P0653

P0653-SENSOR REFERENCE VOLTAGE 2 HIGH

For complete wiring diagrams refer to Diagrams/Electrical.


Theory of Operation

This sensor supply circuit provides a 5 volt supply to: 1. Engine position sensor 2. Intake manifold temperature/pressure sensor 3. Exhaust pressure sensor 4. Fuel pressure sensor 5. Ambient temperature/pressure sensor 6. EGR valve 7. Fan clutch assembly 8. Crankcase pressure sensor A MIL lamp will be lit immediately after this diagnostic runs and fails. The MIL lamp will turn off once the diagnostic runs and passes in 4 consecutive drive cycles.

- When Monitored:

While the engine is running.

- Set Condition:

Voltage detected on the sensor supply is above a calibrated value.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test


1. ECM

Turn the ignition off.

Disconnect the ECM 60 pin harness connector.


NOTE: Check connectors - Clean/repair as necessary.

Turn the ignition on.

Measure the voltage between the Sensor (F855) #1 5-volt Supply and the Sensor #1 Return pin at the ECM.

Is the voltage between 4.5 and 5.5 volts?

Yes

- Go To 2

No

- Replace and program the ECM.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

2. (F855) 5-VOLT SUPPLY SHORTED TO VOLTAGE

Key off.

Disconnect the sensor connectors for each pressure sensor, and the engine position sensor.

Disconnect the ECM 50 way harness connector.


NOTE: Check connectors - Clean/repair as necessary.

Ignition on, engine off.

Measure the voltage between the supply circuit at each pressure sensor harness connector and battery negative.

Measure voltage between the (F855) 5-volt supply circuit at the engine position sensor harness connector and battery negative.

Is the voltage less than 1 volt?

Yes

- Go To 3

No

- Repair the (F855) 5-volt supply shorted to voltage.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

3. SENSOR SUPPLY SHORTED TO VOLTAGE IN HARNESS

Measure the resistance between the #1 sensor supply circuit and all other circuit in the ECM connectors.

Is the resistance less than 10 ohms?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

No

- Repair the harness shorted to voltage.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test