Category: Powertrain → Fuel System
Common on: All OBD-II gasoline and diesel engines (Duramax, Cummins, Power Stroke, etc.)
What it means (plain English)
The ECM/PCM has detected a problem in the injector control circuit. This usually means the injector driver isn’t seeing the expected voltage or resistance (open, short, or fault in the wiring or injector coil). It doesn’t point to low or high fuel pressure, but rather to an electrical issue with injector control. (obd-codes.com)
Symptoms you’ll notice
- MIL (Check Engine Light) on (repairpal.com)
- Misfire(s), rough running, poor idle
- Loss of power, hesitation, or stalling (yourmechanic.com)
- Poor fuel economy
- In some cases, no-start if multiple injectors affected
- May be intermittent (wiring/connectors making and breaking contact)
Priority level
High. Because it directly affects injector firing, it can cause misfires, driveability issues, and in diesels may lead to raw fuel entry and aftertreatment problems if ignored.
Common causes
- Faulty fuel injector (internal open circuit in coil winding) (obd-codes.com)
- Wiring harness issues (open, short, chafed, corroded) between ECM and injector
- Loose / corroded connector at injector or ECM (yourmechanic.com)
- ECM/PCM injector driver failure (less common)
- Poor electrical grounds
- Aftermarket modifications (tuning boxes, harness extensions) introducing resistance or opens
How pros diagnose it (step-by-step)
- Scan tool / freeze-frame
- Confirm P0200 and note load/RPM when set.
- Check for companion misfire codes (P0300-P030X).
- Cylinder balance test
- See which injector/cylinder is underperforming.
- Visual inspection
- Look for harness chafing, melted wiring, loose pins at connectors.
- Resistance test on injector(s)
- Unplug injector and measure resistance across coil terminals (compare to spec, typically a few ohms).
- Noid light / injector driver test
- Plug in a noid light or test lamp to injector connector; crank/run engine to see if ECM is pulsing. (obd-codes.com)
- Voltage check
- Verify 12 V supply at injector with key on.
- Verify ground pulsing from ECM during cranking/operation.
- Wiring continuity / wiggle test
- Continuity between ECM pin and injector connector.
- Wiggle harness while monitoring continuity to catch intermittent opens.
- Substitute injector (if possible)
- Swap with another cylinder to see if code follows the injector.
- Check ECM driver
- If injector and wiring test good, suspect ECM internal driver fault.
Likely fixes
- Replace faulty injector
- Repair or replace damaged wiring harness
- Clean / repair corroded connector pins
- Replace or repair ECM if injector driver is bad (rare but possible)
- Clear code and road test under varying load conditions
Related / companion codes
- P0201–P0208: specific injector circuit faults by cylinder
- P0300–P030X: misfire codes
- Fuel trim codes (P0171/P0172) if mixture imbalance occurs
Tech notes / platform tips
- Duramax & Cummins diesels: injector harness rub-through near valve covers is common → intermittent opens causing P0200.
- Ford Power Stroke: often triggered by injector wiring harness connectors overheating or vibrating loose.
- Gasoline DI systems: P0200 may appear with P0191/P0193 (fuel rail sensor codes) if both electrical and pressure control issues are present.