Verification Tests

3. PRE-DIESEL PARTICULATE FILTER TEMPERATURE SENSOR GROUND CIRCUIT OPEN/HIGH RESISTANCE
1. Measure the resistance of the Pre-Diesel Particulate Filter Temperature Sensor Ground circuit between the Catalytic Converter Temperature Sensor harness connector and the Engine Control Module harness connector.
Is the resistance below 5.0 Ohms?

Yes

- Go To 4

No

- Repair the open or high resistance in the Pre-Diesel Particulate Filter Temperature Sensor Ground circuit.
- Perform the ECM Verification Test. Verification Tests

4. PRE-DIESEL PARTICULATE FILTER TEMPERATURE SENSOR





1. Using the table as a guide, measure the resistance of the Pre-Diesel Particulate Filter Temperature Sensor.
Is the resitance reading within specifications?

Yes

- Replace the Engine Control Module.
- Perform the ECM Verification Test. Verification Tests

No

- Replace the Pre-Diesel Particulate Filter Temperature Sensor.
- Perform the ECM Verification Test. Verification Tests