AutoCodes – GMC – P12C2 GMC

P12C2 GMC Code - Cylinder 8 Injection Timing Advance

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: P12C2 GMC indicates Cylinder 8 Injection Timing Advance.
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 3,855

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 Sep 11, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P12C2 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 P12C2 GMC - Cylinder 8 Injection Timing Advance - AutoCodes.com — P12C2 GMC Code - Cylinder 8 Injection Timing Advance

What does this mean?

What are the Possible Causes of the DTC P12C2 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 P12C2 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 P12C2 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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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 P12C2 GMC Code

1. What are the common symptoms of OBDII code P12C2 GMC (Cylinder 8 Injection Timing Advance)?

- Common symptoms include rough idling, decreased engine performance, and potentially increased fuel consumption.

2. What are some possible causes of OBDII code P12C2 GMC (Cylinder 8 Injection Timing Advance)?

- Possible causes may include a faulty fuel injector, issues with the fuel injection system, problems with the engine control module (ECM), or a malfunctioning timing system.

3. How can I diagnose the source of OBDII code P12C2 GMC (Cylinder 8 Injection Timing Advance)?

- Diagnosing this code typically involves conducting a thorough inspection of the fuel injection system, checking the fuel injector for proper operation, and using diagnostic tools to analyze the timing advance data.

4. Is it safe to continue driving with OBDII code P12C2 GMC (Cylinder 8 Injection Timing Advance) present?

- It is not recommended to continue driving with this code active, as it can lead to further engine damage and potential safety issues. It is best to address the underlying problem as soon as possible.

5. How can I repair OBDII code P12C2 GMC (Cylinder 8 Injection Timing Advance) myself?

- DIY repair options may include checking and cleaning the fuel injector, inspecting wiring connections, resetting the ECM, or replacing any faulty components identified during the diagnostic process.

6. Can OBDII code P12C2 GMC (Cylinder 8 Injection Timing Advance) be triggered by a loose gas cap?

- No, this specific code is related to the injection timing advance in Cylinder 8 and is not typically caused by a loose gas cap.

7. How much does it cost to repair OBDII code P12C2 GMC (Cylinder 8 Injection Timing Advance) at a professional auto repair shop?

- The cost of repairs can vary depending on the exact cause of the code, the labor rates of the repair shop, and the cost of any replacement parts needed. It is best to obtain quotes from different shops for an accurate estimate.

8. Can a bad spark plug cause OBDII code P12C2 GMC (Cylinder 8 Injection Timing Advance) to appear?

- While a bad spark plug can potentially affect engine performance, it is not a common cause of this specific code related to injection timing advance in Cylinder 8.

9. Will resetting the check engine light make OBDII code P12C2 GMC (Cylinder 8 Injection Timing Advance) go away?

- Resetting the check engine light without addressing the underlying issue will not make the code disappear permanently. It is important to diagnose and fix the root cause of the code to prevent it from reoccurring.

10. How long does it typically take to repair OBDII code P12C2 GMC (Cylinder 8 Injection Timing Advance)?

- The repair time can vary depending on the complexity of the issue, the availability of parts, and the experience of the technician. Some repairs may be completed within a few hours, while others may take longer if extensive troubleshooting is required.