The engine control module (ECM) monitors fuel rail pressure (FRP) using the fuel rail pressure sensor. If the sensor indicates a pressure less than the commanded rail pressure plus a possible transitional overshoot, the ECM will set diagnostic trouble code (DTC) P0087 for fuel rail pressure too low.
• | DTCs P0192, P0193, or P1635 are not set. |
• | The ignition is ON. |
The actual fuel rail pressure is less than 0.0 MPa at 0-400 RPM.
OR
The actual fuel rail pressure is less than 22.5 MPa at more than 600 RPM.
• | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
• | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records. |
• | The ECM will shut off fuel injection if DTC P0087 is current. |
• | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
• | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
• | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
• | Clear the MIL and the DTC with a scan tool. |
A restricted fuel supply line may cause DTCs P0087 and P0093 to set at the same time. Refer to Fuel System Diagnosis .
The numbers below refer to the step numbers on the diagnostic table.
If the fuel temperature is high enough to set DTC P0168, the fuel may be thin enough to cause this DTC to set.
The engine will not start if the fuel leak is large enough.
This step checks for an inaccurate fuel rail pressure sensor.
This step checks for fuel leaks into the engine oil.
This step checks for a restriction in the fuel system between the fuel injection pump and the fuel tank.
This test checks to see if the fuel injection pump is able to supply maximum fuel pressure at idle. The fuel injection pump should be able to create 158 MPa at idle.
This step checks for a restriction in the fuel system between the fuel injection pump and the fuel tank that may only cause symptoms at higher engine speed and load conditions.
This step checks to see if the fuel rail pressure sensor wiring and ECM are functioning normally.
If the vacuum is still too high in the fuel supply system after replacing the fuel filter, there is a restriction in the fuel supply lines or sending unit in the fuel tank.
Step | Action | Values | Yes | No |
---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
Is DTC P0168 or P0090 also set? | -- | Go to Step 3 | ||
Attempt to start the engine. Does the engine start and idle? | -- | Go to Step 4 | ||
Is the Actual Fuel Rail Pressure Parameter within the specified range? | 1-1.8 MPa | Go to Step 5 | Go to Step 10 | |
Check the engine oil for fuel contamination. Refer to Fuel in Engine Oil in Engine Mechanical. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 6 | |
Does the vacuum measure less than the specified value through the entire RPM range? | 5 in | Go to Step 7 | Go to Step 11 | |
Is the Actual Fuel Rail Pressure parameter more than the specified value? | 145 MPa | Go to Step 8 | ||
Important: If the fuel temperature is near 121 °C (250 °F) during the duplication of the complaint (or in the Failure Records for this DTC), check for a restriction in the fuel cooler air flow or the fuel heater always ON. Refer to Fuel Heater Always On .
Does the vacuum measure less than the specified value through the entire operating range? | 12 in | Go to Step 9 | Go to Step 11 | |
9 | Ask the customer if there has been a power-enhancing device attached to the fuel rail pressure sensor circuits. What was the customers answer? | -- | Go to Step 17 | |
Does the Actual Fuel Rail Pressure measure more than the specified value? | 175 MPa | Go to Step 15 | Go to Step 14 | |
11 | Replace the fuel filter. Refer to Fuel Filter Replacement . Did you compete the replacement? | -- | Go to Step 12 | -- |
Does the vacuum measure less than or equal to the specified value? | 5 in at idle or 12 in at high speed | Go to Step 17 | Go to Step 13 | |
13 | Repair the restriction in the fuel supply lines between the fuel tank and the fuel injection pump. Refer to Fuel System Diagnosis . Did you complete the repair? | -- | Go to Step 17 | -- |
14 | Check the fuel rail pressure sensor signal circuit for a short to ground. repair as necessary. Refer to Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 16 |
15 | Replace the fuel rail pressure sensor. Refer to Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 17 | -- |
16 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 17 | -- |
17 |
Does the DTC run and pass? | -- | Go to Step 18 | Go to Step 2 |
18 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK |