Engine-CodesGMC – P0629 2017 GMC Sierra

P0629 2017 GMC Sierra Code - Fuel Pump Speed Output Circuit High Voltage

Quick Answer

The P0629 diagnostic trouble code (DTC) for a 2017 GMC Sierra indicates a problem with the Fuel Pump Speed Output Circuit High Voltage. Common causes include Faulty fuel pump speed sensor, Damaged wiring or connectors in the fuel pump speed output circuit, Malfunctioning ECM. 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 2017 GMC Sierra indicates Fuel Pump Speed Output Circuit High Voltage.
Common causes
Common causes include Faulty fuel pump speed sensor, Damaged wiring or connectors in the fuel pump speed output circuit, Malfunctioning ECM.
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.
Table of contents Created and updated by William Orellana on Sep 16, 2024
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Code P0629 2017 GMC Sierra Description

The P0629 diagnostic trouble code (DTC) for a 2017 GMC Sierra indicates a problem with the Fuel Pump Speed Output Circuit High Voltage. This code is set when the Engine Control Module (ECM) detects that the voltage signal from the fuel pump speed sensor is higher than normal, indicating a potential issue with the fuel pump speed output circuit. The fuel pump speed sensor is responsible for monitoring the speed of the fuel pump to ensure proper fuel delivery to the engine.

OBDII Code P0629 2017 GMC Sierra - Fuel Pump Speed Output Circuit High Voltage
P0629 2017 GMC Sierra Code - Fuel Pump Speed Output Circuit High Voltage

Common Causes of P0629 2017 GMC Sierra

  1. Faulty fuel pump speed sensor
  2. Damaged wiring or connectors in the fuel pump speed output circuit
  3. Malfunctioning ECM
  4. Defective fuel pump
  5. Corrosion or contamination in the fuel system

Symptoms of P0629 2017 GMC Sierra

  1. Engine misfires
  2. Hesitation during acceleration
  3. Stalling or difficulty starting
  4. Reduced fuel efficiency
  5. Check Engine Light illuminated

How to Fix P0629 2017 GMC Sierra

  1. Diagnose the issue by using a scan tool to retrieve the DTC and inspecting the fuel pump speed sensor, wiring, and connectors.
  2. Test the fuel pump speed sensor for proper operation and replace if necessary.
  3. Check the wiring and connectors for damage or corrosion, repairing or replacing as needed.
  4. Inspect the fuel pump for any defects or malfunctions and replace if required.
  5. Clear the DTC and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0629 2017 GMC Sierra

The typical repair costs for addressing a P0629 code on a 2017 GMC Sierra can range from $200 to $500, including parts and labor. However, it's important to note that specific diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. Most auto repair shops charge between $80 and $150 per hour for labor, with rates potentially higher in metropolitan areas or at dealerships, and lower at independent shops. To obtain a more accurate estimate, it's recommended to check local rates before proceeding with the repair.

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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 2017 GMC Sierra Code

What does the OBDII code P0629 mean on a 2017 GMC Sierra?

P0629 indicates that the Fuel Pump Speed Output Circuit is experiencing high voltage, which may affect the fuel pump's operation.

What are the common symptoms of a P0629 code in a 2017 GMC Sierra?

Symptoms may include difficulty starting, engine stalling, reduced engine performance, or the check engine light being illuminated.

What causes the P0629 code on a 2017 GMC Sierra?

Common causes include a faulty fuel pump relay, wiring issues like short circuits or damaged connectors, a malfunctioning fuel pump, or a defective powertrain control module (PCM).

Can I drive my 2017 GMC Sierra with a P0629 code?

While the vehicle may still be drivable, it's not recommended as the issue could lead to engine stalling or further damage to the fuel system.

How can I diagnose the P0629 code on my GMC Sierra?

Start by checking the fuel pump relay and inspecting all related wiring and connectors for damage or corrosion. Use a multimeter to test for proper voltage at the circuit.

How do I fix the P0629 code on a 2017 GMC Sierra?

Repairs may include replacing a faulty fuel pump relay, repairing damaged wiring or connectors, replacing the fuel pump, or reprogramming or replacing the PCM if necessary.

How much does it cost to repair a P0629 code on a 2017 GMC Sierra?

Repair costs vary based on the cause. Replacing a fuel pump relay might cost $50-$150, while replacing the fuel pump or PCM could exceed $500.

Can a bad fuel pump cause the P0629 code to appear?

Yes, a malfunctioning fuel pump can cause high voltage in the circuit and trigger the P0629 code.

Will clearing the P0629 code solve the issue in my GMC Sierra?

Clearing the code may turn off the check engine light temporarily, but the underlying issue must be addressed to prevent the code from returning.

Can a failing PCM cause the P0629 code on a 2017 GMC Sierra?

Yes, a defective PCM can misinterpret or send incorrect signals, resulting in the P0629 code. However, this is less common and should be diagnosed last.

Discuss the causes and fixes for P0629 2017 GMC Sierra OBDII Code

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