Open circuit, short to ground or chafed wiring in the fuel pump control circuit; Corroded, loose or damaged connectors at the fuel pump, relay, fuel pump control module or ECU; Faulty fuel pump relay or its socket; Failing fuel pump drawing excessive current or shorting internally; Faulty fuel pump control module (on vehicles that have one); Blown fuse or poor power or earth supply to the pump circuit; Fault inside the engine control unit driver circuit.

P0628

Fuel Pump A Control Circuit Low.

Generic
Powertrain
Generic code
High severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
6: AreaComputer and output circuits
28: FaultThe specific fault in that area

What it means

P0628 is the generic code for a low voltage or low signal state in the fuel pump A control circuit. The engine control unit (or a separate fuel pump control module, depending on the vehicle) commands the pump and monitors the control circuit. When the voltage it sees is lower than expected for the commanded state, it sets this code.

Symptoms

Engine cranks but does not start
Long cranking before the engine fires
Engine stalls or cuts out, especially when warm
Loss of power or hesitation under load
Malfunction indicator lamp on
Intermittent starting problems

Possible causes

Open circuit, short to ground or chafed wiring in the fuel pump control circuitlikely
Corroded, loose or damaged connectors at the fuel pump, relay, fuel pump control module or ECUlikely
Faulty fuel pump relay or its socketpossible
Failing fuel pump drawing excessive current or shorting internallypossible
Faulty fuel pump control module (on vehicles that have one)possible
Blown fuse or poor power or earth supply to the pump circuitpossible
Fault inside the engine control unit driver circuitrare

How to diagnose

Read all stored codes and freeze frame data to see engine conditions, and note any related fuel pressure or pump module codes
Check the relevant fuse and relay, and swap the relay with a known good identical one if the layout allows
Inspect the wiring and connectors from the ECU or pump module to the pump, looking for chafing, corrosion, water ingress or heat damage, particularly near the fuel tank and underbody
Check for battery voltage and a good earth at the pump and relay while it is commanded on, following the wiring diagram for the specific model
Test the control circuit for continuity and for short to ground with the connectors disconnected
Measure fuel pump current draw and compare it with the manufacturer specification
Check fuel pressure against specification, using the method for that engine
If wiring and pump check out, test the pump control module or ECU driver output following manufacturer procedures

How to fix

Repair or replace damaged wiring and clean or renew corroded connectors
Replace a faulty fuel pump relay or fuse after finding out why it failed
Replace the fuel pump if it draws excessive current or is not delivering the correct pressure
Replace or reprogram the fuel pump control module if testing confirms it is faulty
Restore poor power or earth connections to the pump circuit
Replace the ECU only after all other causes are ruled out, and have it coded as required

Can I keep driving?

High severity

Avoid driving the car if it is stalling, hesitating or hard to start, as losing fuel delivery can cause a sudden loss of power in traffic. If it runs normally, get it checked as soon as possible because it may fail to restart.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.