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P0191

Read the instructions below then start the fault diagnostic procedure.

Symptom: CHECK ENGINE. Loss of performance.

P0191


Fuel Rail Pressure Sensor Circuit. Performance Problem.



Fault symptoms


• CHECK ENGINE.

• Loss of performance.


On-Board Diagnostics

Type of diagnosis:


- Continuous.


Enable criteria:

The following conditions must be fulfilled when the engine is started:


- Engine speed between 50-300 rpm.

- Fuel pressure greater than 15 MPa.

- >5 mm 3 /combustion.

- DTCs P0192, P0193, P1636, P1637 not active.


The following conditions must be fulfilled when the engine is running:


- Engine speed greater than 500 rpm.

- Fuel pressure greater than 15 MPa.

- >5 mm 3 /combustion.

- Fuel temperature lower than 110 °C.

- Pump compensation value should not exceed 140 Ca.

- DTCs P0192, P0193, P1636, P1637 not active.


Fault criteria:


- The difference between actual fuel pressure and desired fuel pressure is more than 20 MPa and the change in voltage across the sensor between two measurements falls below a transition of 80 mV when the control module requests an increase/decrease in pressure.


Dependents:


- P0181, P0183, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P1200, P0200, P0216, P0255, P0254, P0258, P0259


System reaction to a fault:


- Substitute value for fuel pressure is equal to the calculated value. The following limitations apply: Pedal position sensor adjustable to max 30 %, fuel quantity max 20 mm 3 /combustion, fuel rail pressure max 40 MPa, idling speed set to 1000 rpm and EGR control switched off.


OK report:


- Fault criteria not fulfilled.


Fault handling: (See section Fault handling III, other emissions-related components and functions for more information)


- Type III.


Diagnostic help

Fault diagnosis concerns an electrical fault in connecting leads or in the sensor.

Functions in the diagnostic tool related to the fault:


- Read value: Target Fuel Pressure, Fuel Pressure ( Fuel Pressure Sensor)


See also description of read value under "Read Values" menu for more information.

Checking the wiring

Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.