P129D 2018 GMC Sierra 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 GMC Sierra 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.
Code P129D 2018 GMC Sierra Description
What are the Possible Causes of the DTC P129D 2018 GMC Sierra?
- 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 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.
Code Tech Notes
2016-2018 Chevrolet Silverado 1500
2019 Chevrolet Silverado LD
Dead Battery / P1682 P129D P10E4 P2535 / Crank No Start
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What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P129D 2018 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.
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Frequently Asked Questions about P129D 2018 GMC Sierra Code
1. What does the OBDII code P129D mean for a 2018 GMC Sierra?
It indicates a low voltage issue in the Fuel Pump Driver Control Module Ignition On/Start Switch Circuit.
2. What are the common symptoms of the P129D code?
Symptoms include difficulty starting the engine, engine stalling, reduced fuel efficiency, or a no-start condition.
3. What causes the P129D code on a GMC Sierra?
Possible causes include a faulty fuel pump driver module, damaged ignition/start switch wiring, corroded connectors, or a weak battery.
4. Can a weak battery trigger the P129D code?
Yes, a weak or failing battery can cause low voltage issues that may trigger this code.
5. How can I diagnose the P129D code?
Inspect the wiring and connectors for damage or corrosion, test the battery voltage, and check the functionality of the fuel pump driver module.
6. Is the P129D code dangerous to drive with?
Yes, it can lead to engine stalling or a no-start condition, so it’s best to address it promptly.
7. How is the P129D code typically fixed?
Repairs may involve replacing the fuel pump driver module, repairing damaged wiring, cleaning corroded connectors, or replacing the battery.
8. Can a faulty ignition switch cause the P129D code?
Yes, a malfunctioning ignition switch can prevent proper voltage delivery, triggering this code.
9. Do I need a professional mechanic to fix the P129D code?
While some issues like checking battery voltage can be done at home, more complex repairs like module replacement may require professional assistance.
10. How much does it cost to repair the P129D code?
Costs vary depending on the issue, ranging from $50 for wiring repairs to $500 or more for a new fuel pump driver module.
Discuss the causes and fixes for P129D 2018 GMC Sierra OBDII Code
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