AutoCodes – GMC – P0629 2014 GMC Sierra

P0629 2014 GMC Sierra Code - Fuel Pump Speed Output Circuit High Voltage

Quick Answer

The Engine Control Module (ECM) supplies voltage to the fuel pump driver control module for 30 s when the ignition is on and continuously when the engine is running. Common causes include Faulty Fuel Pump Driver Control Module, Fuel Pump Driver Control Module harness is open or shorted, Fuel Pump Driver Control Module circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0629 2014 GMC Sierra indicates Fuel Pump Speed Output Circuit High Voltage.
Common causes
Common causes include Faulty Fuel Pump Driver Control Module, Fuel Pump Driver Control Module harness is open or shorted, Fuel Pump Driver Control Module circuit poor electrical connection.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
AI answers can be wrong. Verify repairs with testing. Open full chat
Code Popularity 555
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Jul 15, 2022
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Code P0629 2014 GMC Sierra Description

The Engine Control Module (ECM) supplies voltage to the fuel pump driver control module for 30 s when the ignition is on and continuously when the engine is running. While this voltage is being received, a serial data signal containing the desired fuel pump speed is also received from the ECM. After the voltage and data have been received the fuel pump driver control module actuates the brushless fuel pump by means of a high power three phase signal. The Diagnostic Trouble Code (DTC) will be set when the Fuel Pump Speed Output Circuit is short to voltage for greater than 2 s.
OBDII Code P0629 2014 GMC Sierra - Fuel Pump Speed Output Circuit High Voltage - AutoCodes.com
P0629 2014 GMC Sierra Code - Fuel Pump Speed Output Circuit High Voltage

What are the Possible Causes of the DTC P0629 2014 GMC Sierra?

  • Faulty Fuel Pump Driver Control Module
  • Fuel Pump Driver Control Module harness is open or shorted
  • Fuel Pump Driver Control Module circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

How to Fix the DTC P0629 2014 GMC Sierra?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0629 2014 GMC Sierra code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0629 2014 GMC Sierra code?

Need more information on how to fix the P0629 2014 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0629 2014 GMC Sierra Code

What does the OBDII code P0629 mean on a 2014 GMC Sierra?

P0629 indicates a problem with the Fuel Pump Speed Output Circuit, specifically detecting a high voltage condition.

What are the common symptoms of a P0629 code?

Symptoms may include difficulty starting the engine, reduced fuel efficiency, engine stalling, or the Check Engine Light being illuminated.

What causes a P0629 code to be triggered?

Causes can include a faulty fuel pump relay, damaged wiring or connectors in the fuel pump circuit, a malfunctioning fuel pump control module, or a short circuit.

Can I drive my 2014 GMC Sierra with a P0629 code?

It is not recommended to drive with this code as it could lead to engine stalling or further damage to the fuel system.

How do I diagnose a P0629 code?

Diagnosis involves checking the fuel pump relay, inspecting wiring and connectors for damage, testing the fuel pump control module, and using a multimeter to measure circuit voltages.

What tools are needed to diagnose and repair a P0629 code?

You may need an OBDII scanner, a digital multimeter, wiring diagrams, and basic hand tools for inspection and testing.

How can a P0629 code be fixed?

Repairs may include replacing a faulty fuel pump relay, repairing damaged wiring, replacing the fuel pump control module, or addressing any circuit shorts or opens.

Is the P0629 code specific to the 2014 GMC Sierra?

No, the P0629 code is a generic OBDII code that can appear in other vehicles, but its specific causes and symptoms may vary by make and model.

How much does it typically cost to fix a P0629 code?

Repair costs can range from $50 to $500 or more, depending on the underlying issue, such as replacing a relay, repairing wiring, or replacing the control module.

Can a P0629 code be cleared without repairs?

The code can be cleared with an OBDII scanner, but it will likely return if the underlying issue is not resolved.

Discuss the causes and fixes for P0629 2014 GMC Sierra OBDII Code

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