P0087

P0087-FUEL RAIL PRESSURE TOO LOW





For complete wiring diagrams refer to Diagrams/Electrical.


Theory of Operation

The ECM will turn on the MIL lamp immediately after this diagnostic runs and fails. The ECM will turn off the MIL lamp after the diagnostic runs and passes in 4 consecutive drive cycles.

- When Monitored:

Engine running

- Set Condition:

Actual fuel pressure differs from setpoint more than a calibrated amount for a calibratable amount of time.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test


1. OTHER DTC'S

With the scan tool, read DTC's.

Are any other injector/fuel pressure related DTC's present?

Yes

- Troubleshoot other injector/fuel pressure related DTC's first.

No

- Go To 2

2. EXTERNAL FUEL LEAKS

Put on personal protective equipment.

Operate engine at idle when looking for fuel leaks.

Use the scan tool to operate engine at a variety of engine speeds.

Any external leaks detected?

Yes

- Repair or replace component with external fuel leak.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go to 3

3. FUEL PRESSURE LIMITING VALVE

Using the scan tool, view the pressure limiting valve counter and pressure limiting valve timer.

Is the counter value higher than 50 or the timer value higher than 5 hours?

Yes

- Change the pressure limiting valve. When valve replacement is complete, in scan tool go to PCM Misc Functions and Reset Two-Stage Dump Valve Accumulators.
- The fuel pressure limiting valve popping is sometimes a symptom of another fuel system problem.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
- Go To 4

No

- Go To 4

4. FUEL PRESSURE LIMITING VALVE

Turn key switch off. Remove the banjo bolt from the pressure limiting valve drain on the fuel rail. Install fuel system test fitting #9012 into the drain. Attach one end of a fuel hose to the fuel fitting and put the other end of the fuel hose into a container. Perform the tests listed below to determine if the pressure limiting valve is leaking.

a. Operate the engine at idle and watch for fuel flow into the container.

b. Operate the engine at idle and actuate the high pressure safety valve test with the scan tool.

Watch for fuel flow into the fuel container.

Does fuel flow into the container under either operating conditions?

Yes

- Change the pressure limiting valve. When valve replacement is complete, use the scan tool to reset the pressure limiting valve counter and timer. This command is in the PCM Misc Functions.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 5

5. IN TANK LIFT PUMP

Perform In-Tank Fuel Lift Pump Flow/Diagnostic Test Procedure. In-Tank Fuel Lift Pump Flow/Diagnostic Test Procedure

Does the lift pump pass the In-Tank Fuel Lift Pump Flow/Diagnostic Test Procedure?

Yes

- Go To 6

No

- Replace Lift Pump
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

6. HIGH PRESSURE PUMP

Perform Fuel Pump Return Flow Test. Fuel Pump Return Flow Test


NOTE: Part of this test requires that the Pressure Limiting Valve leakage is checked. This work was already performed in step 4.


NOTE: This test can be performed at the same time as the Injector Return Flow test that is listed in step 8 by measure the flow that is normally wasted.

Is the drain flow measured less than 1000 ml/minute at idle?

Yes

- Go To 7

No

- Replace fuel injection pump
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

7. HIGH PRESSURE PUMP

Perform High Pressure Fuel Pump Performance Test. High Pressure Fuel Pump Performance Test

Is the fuel flow above the specification?

Yes

- Go To 8

No

- Replace appropriate component as per High Pressure Fuel Pump Performance Test tree.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

8. INJECTOR RETURN FLOW TEST

Perform the Injector Return Flow Test. Injector Return Flow Test

Does the injector drainage meet the test specification?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

No

- Repair cause of high injector leakage
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test