P0191

P0191-FUEL RAIL PRESSURE SENSOR PERFORMANCE

P0191 - Fuel Rail Pressure Sensor Performance:

WHEN MONITORED
At key on.

SET CONDITION
The fuel pressure sensor reading at key on does not match the expected fuel pressure reading at key on.

POSSIBLE CAUSES
- Other DTC's present
- Fuel rail pressure sensor
- Fuel system tampering
- Intermittent condition

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. OTHER DTC'S PRESENT
With the scan tool, read DTCs.

Q: Are any DTC's present?

YES: Repair other DTC's first. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 2

2. FUEL PRESSURE READING
Using the scan tool, monitor the actual fuel pressure reading while the key is on and engine is not running.

Q: Is the actual fuel pressure reading greater than 870 psi?

YES: Go To 3
NO: Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure).

3. FUEL RAIL PRESSURE SENSOR
Visually inspect the fuel system components for signs of tampering, pay particular attention to the fuel pressure sensor on the fuel rail and the fuel pressure sensor wiring harness.

Q: Were any signs of tampering discovered?
NO: Replace the Fuel rail pressure sensor. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
YES: Restore Fuel system to original condition. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1