AutoCodes – Chevrolet – P129D 2018 Chevrolet Silverado

P129D 2018 Chevrolet Silverado Code - Fuel Pump Driver Control Module Ignition On/Start Switch Circuit Low Voltage

Quick Answer

The Fuel Pump Power Control Module monitors the ignition voltage circuit to determine if the voltage is within the normal operating range. Common causes include Faulty Fuel Pump Power Control Module, Fuel Pump Power Control Module harness is open or shorted, Fuel Pump Power 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: P129D 2018 Chevrolet Silverado indicates Fuel Pump Driver Control Module Ignition On/Start Switch Circuit Low Voltage.
Common causes: Common causes include Faulty Fuel Pump Power Control Module, Fuel Pump Power Control Module harness is open or shorted, Fuel Pump Power 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 2,383

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 12, 2022

Description
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P129D 2018 Chevrolet Silverado Description

The Fuel Pump Power Control Module monitors the ignition voltage circuit to determine if the voltage is within the normal operating range. The Diagnostic Trouble Code (DTC) will be set when the Fuel Pump Power Control Module ignition switch circuit voltage is less than a calibrated value for 1 s.

OBDII Code P129D 2018 Chevrolet Silverado - Fuel Pump Driver Control Module Ignition On/Start Switch Circuit Low Voltage - AutoCodes.com — P129D 2018 Chevrolet Silverado Code - Fuel Pump Driver Control Module Ignition On/Start Switch Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P129D 2018 Chevrolet Silverado?

Faulty Fuel Pump Power Control Module
Fuel Pump Power Control Module harness is open or shorted
Fuel Pump Power Control Module circuit poor electrical connection

How to Fix the DTC P129D 2018 Chevrolet Silverado?

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 does this mean?

Code Tech Notes

There is a Factory Service Bulletin for the following Chevrolet models:
2016-2018 Chevrolet Silverado 1500
2019 Chevrolet Silverado LD
Dead Battery / P1682 P129D P10E4 P2535 / Crank No Start

User Submitted Video

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P129D 2018 Chevrolet Silverado 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 P129D 2018 Chevrolet Silverado code?

Need more information on how to fix the P129D 2018 Chevrolet Silverado code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P129D 2018 Chevrolet Silverado code diagnosed by a professional: Find a repair shop in your area

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 P129D 2018 Chevrolet Silverado Code

1. What does the OBDII code P129D mean for a 2018 Chevrolet Silverado?

P129D indicates a low voltage issue in the Fuel Pump Driver Control Module (FPCM) Ignition On/Start Switch Circuit, potentially affecting fuel pump operation.

2. What are the symptoms of the P129D code?

Symptoms may include difficulty starting the engine, reduced engine performance, or the engine failing to start.

3. What causes the P129D code to appear?

Common causes include a faulty Fuel Pump Driver Control Module, damaged wiring or connectors in the ignition/start circuit, or a failing ignition switch.

4. Can a weak battery cause the P129D code?

Yes, a weak or failing battery can result in insufficient voltage to the FPCM, triggering the P129D code.

5. How do you diagnose the P129D code?

Diagnosis involves checking the battery voltage, inspecting wiring and connectors for damage, testing the FPCM, and verifying proper function of the ignition switch.

6. Can I drive my Silverado with the P129D code active?

Driving with this code is not recommended, as it may lead to unpredictable engine performance or failure to start.

7. How do you fix the P129D code?

Repairs may include replacing the Fuel Pump Driver Control Module, repairing damaged wiring or connectors, or addressing battery and ignition switch issues.

8. Is the P129D code covered under warranty for the 2018 Chevrolet Silverado?

This depends on the specific warranty coverage for your vehicle. Check with your Chevrolet dealer for details.

9. Can a software update fix the P129D code?

In some cases, a software update for the powertrain control module (PCM) may resolve communication or voltage issues, but it depends on the specific circumstances.

10. How much does it cost to fix the P129D code on a Silverado?

Repair costs can vary widely, ranging from $100 for minor wiring repairs to $500 or more if the FPCM needs replacement.