P0204
Fuel Injector Circuit/Open - Cylinder 4
The injector circuit for cylinder 4 is not behaving the way the PCM expects. That can leave cylinder 4 underfueled or unfueled and create shaking, hesitation, and power loss.
- SEV
- 4/5
- DRIVE
- CAUTION
- DIY
- $20-$250
- SHOP
- $150-$700
Quick answer
AI-CITATION READYWhat it means
Can you drive with it?
Most common causes
- Faulty cylinder 4 fuel injector
- Damaged, loose, or corroded injector 4 connector or wiring
- Shorted or open injector control circuit for cylinder 4
Typical repair cost
DIY usually runs $20-$250. Typical shop repair lands around $150-$700, depending on the root cause.
01 / Definition
P0204 means the PCM detected an injector circuit problem affecting cylinder 4. The injector driver may see an open circuit, short, abnormal resistance, or a response that does not match what the PCM expects when it commands the injector on and off.
02 / Drive status
With caution. Driving may still be possible, but a cylinder 4 injector circuit fault can create harsh misfires and catalyst damage. Keep trips short until injector 4 wiring and operation are tested.
03 / Symptoms
- Check engine light
- Rough idle
- Cylinder 4 misfire
- Poor throttle response
- Fuel smell or rich exhaust
04 / Causes
| 1 | Faulty cylinder 4 fuel injector | high |
|---|---|---|
| 2 | Damaged, loose, or corroded injector 4 connector or wiring | high |
| 3 | Shorted or open injector control circuit for cylinder 4 | medium |
| 4 | PCM driver fault | medium |
05 / Diagnostic sequence
- 01Confirm P0204 and review any cylinder 4 misfire counters or companion codes.
- 02Inspect the injector 4 connector for corrosion, looseness, heat damage, or spread terminals.
- 03Check the harness between injector 4 and the main loom for rubbing or breakage.
- 04Measure injector resistance and compare it to the rest of the injector set.
- 05Verify injector pulse and feed voltage so you know whether the fault is in the injector, wiring, or PCM.
06 / Repairs
| 1 | Repair the injector 4 connector, harness damage, or poor grounds | $20-$150 |
|---|---|---|
| 2 | Replace the cylinder 4 injector if it fails resistance or swap testing | $50-$300 |
| 3 | Address PCM driver or power supply faults if injector command is missing | $150-$700 |
07 / Related codes
08 / FAQ
Can P0204 make the car shake at idle?
Yes. If cylinder 4 is not getting proper injector control, the engine can shake noticeably at idle and under load.
Does P0204 mean the injector is clogged?
Not necessarily. This code is mainly about the electrical circuit, though a failed injector can still be part of the problem.
What is the quickest check for P0204?
Start with the injector connector, wiring, and resistance test. Those checks often reveal whether the problem is the injector itself or the circuit.
09 / Source and method
- DATA BASIS
- OBD-II REFERENCE + OBD2.HELP
- METHOD
- STATIC VALIDATION
- SAFETY
- INFORMATIONAL
This page combines OBD-II diagnostic reference data with OBD2.help generated diagnostic guidance for code meaning, likely causes, and repair direction.
Publishing uses deterministic schema and build validation, plus manual spot checks on representative pages before release.
Safety-critical diagnosis and repairs should be confirmed with a qualified mechanic, especially when the vehicle is misfiring, overheating, or losing power.