What causes fault code P0233?

• Most likely: Faulty fuel pump relay (pitted or burnt contacts) • Likely: Loose connection or corrosion in the fuel pump wiring harness/connectors • Possible: Wiring harness chafing against the chassis (intermittent short to ground) • Rare: Faulty Fuel Pump Driver Module (FPDM) or Engine Control Module (ECM)

Powertrain (Engine & Gearbox)Standard EOBD

P0233 - Fuel Pump Secondary Circuit Intermittent

Q: What are the symptoms of fault code P0233?

• Check engine light (MIL) illuminated • Engine stalls sporadically while driving • Intermittent hard start or no-start condition • Hesitation or jerking under load or during vibrations • Fuel pump may not prime consistently when ignition is turned on

Q: How do you fix fault code P0233?

STEP 1: Check the fuel pump relay. Swap it with a known good relay of the same type to test. Inspect the relay socket for signs of overheating or loose terminals. STEP 2: Perform a visual inspection of the wiring harness from the relay box to the fuel pump. Look for chafing, pinched wires, or corrosion in connectors. STEP 3: Perform a voltage drop test on the power supply circuit. Under load, it should be close to battery voltage (12.6V - 14.5V). Check fuel system ground points (resistance should be < 0.5 Ohms). STEP 4: Use an oscilloscope or a scan tool with live data to monitor the Fuel Pump Monitor signal while wiggling the harness to identify the intermittent break. STEP 5: If wiring and relay are sound, test the fuel pump current draw or replace the Fuel Pump Driver Module (FPDM).

Last updated:1 February 2026

Related:Fuel Pump, Fuel Pump, Fuel Pump Driver Module (FPDM), Engine Control Module (ECM/PCM), Wiring Harness

System

Powertrain (Engine & Gearbox)

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Technical Description

P0233 is set when the Engine Control Module (ECM) detects an intermittent voltage signal from the fuel pump secondary circuit (the monitor circuit). The ECM monitors the voltage on the output side of the fuel pump relay or fuel pump driver module to verify that the pump is receiving power when commanded. If the voltage feedback is inconsistent or drops out momentarily, the ECM triggers this code. This typically points to loose connections, a failing relay, or wiring harness vibrations causing temporary signal loss.

Possible Causes

Faulty fuel pump relay (pitted or burnt contacts)

Loose connection or corrosion in the fuel pump wiring harness/connectors

Wiring harness chafing against the chassis (intermittent short to ground)

Faulty Fuel Pump Driver Module (FPDM) or Engine Control Module (ECM)

Symptoms

Check engine light (MIL) illuminated

Engine stalls sporadically while driving

Intermittent hard start or no-start condition

Hesitation or jerking under load or during vibrations

Fuel pump may not prime consistently when ignition is turned on

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P0233 - Fuel Pump Secondary Circuit Intermittent

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P0233 - Fuel Pump Secondary Circuit Intermittent

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