Powertrain, generic · Computer and auxiliary outputs

P0628 Fuel Pump A Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

What 'fuel pump A control circuit' means differs by maker: at GM petrol 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 petrol 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. 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 petrol engines do not use P0628. A blown fuse is a frequent companion.

Likely causes

Control wire to relay or pump shorted to ground (chafing)
Relay coil shorted
Pump or pump module shorted internally (Ford high side)
Driver in the engine module faulty

Symptoms

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

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–700
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

fuel pump relayfuel pump driver modulefuel pumpengine control module

Related codes

P0627P0629P062AP0231P025A

References: law.cornell.edu, gsi.ext.gm.com, gsi.ext.gm.com, fordservicecontent.com.