What it means
The supply voltage feeding injector group D has dropped below the lower limit. The injectors in this group lose drive voltage and may stop firing, so the cylinders they serve run lean or cut out. Causes: a blown fuse, a failed injector supply relay, a voltage drop in the supply harness, or a poor ground or connector on the group-D supply.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Injector group D uses a shared power supply, while the engine control module switches each injector to control fuel delivery. This code sets when the module detects group D supply voltage below its expected lower limit, which can make those injectors operate intermittently or stop firing.
Common causes
Most likely first.
- Open or high-resistance supply wiring
- Blown fuse or failed supply relay
- Connector fault
Symptoms
- Check engine light on
- Misfire or rough idle on the affected cylinder
- Increased fuel consumption
- Possible fuel smell or smoke from exhaust
How to diagnose it
- Record freeze-frame data and check live misfire counts to see when group D voltage falls and which cylinders are affected.
- Inspect the group D fuse, relay, connectors, and harness for a blown fuse, loose or corroded pins, or damaged wiring.
- Measure voltage at the group D supply while the circuit is active and compare it with the manufacturer's specification.
- Check voltage drop across the group D wiring and connections under load to find a high-resistance point.
- If the wiring and connectors pass, test the group D supply relay and its control circuit using the vehicle's service information.
Common fixes
- Clean and secure a loose or corroded group D supply connector.
- Repair high-resistance or damaged group D supply wiring.
- Replace a blown fuse after finding and correcting the cause.
- Replace a failed injector supply relay.
Can I keep driving?
Avoid driving if the engine is misfiring severely or running roughly, because unburned fuel can damage the catalytic converter. If it runs smoothly, limit driving and arrange prompt diagnosis of the group D supply.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.