Injector 5 Output Circuit
Table of contents
P1235 GMC Possible Causes
- Faulty Fuel Injector 5
- Fuel Injector 5 harness is open or shorted
- Fuel Injector 5 circuit poor electrical connection
- Faulty Fuel Injection Control Module (FICM)
- Faulty Engine Control Module (ECM)
How do I fix code P1235 GMC?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Tech Notes
- 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
Cost of diagnosing the P1235 GMC code
The cost of diagnosing the P1235 GMC code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Engine Misfire
- Rough Running
P1235 GMC Description
The Engine Control Module (ECM) enables the appropriate fuel injector on the compression stroke for each cylinder. The ECM controls the Fuel Injection Control Module (FICM) by grounding the control circuit via a solid state device called a driver. The ECM monitors the state of the driver. If the ECM detects an incorrect voltage for the commanded state of an injector driver, Diagnostic Trouble Code (DTC) P1223, P1226, P1229, P1232, P1235, P1238, P1241, or P1244 will set.