Fuel System - MIL ON, DTC P0087, and Various Related Concerns
20 13 03April 15, 2013
2031426 *Supersedes T.B. V201302 dated January 16, 2012 to include M.Y. 2008 applicability, which allows archiving of technical bulletin V201101.*
Vehicle Information
Condition
High Pressure Fuel Pump Diagnosis
Engine Crank, No Start after Long Periods without Driving. Engine may run rough, and or MIL-ON with DTC P0087-low fuel pressure stored in ECM Fault Memory.
Technical Background
Completing the GFF high pressure pump function test is essential to diagnose proper pump operation and to avoid unnecessary replacements.
Production Solution
N/A
Service
The high pressure pump requires a sufficient supply of fuel pressure in order to operate properly.
^ Check for sufficient pressure at the low pressure pump as described in the repair manual, located under the headings: Engine -> Engine Mechanical, Fuel Injection and Ignition -> Fuel Supply System -> Diagnosis and Testing -> Fuel Pump, Checking -> Fuel Pressure, Checking.
Is low pressure fuel pump within specifications?
YES: Continue to high pressure fuel pump test.
NO: Replace low pressure fuel pump and continue.
Guided fault finding provides a function test for the high pressure fuel pump. This test must be performed in order to properly diagnose the high pressure fuel pump.
Note:
A completed high pressure fuel pump function test is required for reimbursement.
Following completion of the function test:
If the fuel rail pressure is within +/- 1 of 40 bar (580 psi.), DO NOT replace the high pressure fuel pump. Continue to further diagnose the fuel system, this bulletin does not apply.
^ With the engine running, check measure value blocks 106, 140 and 141 to confirm fuel rail pressure reads a minimum of 40 bar (480 psi).
The engine should be switched OFF and the key switched ON to perform the following procedure:
^ Enter vehicle self-diagnosis.
^ Select OBD.
^ Select 01 engine electronics.
^ Select 005 - output diagnostic test mode (DTM).
^ VAS will run diagnostics.
^ When the test starts to check operation of the "fuel pressure regulator 2 control circuit high" (figure 1), listen for an audible "click" sound coming from the N276 pressure regulator.
Tip:
The audible "click" sound may be better heard with hood open and the engine cover removed.
^ If "click" noise is heard, DO NOT replace the high pressure fuel pump, this bulletin will not apply. Continue to further diagnose the fuel system.
^ If "click" noise is not heard, and fuel rail pressure is below 10 bar, replace the high pressure fuel pump.
^ Following completion of the test procedure, the vehicle should be driven with higher RPMs (3000 - 5500) to confirm the fault does not return.
Warranty
Required Parts and Tools
Additional Information
All part and service references provided in this Technical Bulletin are subject to change and/or removal.
Always check with your Parts Dept. and Repair Manuals for the latest information.