Engine-CodesGMC – P1229 GMC

P1229 GMC Code - Injector 3 Output Circuit

Quick Answer

The P1229 GMC code specifically refers to an issue with the Injector 3 Output Circuit in the vehicle's fuel injection system. Common causes include Faulty fuel injector, Damaged wiring or connectors in the injector circuit, Issues with the engine control module (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
P1229 GMC indicates Injector 3 Output Circuit.
Common causes
Common causes include Faulty fuel injector, Damaged wiring or connectors in the injector circuit, Issues with the engine control module (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 10, 2024
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Code P1229 GMC Description

The P1229 GMC code specifically refers to an issue with the Injector 3 Output Circuit in the vehicle's fuel injection system. This code indicates that there is a problem with the electrical circuit that controls the fuel injector for cylinder 3. The fuel injector is responsible for delivering the correct amount of fuel into the combustion chamber, ensuring proper engine performance and efficiency.

OBDII Code P1229 GMC - Injector 3 Output Circuit
P1229 GMC Code - Injector 3 Output Circuit

Common Causes of P1229 GMC

  1. Faulty fuel injector
  2. Damaged wiring or connectors in the injector circuit
  3. Issues with the engine control module (ECM)
  4. Vacuum leaks affecting fuel mixture
  5. Fuel pressure problems

Symptoms of P1229 GMC

  1. Rough idling or engine misfires
  2. Decreased fuel efficiency
  3. Engine stalling or difficulty starting
  4. Check Engine Light illuminated
  5. Loss of power or acceleration

How to Fix P1229 GMC

  1. Use a scan tool to retrieve the trouble code and confirm the issue is related to the Injector 3 Output Circuit.
  2. Inspect the wiring and connectors for any damage or corrosion. Repair or replace as necessary.
  3. Test the fuel injector for proper operation and replace if faulty.
  4. Check fuel pressure to ensure it is within specifications.
  5. Clear the trouble code and test drive the vehicle to verify that the issue has been resolved.

Cost to Fix P1229 GMC

The cost of repairing the Injector 3 Output Circuit can vary depending on the specific cause of the issue and the labor rates in your area. In general, you can expect to pay anywhere from $150 to $500 for parts and labor. Keep in mind that rates at dealerships or in metropolitan areas may be higher, while independent shops may offer more competitive pricing. It's recommended to obtain quotes from multiple shops to ensure you are getting a fair price for the repair.

Tech Notes for P1229 GMC

If only 1 fuel injector Control circuit Diagnostic Trouble Code (DTC) is set, an open circuit or poor connection is the most likely cause. If groups of 4 fuel injector Control circuit DTCs are set, suspect a short to ground. Cylinder groups are 2, 3, 5, 8 or 1, 4, 6, 7. More than 4 fuel injector Control circuit DTCs set indicate short to voltage on fuel injector Control circuit is the most likely cause.



There is a factory service bulletin for the following models:



2004 GMC Sierra

2005 GMC Sierra

2004 GMC Topkick

2005 GMC Topkick

2004-2005 GMC Sierra, Topkick Factory Service Bulletin OBDII Code P1229

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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.

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