P023F: Fuel Pump Secondary Circuit/Open

What does P023F mean?

The fuel pump circuit has two sides: the primary circuit is the engine module's output to the fuel pump relay coil (or to a pump control module), the secondary circuit is the power circuit from relay contact or module to the pump itself. P023F means the power circuit to the pump is open. GM pumps with their own power module, whose speed is controlled by rail pressure, measure the pump current: if it stays below 1 A (older modules 0.5 A) although the pump is commanded, the code sets with the warning light in the first trip, and fuel pressure diagnostics are suspended. The cause lies in the wire from module to pump or its return, the pump connector or the pump motor itself. The pump stops, so the engine will not start or dies – there is no limp mode.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Engine does not start, no pump noise
• Engine stalls while driving
• Check engine light on

Common causes

• High Pump connector at tank flange or pump module open or corroded
• High Fuel pump open internally (brushes, winding)
• Medium Wire from module to pump or return wire open
• Low Pump control module faulty

Likelihood is a general estimate across vehicles; your make and model may differ.