P0629 OBD-II Trouble Code: Fuel Pump "A" Control Circuit High

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0629 code

P0629 is a diagnostic trouble code (DTC) for "Fuel Pump "A" Control Circuit High". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P0629 DIAGNOSTIC Get a fair and transparent estimate upfront

P0629 code definition

When the vehicle’s PCM stores the P0629 code, it means that there is an issue with the “A” control circuit in the fuel pump.

What the P0629 code means

Either the vehicle’s PCM, or another supporting control module, has found a problem with the fuel pump’s “A” control circuit. The supporting control modules include, but are not limited to:

  • Body control module
  • Fuel injection control module
  • Alternative fuel control module
  • Turbo control module
  • Anti-lock brake control module
  • Anti-theft module
  • Traction control module
  • Cruise control module
  • Instrument panel control module
  • Climate control module
  • Proximity alert module

What causes the P0629 code?

If the fuel pump “A” control circuit is faulty, the P0629 code is stored. This often means that the malfunction is in a certain area of the system, as opposed to any one component or circuit. Usually, the P0629 code is caused by a defective fuel pump, or a problem with the fuel pump relay. Other causes include:

  • Bad connectors, or shorted or open wiring in the CAN bus harness
  • A loose ground strap in the control module
  • A broken ground wire in the control module
  • A defective CAN bus

What are the symptoms of the P0629 code?

Symptoms of the P0629 code can include: * The code being stored

If the Check Engine Light does not come on right away, the code may be pending.

How does a mechanic diagnose the P0629 code?

The mechanic will focus on the CAN (controller area network) bus. This is what allows the various microcontrollers in the vehicle to communicate independent of a host computer. These microcontrollers regulate practically all of the vehicle’s electrical functions, and the PCM is the master controller.

It is possible for individual controllers to fail, but not common. So first, the mechanic will test each individual module, and replace as needed. The process starts with using an OBD-II scanner, and continues with several (but not necessarily all) of the following:

  • Visually checking connectors and wiring
  • Replacing any damaged wires, connectors and components
  • Re-testing the system
  • If all appears to be working properly, recording the codes and freeze frame data, and then clearing out the codes
  • Running the vehicle to see if the codes come back (if they don’t come back immediately, the problem could be intermittent and more difficult to diagnose)
  • Using a special scanner like Tech II or Autohex to identify the general area in which the problem is occurring
  • Disconnecting and testing all the CAN bus pins (this could be costly)
  • Testing control module ground circuits with battery ground
  • Identifying ground discrepancies using an auxiliary ground cable
  • Checking for corroded or loose connectors that could be increasing circuit resistance
  • Using a digital volt ohmmeter to test individual controller connector continuity, using a CAN bus wiring diagram and pin out value chart
  • Comparing findings with the manufacturer’s specs, and repairing shorted or open circuits as needed

Common mistakes when diagnosing the P0629 code

Repairs are sometimes unsuccessful if the communication failure is misdiagnosed. This is because the wrong component has been identified, and unnecessarily replaced.

How serious is the P0629 code?

This is not a life-threatening issue, but if not corrected, it could lead to more serious problems down the road. You do not have to get the problem fixed immediately, but should have it dealt with in order to avoid more expensive repairs later on.

What repairs can fix the P069 Code?

A mechanic can fix or replace damaged wiring and corroded connectors, and replace any defective modules.

Additional comments for consideration regarding the P0629 code

This type of problem often takes a long time to diagnose, and the wiring harnesses that need to be evaluated and/or repaired are very complex. Often, it is more cost-effective to simply replace any wiring that is suspect.

Need help with a P0629 code?

At YourMechanic, it will be our pleasure to send a mobile mechanic to your home or place of work. We will be glad to provide you with a free quote as well. To arrange an appointment, call us 1-800-701-6230, or use our convenient online form.

trouble codes
P0629
Check Engine Light

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0629 code.

SCHEDULE P0629 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

5,626

Rating Summary
5,199
206
50
34
137
5,199
206
50
34
137

Robert

11 years of experience
104 reviews
Robert
11 years of experience
Nissan Quest - Check Engine Light is on - Alexandria, Virginia
Punctual. Knowledgeable. Professional. Empathic, went the extra mile to explain in lay words the mechanical jargon. Excellent manners and customer service oriented. Client’s best interest and safety was always his top priority. From now on your company has in me a client for life. Thanks Robert!!!! 

Chris

21 years of experience
1861 reviews
Chris
21 years of experience
Mercedes-Benz E320 - Check Engine Light is on - Ladera Ranch, California
Chris was friendly, professional and knowledgeable. He got to the point of my concerns, explained what he was finding on his system and gave me his recommendations. I fully appreciate him taking the time to explain everything and a bit of history on my vehicle. Thanks again Chris.

Michael

15 years of experience
574 reviews
Michael
15 years of experience
Hyundai Accent - Check Engine Light is on - Marietta, Georgia
I had a great experience with Michael. He's extremely professional, friendly, and understands his craft. Highly recommended.

Chris

15 years of experience
274 reviews
Chris
15 years of experience
Dodge Durango - Check Engine Light is on - San Diego, California
Showed up early, was a friendly dude, kept me informed via text, did clean work and finished early. Would hire again.


More related articles

P0623 OBD-II Trouble Code: Generator Lamp Control Circuit
P0623 means there is a voltage problem between the ECU and the generator control module due to bad battery or alternator, or a weak or dead battery.
P2613 OBD-II Trouble Code: A/C Refrigerant Distribution Valve Control Circuit High
P2613 means a problem with the A/C refrigerant distribution valve control circuit which causes the air conditioning to not work properly.
P3400 OBD-II Trouble Code: Cylinder Deactivation System Bank 1
P3400 trouble code definition The P3400 diagnostic trouble code indicates that there is a performance issue with the Cylinder Deactivation System in...

Related questions

rough idle

Hello. I would need to know which misfire codes you are getting to know for sure what is going on. Most of the time on this vehicle if it is a single cylinder misfire then it may be as simple...

Check Engine Light and code for O2 sensor

Hello. Knowing the actual code number would help determine the problem. If you are getting an O2 sensor code associated with the way it is running, then the sensor is more than likely bad. On this Toyota, the O2 sensor...

Check Engine light back on

The two code are for two different issues and if both codes were not fixed, or after the repairs the engine self learn was not reset, then the light may come back on and the car not run correctly. I...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com