GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The engine control module (ECM) provides a ground to the coil side of the fuel pump relay. When the ignition switch is first turned On, the ECM energizes the fuel pump relay, which applies power to the fuel pump. 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 3 seconds. If the ECM detects low voltage on the fuel pump relay control circuit, this DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0230 Fuel Pump Relay Control Circuit Low Voltage

Conditions for Running the DTC

    • The ignition is ON or the engine is running.
    • The ignition voltage is more than 10 volts.
    • DTC P0230 runs continuously once the above conditions are met.

Conditions for Setting the DTC

    • The ECM detects that the commanded state of the driver and the actual state of the driver do not match.
    • The above conditions are present for more than 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.

Diagnostic Aids

The following conditions may have caused the fuel pump fuse to open:

    • The fuse is faulty.
    • There is an intermittent short to ground in the ignition 1 voltage circuit of the fuel pump relay.

Listen for a click when the fuel pump relay operates. When the fuel pump relay is commanded On with the scan tool, the ECM pulses the fuel pump relay ON and OFF several times.

For an intermittent condition, refer to Intermittent Conditions .

Fuel Pump Relay Terminal Identification

FP Motor

FP Control

Ignition 1 Voltage

B+

Front of Vehicle

Test Description

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

  1. Listen for a click when the fuel pump relay operates. When the fuel pump relay is commanded On with the scan tool, the ECM pulses the fuel pump relay ON and OFF several times. Repeat the command as necessary.

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

  2. This step tests the Ignition 1 Voltage 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. Command the fuel pump ON with a scan tool.

Does the fuel pump relay turn ON and OFF?

Go to Step 3

Go to Step 4

3

  1. Observe the Freeze Frame/Failure Records for this DTC.
  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 4

Go to Diagnostic Aids

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 battery voltage.
  5. Command the fuel pump ON with a scan tool.

Does the test lamp pulse ON and OFF?

Go to Step 5

Go to Step 6

5

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

Does the test lamp pulse ON and OFF?

Go to Step 7

Go to Step 9

6

Test the control circuit of the fuel pump relay for one of the following conditions:

    • An open
    • A short to ground
    • High resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 8

7

Test for an intermittent and for a poor connection at the fuel pump relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 10

8

Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 11

9

  1. Repair one of the following conditions in the ignition 1 voltage circuit of the fuel pump relay:
  2. • An open
    • High resistance
    • An intermittent short to ground. Refer to Wiring Repairs in Wiring Systems.
  3. Replace fuse as necessary.

Did you complete the repair?

Go to Step 12

--

10

Replace the fuel pump relay.

Did you complete the replacement?

Go to Step 12

--

11

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

Go to Step 12

--

12

  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 13

13

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