P0192

P0192-FUEL PRESSURE SENSOR LOW





For a complete wiring diagram Refer to Diagrams/Electrical.

Theory of Operation


The Electronic Control Module (ECM) provides a 5-volt supply to the fuel rail pressure sensor using a common sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The fuel rail pressure sensor provides a signal to the ECM on the fuel rail pressure sensor signal circuit. This sensor signal voltage changes based on the pressure in the fuel rail. The ECM will detect a low signal voltage at low rail pressures. The ECM will detect a high signal voltage during high rail pressure conditions. The ECM will light the MIL lamp immediately after the diagnostic runs and fails. During this time the customer may experience a power and or speed derate. The ECM will turn off the MIL light after the diagnostic runs and passes in 4 consecutive drive cycles.

- When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.

- Set Condition:
The circuit voltage to the ECM falls below a calibrated threshold for a certain period of time.







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


Diagnostic Test


1. OTHER DTC'S
Ignition on, engine not running.
With the scan tool, read DTCs.
Check for multiple DTC that may share the same 5-volt supply circuit and Sensor Ground circuit. Repair as necessary.
Do you have multiple DTC's?

Yes


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


No


- Go To2



2. (F855) 5-VOLT SUPPLY AND (K916) RETURN CIRCUIT




Turn the ignition off.
Disconnect the Fuel Pressure sensor harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Ignition on, engine not running.
Measure the voltage between the (F855) 5-volt supply and (K916) return circuits of the Fuel pressure sensor harness connector.
Is the voltage between 4.5 and 5.5 volts?

Yes


- Go To3


No


- Go To4



3. FUEL PRESSURE SENSOR
Reconnect the disconnected Fuel Pressure Sensor harness connector.
While monitoring scan tool, disconnect the Fuel Pressure sensor harness connector.
Does the DTC P0193 set?

Yes


- Replace the Fuel Pressure Sensor.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test


No


- Go To4



4. (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO (K916) RETURN CIRCUIT




Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the Fuel Pressure sensor harness connector.
Check connectors - Clean/repair as necessary.
Measure the resistance between the (F855) 5-volt supply circuit and (K916) return circuit in the sensor harness connector.
Is the resistance greater than 100k Ohms?

Yes


- Go To5


No


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



5. (K181) SIGNAL CIRCUIT SHORTED TO (K916) RETURN CIRCUIT




Measure the resistance between the (K181) signal circuit and (K916) return circuit in the sensor connector.
Is the resistance greater than 100k Ohms?

Yes


- Go To6


No


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



6. (K181) SIGNAL CIRCUIT OPEN




Measure the resistance between the signal (K181) circuit in the sensor harness connector with the (K181) signal circuit in the ECM harness connector.
Is the resistance less than 10 Ohms?

Yes


- Go To7


No


- Repair the open (K181) signal circuit.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



7. (F855) 5-VOLT SUPPLY CIRCUIT OPEN




Measure the resistance between the supply (F855) circuit in the sensor harness connector with the (F855) 5-volt supply circuit in the ECM harness connector.
Is the resistance less than 10 Ohms?

Yes


- Go To8


No


- Repair the open (F855) 5-volt supply circuit.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



8. (K181) SIGNAL CIRCUIT SHORTED TO GROUND




Measure the resistance between the (K181) signal circuit in the sensor harness connector and battery negative.
Is the resistance greater than 100k Ohms?

Yes


- Go To9


No


- Repair (K181) signal circuit shorted to ground.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



9. (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND




Measure the resistance between the (F855) 5-volt supply circuit in the sensor harness connector and battery negative.
Is the resistance greater than 100k Ohms?

Yes


- Go To10


No


- Repair (F855) 5-volt Supply circuit shorted to ground.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



10. ECM
Reconnect the disconnected Fuel pressure sensor harness connector and ECM harness connectors.
While monitoring scan tool, disconnect the Fuel Pressure sensor connector.
Does the DTC P0193 set?

Yes


- Test Complete.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test


No


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