EngineLightCodes
Powertrain code

P0628 Fuel Pump A Control Circuit Low

Severity
Fix soon
Typical repair cost
$20–$770
Do it yourself
Possible, medium
Shop time
0.5–3 hours

What 'fuel pump A control circuit' means differs by maker: at GM gasoline engines it is the control line from the engine module to the fuel pump relay (high-side driver), at GM's LML diesel the lift pump, at Ford gasoline engines with a pump driver module the secondary circuit from that module to the pump (reported as a duty cycle on a monitor line), and at Ford's 6.7 L diesel (F-650/750) the high or low side of the pump relay.

How the engine computer detects it

P0628 means a short to ground: GM detects 0.5 Ω or less to ground with the driver on (8 of 10 samples at 250 ms; two trips in 2018, first trip in 2025); the driver then shuts off, the relay does not pull in and the pump stops. Ford's 6.7 L diesel reports a short to ground on the high side of the pump relay within 0.2 s. Ford gasoline engines do not use P0628. A blown fuse is a frequent companion.

Written from public technical sources and not yet checked by a mechanic. How we write these pages

Symptoms

  • No start or stalling
  • Pump does not run
  • Blown fuse
  • Check engine light on

Common causes

  1. Control wire to relay or pump shorted to ground (chafing) Most likely
  2. Relay coil shorted Possible
  3. Pump or pump module shorted internally (Ford high side) Possible
  4. Driver in the engine module faulty Less likely

How to diagnose P0628

  1. Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
  2. Inspect the parts involved: fuel pump relay, fuel pump driver module, fuel pump, engine control module.
  3. Work through the causes above from most to least likely, cheapest checks first.
  4. Clear the code and drive a full drive cycle to confirm the repair held.

Reading the code

P
Powertrain
0
Generic (SAE) code
6
Computer and output circuits
28
Specific fault

Questions drivers ask

Can I drive with code P0628?

Usually yes for a short time, if the car drives normally, the temperature gauge reads normal and the check engine light is steady. If the light flashes, the engine loses power or overheats, or other warning lights come on, pull over and have it checked.

Will my car pass an emissions inspection with P0628?

Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.

Will P0628 clear by itself?

The light can go off after several drive cycles without the fault, but the code returns if the cause is still there. After a repair, the readiness monitors need a full drive cycle before an inspection.

Can I fix P0628 myself?

Often yes, with an OBD-II scanner and basic tools. Difficulty: medium. Start with the cheapest checks before replacing expensive parts.

This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.