Fuel Injector 4 Control Circuit Low
Low voltage detected in the control circuit for injector 4.
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What it means (plain English)
The computer is seeing less voltage than normal in the circuit that controls fuel injector 4. This means injector 4 may not be operating properly because it's not getting the right electrical signal.
What the computer is actually seeing
The ECM (Engine Control Module) reads the voltage from injector 4's control circuit. A normal voltage is typically around 12 volts when active. A drop below 5 volts indicates a problem.
What a healthy reading looks like
Expected voltage at the injector control circuit should be approximately 12 volts during operation. A reading below 5 volts is a concern.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the wiring and connectors for injector 4. Look for frayed wires, corrosion, or poor connections. Decision: If wiring is good, proceed. If not, repair or replace.
- 22. Measure the voltage at the connector of injector 4 with the engine running. You should see around 12 volts. Decision: If voltage is below 5 volts, note the reading and proceed. If above, injector may be faulty.
- 33. If voltage is low, check the ECM ground and power supply. Use a multimeter to ensure proper voltage to the ECM. Decision: If ground or power is compromised, repair. If good, go to step 4.
- 44. Swap injector 4 with another injector (e.g., injector 3). Clear codes and retest the system. Decision: If the code follows the injector, replace the injector. If the code stays, suspect ECM or wiring.
Common causes
- Bad wiring or connector to injector 4
- Faulty injector 4
- ECM programming issues
- Ground issues
- Short circuits in wiring harness
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It’s not recommended to drive long distances as it could lead to fuel delivery issues, affecting performance.
Will this code come back after clearing?
If the underlying issue is not fixed, yes, the code will likely return.
Why does it pair with other injector codes?
Multiple injector codes often indicate issues with the wiring or ECM affecting multiple injectors.
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