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AutoCodes – GMC – P12B7 GMC

P12B7 GMC Code - Cylinder 3 Injection Timing Related

Quick Answer

The Engine Control Module (ECM) has the ability to learn injector timing performance. Common causes include Contaminated or improper fuel quality, Worn base engine components or differences in cylinder compression, Faulty Fuel Injector. 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
P12B7 GMC indicates Cylinder 3 Injection Timing Related.
Common causes
Common causes include Contaminated or improper fuel quality, Worn base engine components or differences in cylinder compression, Faulty Fuel Injector.
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 1,206
How popular is this code, among other codes? Low
What is this?
Table of contents Created and updated by William Orellana on Sep 11, 2019
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Code P12B7 GMC Description

The Engine Control Module (ECM) has the ability to learn injector timing performance. With the engine at operating temperature and in closed throttle decel mode, the ECM will pulse each injector individually and measure the changes in rotational speed of the crankshaft using the input from the Crankshaft Position Sensor (CPS). The ECM will run this diagnostic under three different fuel rail pressures for each injector. The ECM will adjust the timing of fuel delivered by each injector to obtain the desired RPM increase. The ECM stores the injector timing value required to increase the crankshaft speed by the desired RPM. If the ECM cannot control an increase in RPM for a given injector the appropriate code will set for that injector.
OBDII Code P12B7 GMC - Cylinder 3 Injection Timing Related - AutoCodes.com
P12B7 GMC Code - Cylinder 3 Injection Timing Related
What does this mean?

What are the Possible Causes of the DTC P12B7 GMC?

  • Contaminated or improper fuel quality
  • Worn base engine components or differences in cylinder compression
  • Faulty Fuel Injector
  • Fuel Injector harness is open or shorted
  • Fuel Injector circuit poor electrical connection

How to Fix the DTC P12B7 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P12B7 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 P12B7 GMC code?

Need more information on how to fix the P12B7 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P12B7 GMC 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 P12B7 GMC Code

1. What are common symptoms of OBDII code P12B7 GMC (Cylinder 3 Injection Timing Related)?

- Common symptoms include rough idling, reduced engine performance, misfires, and potential engine stalling.

2. What are the possible causes of OBDII code P12B7 GMC?

- Possible causes include a faulty fuel injector, wiring issues, ECM problems, or issues with the fuel injection timing system.

3. How can I diagnose the issue related to OBDII code P12B7 GMC?

- Diagnosing the issue typically involves using a scan tool to check for the specific code, inspecting the fuel injector in cylinder 3, and testing the wiring and connections related to the fuel injection system.

4. How can I repair OBDII code P12B7 GMC?

- Repair options include replacing the faulty fuel injector in cylinder 3, repairing any damaged wiring or connectors, or addressing any ECM issues that may be causing the problem.

5. Can I drive my vehicle with OBDII code P12B7 GMC?

- It is not recommended to drive the vehicle with this code present, as it can lead to further engine damage and potential safety hazards.

6. How much does it typically cost to repair OBDII code P12B7 GMC?

- The cost of repair can vary depending on the exact cause of the issue, but it may range from $200 to $600, including parts and labor.

7. Are there any preventive maintenance tips to avoid OBDII code P12B7 GMC?

- Regularly servicing your vehicle, using high-quality fuel, and keeping up with fuel system maintenance can help prevent issues that may trigger this code.

8. Can a DIY enthusiast repair OBDII code P12B7 GMC?

- While some aspects of diagnosing and repairing this code can be done by experienced DIY enthusiasts, it is recommended to consult a professional mechanic for proper diagnosis and repair.

9. How urgent is it to address OBDII code P12B7 GMC?

- It is important to address this code promptly to prevent further engine damage and ensure the vehicle operates safely and efficiently.

10. Will resetting the OBDII system clear the P12B7 GMC code?

- Resetting the system may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear.

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