2.2.58. SPN 157, FMI 16, Rail Pressure control: Pressure CRITICAL HIGH.ΒΆ

Description

The measured rail pressure is above the warning limit.

Possible causes are:

  • The high pressure pump is not working correctly.
  • The rail pressure sensor wiring is defective.
  • The rail pressure sensor power supply is not correct.
  • The rail pressure sensor is defective.

Reaction in EEM

The FC is stored and the warning lamp is activated. Engine power is heavily reduced (Degradation Level 3). The CAN message indicates an active fault. The engine functions dependent on the rail pressure are not active.

Solution

First save the error log and then do the procedure that follows:

  • Examine the high pressure pump: Look for possible high pressure pump faults and inspect them accordingly (e.g. faults with the wiring and the connectors)
  • Examine the high pressure pump operation, or have the pump inspected by an authorized Bosch service dealer.

To check the electrical defects, check the rail pressure sensor, the sensor wiring and the controller input:

  • Examine the rail pressure sensor wiring, the connectors and the contact surfaces of the connector pins (possible oxidation).
  • Make sure that the 5 V power supply to the rail pressure sensor is correct.
  • Try the operation with another rail pressure sensor to see if the rail pressure sensor is defective.

NOTE: The rail pressure sensor removal, inspection and replacement should be performed only by qualified injection system service personnel. Special instructions may apply.

See Rail pressure sensor for reference.