DTC P0087, P0088, or P0089
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DTC P0087, P0088, or P0089
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DTC P0087
Fuel Rail Low Pressure
DTC P0088
Fuel Rail High Pressure
DTC P0089
Fuel Pressure Regulator Performance
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Circuit/System Description
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The fuel rail pressure sensor detects fuel pressure within the fuel rail. The engine control module (ECM) provides a 5 V reference voltage on the 5 V reference circuit and ground on the low reference circuit. The ECM receives a varying signal voltage on the signal circuit.
High pressure fuel is regulated by the high pressure fuel pump actuator, which is a part of the high pressure fuel pump. The high pressure fuel pump actuator is a solenoid valve. The ECM provides battery voltage on the actuator high control circuit and ground on the actuator low control circuit. Both circuits are controlled through output drivers within the ECM. When deactivated, both drivers are disabled. When activated, the high control circuit driver energizes the high pressure fuel pump actuator and the low control circuit driver pulse-width modulates (PWM) the low control 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 high pressure fuel pump actuator 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 fuel rail.
The ECM creates a feedback loop between the pressure sensor and the high pressure fuel pump actuator. If the difference between expected and actual inputs exceeds a calibrated value, or if the amount of correction exceeds a calibrated value, a DTC sets.
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Conditions for Running the DTC
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DTCs P0090, P0091, P0092, P0192, P0193 are not set.
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The ignition 1 signal parameter is less than 18.1 V.
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The relative injected fuel mass is between 5.016-500%.
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The deceleration fuel cut-off is inactive.
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The engine speed is greater than 25 RPM.
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The engine start temperature is greater than -48°C (-54.4°F)
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The DTCs run continuously when the above conditions are met for 2 s.
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Conditions for Setting the DTC
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P0087
The actual fuel pressure is 1500 kPa (218 psi) less than the desired fuel pressure.
P0088
The actual fuel pressure is 2000 kPa (290 psi) greater than the desired fuel pressure.
P0089
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The fuel pressure adjustment is greater than +2,500 kPa (+363 psi) or less than -2,500 kPa (-363 psi).
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The DTCs set when the above conditions are met for 5 s.
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Action Taken When the DTC Sets
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DTCs P0087, P0088, and P0089 are Type B DTCs.
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A message center or an indicator displays Reduced Engine Power when DTC P0087 sets.
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Conditions for Clearing the DTC
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DTCs P0087, P0088, and P0089 are Type B DTCs.
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A restricted fuel feed pipe between the fuel feed pipe fuel pressure sensor and the high pressure fuel pump may set a DTC.
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A condition with the fuel tank fuel pump module or the fuel pump flow control module may set a DTC.
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A skewed fuel rail pressure sensor, or an intermittent condition in the fuel rail pressure sensor circuits may set a DTC.
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A leaking or restricted fuel injector may set a DTC.
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Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Fuel System Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
for scan tool information
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Circuit/System Verification
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1.
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If any other DTCs are set, perform those diagnostics first.
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2.
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Operate the vehicle within the parameters described in Conditions for Running and Conditions for Setting. The DTC should not set this ignition.
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3.
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If the DTC sets this ignition, proceed with Circuit/System Testing.
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Note
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Circuit/System Verification must be performed first or misdiagnosis may result.
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2.
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Remove the G18 High Pressure Fuel Pump and visually inspect the lobes on the camshaft for wear.
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3.
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If the lobes are normal, replace the G18 High Pressure Fuel Pump.
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4.
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If the lobes are worn, replace the camshaft.
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Static Test
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1.
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Ignition OFF, disconnect the harness connector at the high pressure fuel pump.
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2.
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Note
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The DMM and test leads must be calibrated to 0 Ω in order to prevent misdiagnosis.
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Test for 0.35-0.6 Ω at 20°C (68°F) of resistance between low control circuit terminal 1 and high control circuit terminal 2.
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3.
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If the resistance is less than 0.3 Ω or greater than 0.6 Ω, replace the high pressure fuel pump.
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4.
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Test for infinite resistance between each terminal and the high pressure fuel pump housing/case.
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5.
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If not the specified value, replace the high pressure fuel pump.
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Dynamic Test
Engine idling, command the Fuel Pressure Control to Increase with a scan tool. The Fuel Rail Pressure Sensor parameter should increase with each command.
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
