Corroded, loose, or damaged electrical connector at the fuel pump control module; Open or chafed wire in the secondary fuel pump circuit (power or ground side); Failed fuel pump control module (often located near the fuel tank); Failed fuel pump assembly with an open internal circuit; Blown fuse or faulty relay in the fuel pump power supply; Poor ground connection for the fuel pump or control module; Water intrusion or corrosion in the wiring harness near the fuel tank

DTC codes / P02xx · Fuel and air metering (injector circuits) / P023F

P023FFuel Pump Secondary Circuit/Open

Q: What does code P023F mean?

Fuel Pump Secondary Circuit/Open. P023F indicates that the powertrain control module (PCM) has detected an open circuit or excessive resistance in the secondary side of the fuel pump electrical circuit, which typically includes the fuel pump control module, wiring, and ground path. The PCM monitors voltage or current on this circuit and sets the code when the signal falls outside the expected range, often disabling the fuel pump or forcing it to run at full speed as a fail-safe.

P023F indicates that the powertrain control module (PCM) has detected an open circuit or excessive resistance in the secondary side of the fuel pump electrical circuit, which typically includes the fuel pump control module, wiring, and ground path. The PCM monitors voltage or current on this circuit and sets the code when the signal falls outside the expected range, often disabling the fuel pump or forcing it to run at full speed as a fail-safe.

SystemPowertrain

Code typeGeneric (all makes)

SeverityHigh

Fix difficultyProfessional

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Engine cranks but fails to start because the fuel pump is not receiving power
Engine stalls shortly after starting or during driving
Reduced engine power or limp mode due to fuel delivery issues
Audible fuel pump not priming when the ignition is turned on
In rare cases, the engine may run normally if the fault is intermittent

Common causes, most likely first

Corroded, loose, or damaged electrical connector at the fuel pump control module
Open or chafed wire in the secondary fuel pump circuit (power or ground side)
Failed fuel pump control module (often located near the fuel tank)
Failed fuel pump assembly with an open internal circuit
Blown fuse or faulty relay in the fuel pump power supply
Poor ground connection for the fuel pump or control module
Water intrusion or corrosion in the wiring harness near the fuel tank

How to diagnose and fix it

Inspect the fuel pump fuse and relay, and replace if blown or faulty
Check for stored codes and freeze-frame data to confirm the fault conditions
Visually inspect the fuel pump control module connector and wiring for corrosion or damage
Perform a voltage drop test on the secondary fuel pump circuit to locate excessive resistance
Test the fuel pump control module with a multimeter or oscilloscope for proper output signal
If the module is faulty, replace and reprogram as necessary
If the pump is faulty, replace the fuel pump assembly and verify fuel pressure

Don't overlook the fuel pump control module

A common misdiagnosis is replacing the fuel pump when the actual fault is a corroded connector at the control module, which is often overlooked because it is hidden above the fuel tank.
P023F can be set by a failing fuel pump control module even when the pump itself is good, so testing the module's output signal is critical before condemning the pump.
Intermittent open circuits caused by chafed wiring near the fuel tank can set P023F without any drivability symptoms, leading to unnecessary parts replacement.
Some vehicles use a pulse-width modulated (PWM) signal to control fuel pump speed, and a scope is often needed to see a distorted signal that a basic multimeter misses.
A weak battery or charging system fault can cause low voltage to the control module, triggering P023F even though the fuel pump circuit is intact.

Can I keep driving with P023F?

If the engine stalls or fails to start, do not continue driving because the vehicle may become stranded or cause a safety hazard. If the check engine light is on but the engine runs normally, drive cautiously to a repair shop, avoiding heavy loads or high speeds.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.