P1238 CHEVROLET, GMC: INJECTOR 6 OUTPUT CIRCUIT
POST UPDATED IN May, 2023
P1238 Code failures by brands
Description of DTC code P1238
Injectors are major components of the fuel delivery system. Their purpose is to deliver the fuel at the required pressure. With the use of injectors, carburetors are no longer necessary, considering that injectors offer a more precise fuel injection.
The modern fuel injection system is electronically controlled. In this type of system, an electromagnet is responsible for driving a spring, whose function is basically to give or cut the fuel delivery. The ECM (Engine Control Module) enables the corresponding fuel injector in the compression stroke for each cylinder. The ECM controls the FICM (Fuel Injection Control Module) by grounding the control circuit through a solid state device known as a controller.
The ECM continuously monitors the status of the controller. Should an incorrect voltage be found for the commanded state of the injector controller, a fault code will be set. In the case of the P1238 OBD2 code, it refers to injector number 6.
Symptoms of fault code P1238
- Check Engine lamp illuminated.
- Trouble starting the engine.
Causes of OBD2 P1238
P1238 OBDII diagnostic code is set for one of the following reasons:
- The number 6 fuel injector wiring may have been damaged.
- The number 6 injector may be faulty.
- The Fuel Injection Control Module (FICM) could be faulty.
- The ECM could be damaged.
Possible solutions of the DTC code P1238
Consider the following steps to troubleshoot DTC P1238 OBD2:
- Consult the Technical Service Bulletins.
- By means of an automotive scanner, you should check if there are other DTCs Take into account that, if only the P1238 code is set, the most probable cause is an open or short circuit in the injector. But if there are groups of 4 fuel injector control circuit DTCs set, suspect a short to ground. The cylinder groups are 2, 3, 5, 8 or 1, 4, 6, 7.
- Inspect the fuel injector circuit wiring and connections 6. Look for common deficiencies that could cause an open circuit and if such conditions are discovered, make corrections.
- If you determine that the fuel injector 6. is damaged, replace it.
