P2580

P2580-TURBOCHARGER SPEED SENSOR CIRCUIT LOW





For a complete wiring diagram Refer to Diagrams/Electrical.

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 in the center of the shaft. As the flat on the turbocharger shaft spins past the speed sensor, a signal is generated. The ECM interprets this signal and converts it to a turbocharger speed reading. If this fault becomes active the ECM will light the MIL light immediately. During this time the ECM uses an estimated turbocharger speed. An engine power derate may be experienced. The ECM turns off the MIL when the diagnostic runs and passes in 4 consecutive drive cycles.

- When Monitored:
When the key is on and the ECM detects a valid turbocharger speed.

- Set Condition:
ECM detects turbocharger speed detected is less than a calibration limit for a calibratable amount of time.







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


Diagnostic Test


1. OTHER DTCS
With the scan tool, read DTCs.
Are any DTCs present for inlet air pressure or boost pressure?

Yes


- Troubleshoot other DTCs first


No


- Go To 2
-



2. INTERMITTENT CONDITION
Use the accelerator pedal to accelerate the engine speed to a high idle (100%) and hold the engine speed at high idle for at least 20 seconds
Does P-2580 come active?

Yes


- Go To 3


No


- Refer to the INTERMITTENT CONDITION - DIESEL Diagnostic Procedure. Intermittent Condition



3. TURBOCHARGER SPEED SENSOR




Turn Ignition off.
Disconnect the Turbocharger Speed Sensor harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance of the Turbo Speed Sensor by probing (K540) Turbo Speed Signal circuit and the (K541) Turbo Speed Sensor ground 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 POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test .



4. (K541) TURBO SPEED SENSOR GROUND CIRCUIT SHORTED TO GROUND




Disconnect the ECM C1 harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance between ground and the (K541) Turbo Speed Sensor ground circuit in the sensor harness connector.
Is the resistance greater than 100k ohms?

Yes


- Go To 5


No


- Repair the short to ground in the (K541) Turbo Speed Sensor ground circuit.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test .



5. TURBO SPEED SENSOR CIRCUIT CHECK




Reconnect the turbocharger speed sensor harness connector.
Measure the resistance between the (K540) Turbo Speed Signal circuit and (K541) Turbo Speed Sensor ground circuit at the ECM harness connector.

NOTE: The resistance of the turbocharger speed sensor circuit must not be more than 10 ohms greater than the resistance of the turbocharger speed sensor. The turbocharger speed sensor resistance was read in step 2.

Is the resistance within 10 ohms of sensor resistance?

Yes


- Go To 6


No


- There is high resistance or an open circuit in the engine harness. Otherwise there is a low resistance (short) across the sensor circuits. Repair/replace engine harness.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test .



6. (K540) SPEED SENSOR SIGNAL SHORTED TO GROUND




Measure the resistance between ground and the (K540) Turbo Speed Signal circuit at the ECM harness connector.
Is the resistance greater than 100k ohms?

Yes


- Go To 7


No


- There is a short to ground in the (K540) Turbo Speed Signal circuit.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test .



7. (K540) TURBO SPEED SIGNAL CIRCUIT SHORTED TO OTHER CIRCUITS




Measure the resistance between the (K540) Turbo Speed Signal circuit all other circuits in the ECM harness connector except the turbocharger speed (K541) Turbo Speed Sensor ground circuit.
Is the resistance greater than 100k ohms?


Yes


- Go To 8


No


- There is a short between circuits of the ECM harness. Repair or replace the engine harness.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test .



8. ECM
Reconnect the ECM harness connector.
Start the engine.
Use the accelerator pedal to accelerate the engine speed to a high idle (100%) and hold the engine speed at high idle for at least 20 seconds
Does DTC P2580 come active during engine operation?

Yes


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


No


- The problem may exist in the turbocharger speed sensor circuit or it may exist with other vehicle electronic components. The problem may have been corrected when the harness connections were re-engaged. Be certain that the ECM and chassis grounds are in good condition.
- Refer to the INTERMITTENT CONDITION - DIESEL Diagnostic Procedure. Intermittent Condition