P0629⛽ Fuel system / fuel pump control circuitStop and fix promptly

P0629: Fuel Pump A Control Circuit High (Meaning, Causes, Fixes)

Reviewed 2026-10-25 · Based on 2 cited source(s)

What P0629 means

The fuel pump moves fuel from the tank to the injectors, and its control circuit turns the pump on and off as the engine needs it. OBD-Codes.com says P0629 appears when a problem is found in the fuel pump "A" control circuit, specifically a higher than normal voltage condition, and it adds that an open in the circuit can also set this code. It is usually set by the engine computer (PCM or ECM), but OBD-Codes.com notes other modules, such as a fuel injection, alternative fuel or turbo control module, can also set it, and that it may take several drive cycles or set right away depending on the vehicle. RepairPal says the PCM sets P0629 when it detects that the fuel pump is not operating properly. The sources differ on emphasis: OBD-Codes.com points mainly to wiring, connectors, grounds and the CAN bus, with the pump itself as one cause, while RepairPal lists fuel pump failure first, adds PCM failure, and names fuel pump replacement as the common repair. They also differ on severity (moderately severe vs Urgent). Related codes include P0627 (circuit/open), P0628 (circuit low) and P062A (circuit range/performance), and on vehicles with a separate fuel pump control module, U0109 (lost communication with that module).

Severity: can I keep driving?

Stop and fix promptly

Get it checked soon and avoid long trips. RepairPal rates P0629 Urgent, meaning it can cause serious damage or leave you stranded. OBD-Codes.com calls it moderately severe: the car may still drive, but it strongly advises against it because fuel delivery can cut in and out, and an erratic fuel mixture could damage the engine. Either way, an engine that won't start or stalls in traffic is a real risk.

Common symptoms

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

  1. Failed fuel pump (OBD-Codes.com; RepairPal)
  2. Open, shorted or corroded wiring or connectors in the fuel pump control circuit, often under the car near the tank (OBD-Codes.com; RepairPal lists a wiring issue)
  3. Damaged or disconnected ground wire or ground strap at the control module (OBD-Codes.com)
  4. Open, shorted or corroded wiring in the CAN data bus, or a faulty CAN bus (OBD-Codes.com)
  5. High resistance in the circuit, such as melted or corroded connectors (OBD-Codes.com)
  6. Failed engine computer (PCM) (RepairPal)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

  1. Read all stored codes with a scan tool and note any communication (U) codes or other fuel codes that came with it (OBD-Codes.com).
  2. Look for technical service bulletins (TSBs) for your year, make and model; OBD-Codes.com says this can save a lot of time.
  3. Inspect the wiring and connectors near the fuel tank for road damage, chafing or corrosion (OBD-Codes.com).
  4. Check the battery terminals and grounds for corrosion and clean them if needed (OBD-Codes.com).
  5. If the car stalls or won't start, don't keep cranking it for long; have it towed rather than risk being stranded.

Typical fixes

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

  • Tracing the fuel pump control wire with a wiring diagram and a multimeter or power probe to find the open or short (OBD-Codes.com)
  • Testing module grounds with an auxiliary ground cable; if the fault clears with the extra ground, the original ground is bad (OBD-Codes.com)
  • Scanning every module to check the vehicle's overall electrical and network health (OBD-Codes.com)
  • The engine won't start or stalls while driving
  • The code returns after wiring repairs

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Is P0629 serious?

RepairPal rates it Urgent. OBD-Codes.com calls it moderately severe and says that although you may still be able to drive, you should avoid it because fuel delivery can become intermittent and an erratic fuel mixture could damage the engine. It can also cause stalling or a no-start.

Does P0629 always mean a bad fuel pump?

No. RepairPal lists fuel pump failure first and names pump replacement as the common repair, but OBD-Codes.com says the code is typically caused by damaged wiring or connectors in the control circuit or CAN bus, or by bad grounds. Checking the wiring and grounds before buying a pump can save money.

What is the difference between P0627, P0628 and P0629?

All three involve the fuel pump "A" control circuit. According to OBD-Codes.com's list of related codes, P0627 is control circuit/open, P0628 is control circuit low and P0629 is control circuit high.

How much does it cost to fix P0629?

Neither source gives a repair cost. It can range from fixing a corroded connector or ground to replacing the fuel pump, so get a diagnosis and a written estimate first.

Sources

  1. OBD-Codes.com: P0629 Fuel Pump A Control Circuit High (Patrick Cameron)
  2. RepairPal: P0629 Fuel Pump "A" Control Circuit High (rated Urgent)

Last reviewed 2026-10-25. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.