Refer to
Cell 21: Fuel Controls
Circuit Description
The PCM provides ignition positive voltage to control the fuel pump relay. The PCM has the ability to detect an electrical malfunction on the relay control circuit. When the ignition switch is first turned on, the PCM energizes the fuel pump relay which applies power to the fuel pump. The fuel pump relay will remain on as long as the engine is running or cranking and the PCM is receiving reference pulses. If no reference pulses are present, the PCM de-energizes the fuel pump relay within 2 seconds after the ignition is turned on or the engine is stopped. With the engine stopped, the fuel pump can be turned on by using the scan tool output controls function. If an electrical malfunction is detected, the PCM will set DTC P0230.
Conditions for Running the DTC
| • | The ignition is on. |
| • | System voltage is between 9.0 and 16.0 volts. |
Conditions for Setting the DTC
| • | The PCM detects an electrical malfunction on the fuel pump relay control circuit. |
| • | The condition is present for 0.5 second. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed. |
| • | The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using the scan tool. |
Diagnostic Aids
An intermittent may be caused by a poor connection, rubbed through the wire insulation or a wire broken inside of the insulation. Refer to Intermittents and Poor Connections Diagnosis .
Check for the following conditions:
| • | Poor connections at the PCM or fuel pump relay. Refer to Intermittents and Poor Connections Diagnosis . |
| Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. Refer to Intermittents and Poor Connections Diagnosis Repairing Connector Terminals and Connector Repairs . |
| • | Damaged harness. Refer to Wiring Repairs . |
| Inspect the wiring harness for damage. Refer to Wiring Repairs . |
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Test Description
The numbers below refer to the step numbers on the diagnostic table:
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Ensures that the fuel pump relay control circuit and the PCM are capable of controlling the fuel pump relay. Using the scan tool to command the fuel pump allows only a 2 second time in the commanded state.
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Checks the fuel pump control circuit for a short to ground.
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Checks the fuel pump control circuit for an open.
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This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the on-Board (OBD) Diagnostic System Check? | -- | Go to Step 2 | |
Does the relay turn on and off with each command? | -- | Go to Diagnostic Aids | Go to Step 3 | |
Does the test lamp turn on and off with each command? | -- | Go to Step 4 | Go to Step 5 | |
4 |
Does the test lamp turn on and off with each command? | -- | Go to Step 8 | Go to Step 10 |
Does the test lamp remain illuminated with each command? | -- | Go to Step 7 | Go to Step 6 | |
6 | Test the control circuit of the relay for a short to ground or an open. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 |
7 | Test the control circuit of the relay for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 |
8 | Inspect for poor connections at the relay. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 |
9 | Inspect for poor connections at the PCM. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 |
10 | Repair the ground circuit of the relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 13 | -- |
11 | Replace the relay. Did you complete the replacement? | -- | Go to Step 13 | -- |
|
Important: : The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | Go to Step 13 | -- | |
13 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
