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 Descriptors

DTC P0230: Fuel Pump Relay Control Circuit

DTC P2632: Fuel Pump Relay 2 Control Circuit

Diagnostic Fault Information

DTC P0230

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

--

P0230

--

--

Fuel Pump Ground

--

²

--

--

¹Open fuel pump fuse, cranks no start

²Cranks no start

³Fuel pump operates continuously, then discharged battery

DTC P2632

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Battery Voltage - Relay Switch Side

¹

³

--

--

Fuel Pump Supply Voltage

¹

³

²

--

Fuel Pump Relay Control

P2632

P2632

P2632

--

Fuel Pump Relay Ground

--

P2632

--

--

Fuel Pump Ground

--

³

--

--

¹Open fuel pump fuse

²Fuel pump operates continuously, then discharged battery

³Fuel pump operates will not operate

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 when the above conditions are met.
    • DTC P2632 runs continuously when 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

DTCs P0230 and P2632 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0230 and P2632 are Type B DTCs.

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

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

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. With the ignition OFF, remove the affected fuel pump relay.
  2. With the ignition ON, engine OFF, probe the control circuit of the fuel pump relay with a test lamp that is connected to a good ground. Command the fuel pump relay ON and OFF with a scan tool. The test lamp should turn ON and OFF with each command.
  3. If the test lamp does not turn ON and OFF, test for an open, high resistance, or a short to ground in the fuel pump relay control circuit, an intermittent or a poor connection at the engine control module (ECM). If the circuit tests normal, replace the control module.
    If the test lamp remains illuminated with each command, test for a short to voltage in the control circuit of the fuel pump relay or an intermittent or a poor connection at the ECM. If the circuit tests normal, replace the control module.
  4. Connect a test lamp between the control circuit of the fuel pump relay and the ground circuit of the fuel pump relay. Command the fuel pump relay ON and OFF with a scan tool.
  5. If the test lamp does not turn ON and OFF, repair the open or the high resistance in the ground circuit of the fuel pump relay.
    If the test lamp does turn ON and OFF, test for an intermittent and for a poor connection at the fuel pump relay, or a faulty 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