AutoCodes – GMC – P2691 GMC

P2691 GMC Code - Cylinder 6 Injector Data Incompatible

Quick Answer

The control functions for the fuel injection system are integrated into the Engine Control Module (ECM). Common causes include Program Injector, Faulty 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: P2691 GMC indicates Cylinder 6 Injector Data Incompatible.
Common causes: Common causes include Program Injector, Faulty 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.

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Code Popularity 1,236

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 01, 2021

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P2691 GMC Description

The control functions for the fuel injection system are integrated into the Engine Control Module (ECM). Each injector's flow rate information and cylinder position are stored in the memory of both the Glow Plug Control Module (GPCM) and the ECM. The fuel injector flow rate programming must be done when any of the following procedures are performed: The ECM is replaced, the GPCM is replaced, or any fuel injectors are replaced.
If the ECM does not communicate, the flow rate information can be retrieved from the GPCM. If both control modules fail to communicate, the fuel injector flow rate information, or Injection Quantity Adjustment (IQA) flow rate numbers, will need to be retrieved from each injector. The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the end of line injector adjustment code for cylinder 1 to 8 has not been programmed successfully after injector replacement.

OBDII Code P2691 GMC - Cylinder 6 Injector Data Incompatible - AutoCodes.com — P2691 GMC Code - Cylinder 6 Injector Data Incompatible

What does this mean?

What are the Possible Causes of the DTC P2691 GMC?

Program Injector
Faulty Engine Control Module (ECM)

How to Fix the DTC P2691 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

Programming Injector must perform with an OBDII scanner capable of programming injectors.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P2691 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.

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Need Help with the 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.

Frequently Asked Questions about P2691 GMC Code

1. What are the common symptoms of OBDII code P2691 in a GMC vehicle?

- Common symptoms include rough idling, engine misfires, decreased fuel efficiency, and the illumination of the Check Engine light.

2. What can cause the OBDII code P2691 (Cylinder 6 Injector Data Incompatible) to appear in a GMC vehicle?

- This code typically appears when there is an issue with the fuel injector in cylinder 6, such as a faulty injector, wiring problem, or ECU communication error.

3. How can I diagnose the OBDII code P2691 in my GMC vehicle?

- Diagnosis involves using a scan tool to read the code, checking the fuel injector in cylinder 6 for proper operation, inspecting the wiring for any damage, and verifying ECU communication.

4. What are the potential repair options for resolving OBDII code P2691 in a GMC vehicle?

- Repair options may include replacing the faulty fuel injector in cylinder 6, repairing any damaged wiring, resetting the ECU, or updating the ECU software to resolve the data incompatibility.

5. Can I continue to drive my GMC vehicle with the OBDII code P2691 present?

- It is not recommended to drive your vehicle with this code present, as it can lead to further engine damage and poor performance. Get the issue diagnosed and repaired as soon as possible.

6. Are there any preventive maintenance tips to avoid encountering OBDII code P2691 in a GMC vehicle?

- Regularly servicing and inspecting your vehicle, including the fuel system components, can help prevent issues like injector malfunctions that can trigger this code.

7. How much does it typically cost to repair OBDII code P2691 in a GMC vehicle?

- Repair costs can vary depending on the exact cause of the code, but it may range from $200 to $600 or more, including parts and labor.

8. Is it possible to reset the OBDII code P2691 in a GMC vehicle without fixing the underlying issue?

- While you can clear the code using a scan tool, it will likely reappear if the root cause, such as a faulty injector, is not addressed.

9. Can a DIY enthusiast fix OBDII code P2691 in a GMC vehicle, or is it recommended to seek professional help?

- Depending on your experience and knowledge, you may be able to diagnose and repair the issue yourself. However, seeking professional help is advised for a more accurate and reliable fix.

10. How long does it take to repair OBDII code P2691 in a GMC vehicle?

- The repair time can vary based on the specific issue causing the code, but it may take anywhere from 1 to 4 hours or more to diagnose and fix the problem.