Fuel Injector 2 Short Circuit (GM)
What does P1225 mean?
The P1225 code means the vehicle's onboard diagnostic system has detected: Fuel Injector 2 Short Circuit (GM). This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Cylinder 2 misfire
- Rough idle
- Reduced power
- Possible fuel smell from exhaust
Probable Causes (Ranked by Likelihood)
- Internally shorted cylinder 2 fuel injector Very High
- Short in injector 2 wiring harness High
- Corroded injector connector causing low resistance path Moderate
- Wiring chafing against engine block Moderate
- PCM injector driver over-current detection Low
Step-by-Step Diagnostic Procedure
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Measure cylinder 2 injector resistance (low reading confirms short)
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Check wiring from the injector connector back to the PCM for shorts
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Inspect the injector connector for signs of overheating or corrosion
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Swap the injector with another cylinder to confirm it is the injector
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Check the wiring harness for rubbing against metal surfaces
Frequently Asked Questions
What does a short circuit mean for a fuel injector?
A short circuit means the injector coil has reduced resistance, causing it to draw more current than designed. This can cause the injector to stay open too long, flooding the cylinder, or it can damage the PCM driver circuit.
Can a shorted injector damage the PCM?
Yes, potentially. A severely shorted injector draws excessive current that can overheat and damage the PCM's injector driver transistor. Replace the injector promptly to prevent more expensive damage.
How do I measure injector resistance?
Disconnect the injector electrical connector. Set your multimeter to ohms and measure across the two injector pins. Compare the reading to GM specifications (typically 11-16 ohms for port injection). A reading significantly lower indicates a short.