GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2003 🢒 VUE - AWD 🢒 Engine 🢒 Engine Controls - 3.0L (L81) 🢒 DTC P0629

Circuit Description

The engine control module (ECM) provides ignition 1 voltage to the coil side of the fuel pump relay. When you turn ON the ignition switch, the ECM energizes the fuel pump relay, which applies power to the fuel pump. The PCM applies a low current signal of approximately 7 volts to the fuel pump relay control circuit with the key ON and the engine OFF. The PCM uses this signal to detect the integrity of the fuel pump relay control circuit. The ECM enables the fuel pump relay as long as the engine is cranking or running, and crankshaft reference pulses are received. If no crankshaft reference pulses are received, the ECM de-energizes the fuel pump relay after 2 seconds. The ECM monitors the voltage on the fuel pump relay control circuit. If the ECM detects an incorrect voltage on the fuel pump relay control circuit, a fuel pump relay control DTC sets.

Conditions for Running the DTC
    • The engine speed is more than 40 RPM.
    • The system voltage is between 7.5-15 volts.

Conditions for Setting the DTC
    • The ECM detects an incorrect voltage on the control circuit of the fuel pump relay .
    • The condition exists more than 1 second.

Action Taken When the DTC Sets
    • The control module stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
    • The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC
    • 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 non-emission related diagnostic.
    • Clear the DTC with a scan tool.

Diagnostic Aids

Fuel Relay Underhood Bussed Electrical Center Terminal Identification

Right side of vehicle

Ground

Fuel pump supply

Left side of vehicle

--

Battery positive voltage

Control

--

Front of vehicle

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step verifies that the ECM is providing voltage to the fuel pump relay.

    2.

  2. This step tests for an open in the ground circuit to the fuel pump relay.

    3.

  3. This step tests if voltage is constantly being applied to the control circuit of the fuel pump relay.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Turn ON the ignition, with the engine OFF.

    2. Important: An audible click should be heard.

  2. Command the fuel pump ON and OFF with a scan tool.

Does the fuel pump relay turn ON and OFF with each command?

Go to Step 3

Go to Step 4

3
  1. Observe the Freeze Frame/Failure Records data for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Attempt to start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text or as close to the Freeze Frame/Failure Records that you observed.

Does the DTC fail this ignition?

Go to Step 4

Go to Intermittent Conditions

4

  1. Turn OFF the ignition.
  2. Disconnect the fuel pump relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the control circuit of the fuel pump relay with a test lamp connected to a good ground. Refer to Diagnostic Aids.
  5. Command the fuel pump ON and OFF with a scan tool.

Does the test lamp turn ON and OFF with each command?

Go to Step 5

Go to Step 6

5

  1. Connect a test lamp between the control circuit of the fuel pump relay and the ground circuit of the relay.
  2. Command the fuel pump ON and OFF with a scan tool.

Does the test lamp turn ON and OFF with each command?

Go to Step 9

Go to Step 11

6

Does the test lamp remain illuminated with each command?

Go to Step 8

Go to Step 7

7

Test the control circuit of the fuel pump relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 9

8

Test the control circuit of the fuel pump relay for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 10

9

Inspect for poor connections at the fuel pump relay. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

10

Inspect for poor connections at the harness connectors of the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 13

11

Repair the open in the ground circuit of the relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

--

12

Replace the fuel pump relay.

Did you complete the replacement?

Go to Step 14

--

13

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

Go to Step 14

--

14
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 15

15

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK