Engine-CodesGMC – P1235 GMC

P1235 GMC Code - Injector 5 Output Circuit

Quick Answer

The P1235 GMC code indicates a problem with the injector 5 output circuit in the vehicle's engine control module (ECM). Common causes include Faulty wiring or connectors, Short circuit in the injector 5 output circuit, Open circuit in the injector 5 output circuit. 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
P1235 GMC indicates Injector 5 Output Circuit.
Common causes
Common causes include Faulty wiring or connectors, Short circuit in the injector 5 output circuit, Open circuit in the injector 5 output circuit.
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.
Table of contents Created and updated by William Orellana on Sep 10, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code P1235 GMC Description

The P1235 GMC code indicates a problem with the injector 5 output circuit in the vehicle's engine control module (ECM). The fuel injector is responsible for delivering fuel into the combustion chamber of the engine at the precise time and in the correct amount. When this code is triggered, it means that there is an issue with the electrical circuit that controls the operation of injector 5.

OBDII Code P1235 GMC - Injector 5 Output Circuit
P1235 GMC Code - Injector 5 Output Circuit

Common Causes of P1235 GMC

  1. Faulty wiring or connectors
  2. Short circuit in the injector 5 output circuit
  3. Open circuit in the injector 5 output circuit
  4. Corrosion in the connections
  5. Faulty injector or ECM

Symptoms of P1235 GMC

  1. Engine misfires
  2. Loss of power
  3. Rough idling
  4. Poor fuel efficiency
  5. Engine stalling or failing to start

How to Fix P1235 GMC

  1. Diagnose the issue by using a scan tool to identify the specific cause of the problem.
  2. Inspect the wiring and connectors for any signs of damage, corrosion, or loose connections.
  3. Test the injector 5 output circuit for continuity and voltage to determine if it is functioning properly.
  4. Replace any faulty wiring, connectors, or the injector itself if necessary.
  5. Clear the trouble codes from the ECM and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P1235 GMC

The typical repair costs for addressing a P1235 GMC code can vary depending on the exact cause of the issue and the specific vehicle. On average, the parts and labor for this repair could range from $200 to $500. However, it's important to note that diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. It's recommended to check with local shops for a more accurate estimate.

Tech Notes for P1235 GMC

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 P1235

Need more information about the P1235 GMC code?

Need more information on how to fix the P1235 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1235 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 P1235 GMC Code

No Frequently Asked Questions about P1235 GMC Code found.

Discuss the causes and fixes for P1235 GMC OBDII Code

Code P1235 GMC comments

No comments found for this page.