P1240
Injector Circuit Open Cylinder 4
Severity
⚠️ MediumCan you drive?
Do not drive — repair immediately
Approx. repair cost
$17–89 (est.)
Symptoms
- Unstable engine operation
- Misfire in cylinder 4
- Reduced engine power
- Increased fuel consumption
- Check Engine Light Is On
Causes
- Malfunction of the injector of the 4th cylinder
- Open or short circuit in wiring
- Poor contact in the injector connector
- Malfunction of the injector power supply relay
- Problems with the engine control unit
How to Fix
- Check the resistance of the injector of the 4th cylinder
- Inspect the wiring harness and connectors for damage.
- Check for voltage at the injector
- Test or replace the injector if necessary
- Check the operation of the injector relay