Ground Fault Detected in Fuel Injector Circuit (GM)
What does P1215 mean?
The P1215 code means the vehicle's onboard diagnostic system has detected: Ground Fault Detected in Fuel Injector Circuit (GM). This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Multiple cylinder misfires
- Rough idle and stalling
- Reduced engine power
- Engine may not restart after stalling
Probable Causes (Ranked by Likelihood)
- Short to ground in fuel injector wiring harness Very High
- Water intrusion in injector connector High
- Internally shorted fuel injector Moderate
- Damaged wiring harness from heat or chafing Moderate
- PCM internal ground fault Low
Step-by-Step Diagnostic Procedure
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Disconnect all injectors and test each for short to ground
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Reconnect one injector at a time to isolate the faulting circuit
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Inspect the entire injector wiring harness for chafing, bare wires, or water damage
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Check injector connectors for moisture intrusion
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Test each injector resistance to find the internally shorted unit
Frequently Asked Questions
What is a ground fault in the injector circuit?
A ground fault means an injector control wire is making contact with the vehicle ground (chassis or engine block) when it should not be. This causes the PCM injector driver to see unexpected current flow, which can affect multiple cylinders.
Can water cause a ground fault?
Yes. Water entering an injector connector creates a path to ground. This is especially common after pressure washing the engine bay or driving through deep water. Dry all connectors thoroughly and apply dielectric grease.
Why does P1215 affect multiple cylinders?
If the ground fault is in a shared portion of the wiring harness (before the harness branches to individual injectors), it can affect the entire injector system. This is why the code refers to the injector circuit in general rather than a specific cylinder.