AutoCodesGMC – P1236 GMC

P1236 GMC Code - Fuel Injector 5 Control Circuit Shorted

Quick Answer

The Engine Control Module (ECM) supplies voltage to each fuel injector on the injector positive voltage control circuits. Common causes include Faulty Fuel Injector 5, Fuel Injector 5 harness is open or shorted, Fuel Injector 5 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
P1236 GMC indicates Fuel Injector 5 Control Circuit Shorted.
Common causes
Common causes include Faulty Fuel Injector 5, Fuel Injector 5 harness is open or shorted, Fuel Injector 5 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 2,669
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Nov 10, 2020
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Code P1236 GMC Description

The Engine Control Module (ECM) supplies voltage to each fuel injector on the injector positive voltage control circuits. The ECM energizes each fuel injector by grounding the control circuit of that fuel injector. The ECM monitors the status of the injector positive voltage control circuits and the fuel injector control circuits. When a fuel injector circuit condition is detected by the ECM, the affected fuel injectors will be disabled and may disable the affected group of fuel injectors. The Diagnostic Trouble Code (DTC) will set when the ECM injector output driver detects an incorrect current on a fuel injector circuit.
OBDII Code P1236 GMC - Fuel Injector 5 Control Circuit Shorted - AutoCodes.com
P1236 GMC Code - Fuel Injector 5 Control Circuit Shorted

What are the Possible Causes of the DTC P1236 GMC?

  • Faulty Fuel Injector 5
  • Fuel Injector 5 harness is open or shorted
  • Fuel Injector 5 circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

How to Fix the DTC P1236 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 P1236 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 P1236 GMC code?

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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 P1236 GMC Code

1. What does the OBDII code P1236 mean on a GMC vehicle?

P1236 indicates a short circuit in the control circuit for fuel injector 5, which can prevent proper fuel delivery to the engine.

2. What are the symptoms of a P1236 code on a GMC?

Common symptoms include rough idling, misfires, decreased engine performance, poor fuel economy, and potential difficulty starting the vehicle.

3. What causes the P1236 code to appear?

The most common causes are damaged or shorted wiring to fuel injector 5, a faulty injector, or a malfunctioning engine control module (ECM).

4. Can a P1236 code cause engine damage if ignored?

Yes, prolonged operation with this code can lead to misfires, increased stress on engine components, and potential long-term damage.

5. How do I diagnose a P1236 code on my GMC?

Start by inspecting the wiring and connectors for fuel injector 5, test the injector for proper function, and use a multimeter to check for short circuits or continuity issues.

6. Can I drive my GMC with a P1236 code?

Driving with this code is not recommended as it can lead to poor performance, increased fuel consumption, and potential damage to the engine.

7. How do I fix the P1236 code on a GMC?

Repairs may include replacing or repairing damaged wiring, replacing the fuel injector, or reprogramming or replacing the ECM if it’s determined to be faulty.

8. How much does it cost to fix the P1236 code on a GMC?

Repair costs vary but typically range from $150 to $400, depending on whether it’s a wiring repair or injector replacement. ECM replacement can be more expensive.

9. Can a bad fuel injector cause the P1236 code?

Yes, a faulty fuel injector can trigger this code if it causes a short circuit or fails to communicate properly with the ECM.

10. What tools are needed to troubleshoot the P1236 code?

You’ll need an OBDII scanner, a multimeter, and potentially a wiring diagram for your GMC model to diagnose and repair the issue.

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