P0087
DTC P0087, P0088, or P0089
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0087
- Fuel Rail Pressure (FRP) Too Low
DTC P0088
- Fuel Rail Pressure (FRP) Too High
DTC P0089
- Fuel Pressure Regulator Performance
Circuit/System Description
The fuel rail pressure sensor detects fuel pressure within the fuel rail. The engine control module (ECM) provides a 5 volt reference voltage on the 5 volt reference circuit and ground on the low reference circuit. The ECM receives a varying signal voltage on the signal circuit.
High fuel pressure is regulated by the fuel rail pressure (FRP) regulator, which is a part of the high pressure fuel pump. The FRP regulator is a solenoid valve. The ECM provides battery voltage on the FRP regulator high circuit and ground on the FRP regulator low circuit. Both circuits are controlled through output drivers within the ECM. When deactivated, both drivers are disabled. When activated, the ECMs high circuit driver energizes the FRP regulator and the low circuit driver pulse-width modulates (PWM) the low circuit to ground.
The high pressure mechanical fuel pump is driven by three lobes on the camshaft. The ECM uses the camshaft and crankshaft position sensor inputs to synchronize the FRP regulator with the position of each of these camshaft lobes. The ECM regulates fuel pressure by adjusting the portion of each pump stroke that provides fuel to the rail.
The ECM monitors the fuel pressure sensor and the FRP regulator to determine if the commanded and actual pressure are within a predetermined range, or if the amount of fuel pressure correction exceeds a calibrated pressure.
Conditions for Running the DTC
P0087, P0088, P0089
* DTC P0090, P0091, P0092, P0191, P0192, or P0193 is not set.
* The engine is operating.
* The high pressure fuel system is being regulated.
* The amount of injected fuel is within a predetermined range.
* DTCs P0087, P0088, and P0089 run continuously when the above conditions are met for 5 seconds, or 22 minutes when the ECM detects the vehicle is out of fuel.
P0087 Abort Auto-Start Test
* Before the ECM can report DTC P0087 failed, DTC P0090, P0091, P0092, P0191, P0192, P0193, P0627, P0628, or P0629 must run and pass.
* The high pressure fuel system is being regulated.
* The desired fuel rail pressure at auto-start is greater than 8000 kPa (1,160 psi) and the engine coolant temperature (ECT) is less than 90°C (194°F).
OR
* The desired fuel rail pressure at auto-start is greater than 4000 kPa (580 psi) and the engine coolant temperature (ECT) is greater than 89°C (192°F).
* The engine was operating for greater 3 seconds since the previous auto-stop, 2 seconds when the ECT is greater than 20°C (68°F).
* DTC P0087 runs once at auto-start when the conditions above are met.
Conditions for Setting the DTC
P0087
The actual fuel rail pressure is 1,500 kPa (218 psi) less than the desired fuel pressure.
P0088
The actual fuel rail pressure is 3,500 kPa (508 psi) greater than the desired fuel rail pressure.
P0089
* The fuel rail pressure regulator command necessary to maintain the desired fuel rail pressure is +/-2,500 kPa (363 psi) of the command expected by the controller.
* DTCs P0087, P0088, and P0089 set when the above conditions are met for 5 seconds.
Action Taken When the DTC Sets
* DTCs P0087, P0088, and P0089 are Type A DTCs.
* A message center or an indicator displays Reduced Engine Power.
Conditions for Clearing the DTC
DTCs P0087, P0088, and P0089 are Type A DTCs.
Diagnostic Aids
* A condition with the fuel tank module or the fuel pump control module (FPCM) may set these DTCs.
* A skewed fuel rail pressure (FRP) sensor, or an intermittent condition in the FRP sensor circuits will set these DTCs.
* Faulty fuel injectors may set DTC P0089.
Reference Information
Schematic Reference
Engine Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Fuel System Description (Fuel System Description)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Observe the DTC information with a scan tool. DTC P029D, P02A1, P02A5, P02A9, P02AD, P02B1, P0627, P0628, P0629, P0642, P0652, P0698, P069E, or U0109 should not be set.
• If a DTC is set refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).
2. Observe the fuel pump control module (FPCM) DTC information with a scan tool. Verify FPCM DTC P0191, P0192, P0193, P0231, P0232, P023F, P025A, P0601-P0604, P0606, P06A6, P062F, P0641, P064A, P1255, P2534, or P2635 is not set.
• If a DTC is set refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).
3. Attempt to start and idle the engine.
4. Observe the DTC information with a scan tool. DTCs P0087, P0088, and P0089 should not set.
Note: This step only tests the high pressure fuel pump located on the engine, not supply pressure from the in-tank fuel pump.
5. Engine idling, observe the Actual Fuel Rail Pressure parameter with a scan tool. The pressure should be approximately 3.5-5.5 Mpa (508-798 psi).
6. Command an increase and decrease in the fuel rail pressure with a scan tool. Observe the scan tool Actual Fuel Rail Pressure parameter. The Actual Fuel Rail Pressure should increase or decrease with each commanded state.
7. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Note: Circuit/System Verification must be performed first or misdiagnosis may result.
1. Ignition OFF, open the hood to disable the Auto-Stop function.
2. Ignition ON, verify the scan tool hood position parameter displays Open.
• If the hood position does not display Open, refer to DTC P254F (P254F).
Note: This step only tests the supply pressure from the in-tank fuel pump.
3. Ignition ON, observe the FPCM fuel line pressure sensor scan tool parameter. Command an increase in the fuel line pressure with a scan tool. Verify the fuel line pressure increases to greater than 410 kPa (60 psi) as commanded.
• If less than the specified range, refer to Fuel System Diagnosis (Fuel System Diagnosis).
Note: 2 ohm on either circuit of fuel pressure regulator (FRP) solenoid will set a DTC. Test the circuits of the FRP solenoid for a high resistance if you suspect a condition.
4. Remove the high pressure fuel pump assembly and visually inspect the lobes on the camshaft for unusual wear.
• If the lobes appear normal, replace the high pressure fuel pump assembly.
• If the lobes are worn, replace the camshaft.
Component Testing
Static Test
1. Ignition OFF, disconnect the harness connector at the high pressure fuel pump.
Note: The DMM and test leads must be calibrated to 0 ohm in order to prevent misdiagnosis.
2. Test for 0.3-0.7 ohm at 20°C (68°F) between FRP regulator circuit terminal 1 and circuit terminal 2.
• If not within the specified range, replace the high pressure fuel pump.
3. Test for infinite resistance between each terminal and the high pressure fuel pump housing.
• If not the specified value, replace the high pressure fuel pump.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Camshaft Removal - Left Side (LY7/LP1) (Overhaul)Camshaft Removal - Left Side (LCS) (Overhaul)
* Fuel Pump Replacement (Service and Repair)