P0203: Injector Circuit Malfunction - Cylinder 3
Can you still drive? Not recommended. A non-functioning injector causes a constant misfire that can damage the catalytic converter.
What Does P0203 Mean?
Code P0203 means the ECM has detected an electrical fault in the fuel injector circuit for cylinder 3. The injector may have failed open, shorted, or the wiring to it is damaged. Without proper injector operation, cylinder 3 cannot receive the correct amount of fuel, resulting in a misfire.
Need to read your codes?
An OBD-II scanner lets you read and clear diagnostic trouble codes from your vehicle's computer. Most scanners work with any car made after 1996.
Browse OBD-II Scanners on AmazonCommon Causes
- Failed fuel injector on cylinder 3
- Broken or shorted wiring to the injector
- Corroded injector connector pins
- Faulty ECM injector driver circuit
Symptoms
- Check engine light on
- Engine misfire on cylinder 3
- Rough idle
- Reduced engine power
- Possible exhaust smell of unburned fuel
Diagnostic Steps
- 1Read freeze frame data and check for misfire codes on cylinder 3
- 2Measure cylinder 3 injector resistance and compare to specifications
- 3Use a noid light to verify ECM is sending a signal to the injector
- 4Swap injector with another cylinder to isolate the fault
- 5Inspect wiring harness for chafing, breaks, or shorts
Recommended Parts & Tools
fuel injector
noid light test kit
Estimated Repair Cost
| Type | Estimated Cost |
|---|---|
| Total Repair Cost Range | $150 - $600 |
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Chat with AI About P0203Commonly Affected Vehicles
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Frequently Asked Questions
How much does it cost to replace a fuel injector?
A single fuel injector typically costs between $50 and $200 for the part. Labor adds another $100 to $300 depending on the vehicle and accessibility of the injector.
Should I replace all injectors if one fails?
It is not required, but if one injector has failed and the others have high mileage, replacing the full set ensures even fuel delivery and prevents repeat repairs.
Community Fix Reports
Community reports are user-submitted and not verified by Auto AI Buddy. Results may vary.
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