P0049

P0049-TURBOCHARGER TURBINE OVERSPEED

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The Turbocharger Speed Sensor is a variable reluctance speed sensor. It consists of a coil of wire and an iron core. The target on the turbocharger shaft is a ground flat surface in the center of the shaft. As the flat surface on the turbocharger shaft spins past the speed sensor, a signal is generated. The Powertrain Control Module (PCM) interprets this signal and converts it to a turbocharger speed reading. If this fault becomes active the PCM will light the MIL light immediately. During this time the PCM uses an estimated turbocharger speed. An engine power derate may be experienced. The PCM turns off the MIL when the diagnostic runs and passes in four consecutive drive cycles.

- When Monitored:
When the key is on and the Powertrain Control Module (PCM) detects a valid turbocharger speed.

- Set Condition:
Powertrain Control Module (PCM) detects that the Turbocharger Speed Sensor is out of range high.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. OTHER DTCs
1. With the scan tool, read DTCs.

Are any DTCs present for Inlet Air Pressure Sensor or Boost Pressure Sensor?

Yes

- Troubleshoot other DTCs first.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 2

2. INTERMITTENT CONDITION
1. Start the engine.
2. Using the accelerator pedal, accelerate the engine speed to high idle and hold the engine speed at high idle for at least 20 seconds.

Does DTC P0049 become active?

Yes

- Go To 3

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test

3. TURBOCHARGER SPEED SENSOR




1. Turn Ignition off.
2. Disconnect the Turbocharger Speed Sensor connector.

NOTE: Check connectors - Clean/repair as necessary.

3. Measure the resistance across the (K540) Turbocharger Speed Sensor Signal circuit and the (K541) Turbocharger Speed Sensor Return circuit at the Turbocharger Speed Sensor.

Is the resistance between 600 and 1600 Ohms?

Yes

- Go To 4

No

- Replace the Turbocharger Speed Sensor.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

4. CHECK THE (K540) TURBO SPEED SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND




1. Measure the resistance between ground and the (K540) Turbocharger Speed Sensor Signal circuit at the Turbocharger Speed Sensor connector.

Is the resistance greater than 10k Ohms?

Yes

- Go To 5

No

- Repair the (K540) Turbocharger Speed Sensor Signal circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

5. CHECK THE (K540) TURBO SPEED SENSOR SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE




1. Disconnect the PCM C1 harness connector.

NOTE: Check connectors - Clean/repair as necessary.

2. Measure the resistance of the (K540) Turbocharger Speed Sensor Signal circuit between the Turbocharger Speed Sensor harness connector and the PCM C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 6

No

- Repair the (K540) Turbocharger Speed Sensor Signal circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

6. CHECK THE (K541) TURBO SPEED SENSOR RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE




1. Measure the resistance of the (K541) Turbocharger Speed Sensor Return circuit between the Turbocharger Speed Sensor harness connector and the PCM C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 7

No

- Repair the (K541) Turbocharger Speed Sensor Return circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

7. POWERTRAIN CONTROL MODULE
1. Reconnect PCM C1 harness connector.
2. Reconnect the Turbocharger Speed Sensor connector.
3. Turn the ignition on.
4. With the scan tool, clear DTCs.
5. Test drive the vehicle.

Does DTC P0049 become active?

Yes

- Replace the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Repair complete.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.