Injector Circuit Low - Cylinder 6
The P0278 code means the vehicle's onboard diagnostic system has detected: Injector Circuit Low - Cylinder 6. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $150 - $600 (parts and labor)
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Common Symptoms
- Check Engine Light illuminated
- Cylinder 6 misfire
- Engine runs rough at idle
- Possible fuel smell from rich condition
Probable Causes (Ranked by Likelihood)
- Short to ground in cylinder 6 injector wiring Very High
- Internally shorted cylinder 6 injector High
- Corroded injector connector Moderate
- PCM driver stuck on Low
Step-by-Step Diagnostic Procedure
-
Measure cylinder 6 injector resistance. Below 10 ohms (port) or below 0.5 ohms (GDI) suggests internal short.
-
Disconnect injector and check wiring for short to ground.
-
Inspect injector connector for fuel contamination causing a conductive path.
-
Compare resistance to other injectors. All should be within 0.5 ohms of each other.
Frequently Asked Questions
What does circuit low mean for an injector?
Circuit low means the PCM detects more current flow than expected, typically from a short to ground in the wiring or an internally shorted injector.
Can a shorted injector cause flooding?
Yes, if the injector is shorted in a way that keeps it open, raw fuel will continuously enter the cylinder, causing flooding, rough running, and possible catalytic converter damage.
How do I check for a wiring short?
Disconnect the injector, then use a multimeter to check for continuity between each wire and engine ground. Any continuity indicates a short.
Sources
This page is built from documented references. Verify against your own service info before repair work.
P0278 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
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