Fuel Pump Secondary Circuit High
P0232 indicates the PCM detected abnormally high voltage in the fuel pump relay secondary (feedback) circuit. This circuit allows the PCM to monitor fuel pump relay operation, and a high voltage condition suggests a short to voltage or relay driver malfunction that could prevent proper fuel pump control.
What You Might Notice
- Check Engine Light (MIL) illumination
- Fuel pump runs continuously with ignition off
- Engine may crank but not start due to fuel pump control issues
- Fuel pump noise or abnormal operation
- Possible fuel smell near the vehicle
Most Common Causes
- 1
Faulty fuel pump relay
The relay contacts or internal circuit may be shorted, causing voltage to remain present on the feedback circuit even when the relay should be de-energized.
- 2
Short to voltage in fuel pump circuit wiring
The fuel pump voltage supply or feedback circuit wire may be shorted to battery voltage, sending an abnormal signal back to the PCM.
- 3
PCM fuel pump relay driver failure
The PCM's internal relay control driver may be damaged or shorted to ground, preventing proper relay de-energization and causing voltage feedback issues.
- 4
Corroded or damaged relay connections
Poor connections at the fuel pump relay socket or terminals can cause intermittent shorts or voltage spikes on the feedback circuit.
How to Diagnose It
- 1
Check Faulty fuel pump relay — The relay contacts or internal circuit may be shorted, causing voltage to remain present on the feedback circuit even when the relay should be de-energized.
- 2
Check Short to voltage in fuel pump circuit wiring — The fuel pump voltage supply or feedback circuit wire may be shorted to battery voltage, sending an abnormal signal back to the PCM.
- 3
Check PCM fuel pump relay driver failure — The PCM's internal relay control driver may be damaged or shorted to ground, preventing proper relay de-energization and causing voltage feedback issues.
- 4
Check Corroded or damaged relay connections — Poor connections at the fuel pump relay socket or terminals can cause intermittent shorts or voltage spikes on the feedback circuit.
How to Fix It
- 1
Test and replace fuel pump relay
Using a multimeter, test the fuel pump relay for proper operation and continuity. If faulty, disconnect the relay and replace it with an OEM or quality aftermarket unit, then clear the code and test drive.
- 2
Inspect fuel pump circuit wiring and connectors
Visually inspect the fuel pump relay wiring harness, connectors, and the fuel pump circuit for signs of shorts, damage, or corrosion. Repair or replace damaged wiring and clean corroded connections.
- 3
Check fuel pump relay socket and contacts
Remove the fuel pump relay and inspect the relay socket pins for corrosion, bent terminals, or burn marks. Clean terminals thoroughly or replace the socket if damaged.
- 4
Perform PCM diagnostics or replacement
If wiring and relay tests pass, the PCM relay driver circuit may be internally damaged. Have the PCM tested by a professional or replace it if the internal driver is confirmed faulty.
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