GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    •  Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    •  Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0230: Fuel Pump Relay Control Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Battery Voltage - Relay Switch Side

¹

²

--

--

Fuel Pump Supply Voltage

¹

²

³

--

Fuel Pump Relay Control

P0230

P0230

P0230

--

Fuel Pump Relay Ground

--

--

--

--

Fuel Pump Ground

--

²

--

--

¹Open fuel pump fuse, cranks no start

²The engine cranks but does not run

³Fuel pump operates continuously, then discharged battery

Circuit/System Description

The control module enables the fuel pump relay when the ignition switch is turned ON. The control module will disable the fuel pump relay within 2 seconds unless the control module detects ignition reference pulses. The control module continues to enable the fuel pump relay as long as ignition reference pulses are detected. The control module disables the fuel pump relay within 2 seconds if ignition reference pulses cease to be detected and the ignition remains ON.

The control module monitors the voltage on the fuel pump relay control circuit. If the control module detects an incorrect voltage on the fuel pump relay control circuit, a fuel pump relay control DTC sets.

Conditions for Running the DTC

    • The ignition voltage is between 9-18 volts.
    • DTC P0230 runs continuously once the above conditions are met.

Conditions for Setting the DTC

    • The control module detects that the commanded state of the driver and the actual state of the control circuit do not match.
    • The above condition is met for a minimum of 2.5 seconds.

Action Taken When the DTC Sets

    • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

    • 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.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Engine Control Module Connector End Views
    •  Engine Controls Connector End Views
    •  Electrical Center Identification Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions
    •  Scan Tool Output Controls

Special Tools Required

J 43244 Relay Puller Pliers

Circuit/System Verification

With the ignition ON, engine OFF, command the fuel pump relay ON and OFF several times using the scan tool output control function. You should either hear or feel the relay click with each command.

Circuit/System Testing

  1. Ignition OFF, disconnect the affected fuel pump relay.
  2. Test for less than 5 ohms of resistance between the ground circuit and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Connect a test lamp between the control circuit of the fuel pump relay and the ground circuit of the fuel pump relay.
  5. Command the fuel pump relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
  6. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
    If the test lamp is always OFF, test the control circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the ECM.
  7. If all circuits test normal, test or replace the fuel pump relay.

Component Testing

  1. Measure for 70-110 ohms of resistance between terminals 85 and 86 of the fuel pump relay.
  2. If the resistance is not within the specified range, replace the fuel pump relay.
  3. Measure for infinite resistance between the following terminals of the fuel pump relay:
  4. • 30 and 86
    • 30 and 87
    • 30 and 85
    • 85 and 87
    If continuity is detected, replace the fuel pump relay.
  5. Connect a 20-amp fused jumper wire from the positive terminal of the battery to relay terminal 85. Connect a jumper wire from the negative terminal of the battery to relay terminal 86. Measure for less than 2 ohms between terminals 30 and 87 of the relay.
  6. If the resistance measures more than 2 ohms, replace the fuel pump relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Control Module References for ECM replacement, setup, and programming
    •  Relay Replacement