AutoCodes – GMC – P1229 GMC

P1229 GMC Code - Injector 3 Output Circuit

Quick Answer

The Engine Control Module (ECM) enables the appropriate fuel injector on the compression stroke for each cylinder. Common causes include Faulty Fuel Injector 3, Fuel Injector 3 harness is open or shorted, Fuel Injector 3 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: P1229 GMC indicates Injector 3 Output Circuit.
Common causes: Common causes include Faulty Fuel Injector 3, Fuel Injector 3 harness is open or shorted, Fuel Injector 3 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.

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Code Popularity 6,369

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 25, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P1229 GMC Description

The Engine Control Module (ECM) enables the appropriate fuel injector on the compression stroke for each cylinder. The ECM controls the Fuel Injection Control Module (FICM) by grounding the control circuit via a solid state device called a driver. The ECM monitors the state of the driver. If the ECM detects an incorrect voltage for the commanded state of an injector driver, Diagnostic Trouble Code (DTC) P1223, P1226, P1229, P1232, P1235, P1238, P1241, or P1244 will set.

OBDII Code P1229 GMC - Injector 3 Output Circuit - AutoCodes.com — P1229 GMC Code - Injector 3 Output Circuit

What does this mean?

What are the Possible Causes of the DTC P1229 GMC?

Faulty Fuel Injector 3
Fuel Injector 3 harness is open or shorted
Fuel Injector 3 circuit poor electrical connection
Faulty Fuel Injection Control Module (FICM)
Faulty Engine Control Module (ECM)

How to Fix the DTC P1229 GMC?

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

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

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1229 GMC 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 P1229 GMC 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.