What it means
The primary control circuit of ignition coil G reads a voltage above the expected level — typically an open primary circuit or a short to battery voltage on the primary control wire. The ECU sees no normal current flow, coil G does not fire, and the cylinder misfires. Causes: an open or disconnected primary wire, an internal open in the coil, or a faulty ECU driver.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Coil G's primary control circuit carries the low-voltage current needed to charge the coil before it fires. This code means the control module detects voltage higher than expected, commonly because the circuit is open or its control wire is shorted to a power supply; coil G may then fail to fire its cylinder.
Common causes
Most likely first.
- Open circuit in primary winding or harness for coil G
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check-engine light
- Engine misfire or rough running
- Reduced power or hesitation
How to diagnose it
- Record freeze-frame data and check live misfire counts to see whether the coil G cylinder is affected.
- With the ignition off, inspect coil G's connector and harness for a disconnected plug, broken wire, corrosion, or wiring pinched near a power source.
- Check that coil G's connector is fully seated and its terminals are clean and secure.
- Use the wiring diagram to test the coil G primary control wire for an open circuit or short to supply, comparing results with the manufacturer's specification.
- If the wiring is intact, test coil G's primary winding and control driver using the manufacturer's procedure.
Common fixes
- Reconnect and secure a loose coil G connector.
- Repair an open or damaged coil G primary wire.
- Repair a control wire shorted to battery or another supply.
- Replace coil G if its primary winding is open.
- Repair the control driver only if testing confirms it is faulty.
Can I keep driving?
Keep trips short and avoid hard acceleration while the coil G cylinder may be misfiring. If the check-engine light flashes or the engine runs roughly, stop when safe because unburned fuel can overheat the catalytic converter.
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.