What it means
Ignition B control signal stuck low — short to ground. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The engine control module uses the Ignition B control signal circuit to command its assigned ignition coil or coil group, as defined by the vehicle wiring. P030E sets when the signal is below its expected range, which may indicate a short to ground, damaged insulation, or a poor connection in the Ignition B circuit.
Common causes
Most likely first.
- Short to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine light on or flashing
- Rough idle or engine misfire
- Hesitation or reduced power
- Engine may be difficult to start
How to diagnose it
- Check freeze-frame data and misfire counts to find out whether the cylinders served by Ignition B are affected when the code sets.
- Identify the Ignition B signal circuit from the vehicle wiring diagram and inspect its harness and connectors for chafing, moisture, corrosion, or loose terminals.
- Check the isolated Ignition B signal wire for a short to ground using the manufacturer's procedure.
- Measure the signal at the specified connector and operating condition, then compare it with the manufacturer's specification.
- If the wiring passes, test the Ignition B coil group and control-module output according to the manufacturer's procedure.
Common fixes
- Repair damaged Ignition B wire insulation or a short to ground.
- Clean or repair corroded Ignition B connectors.
- Restore terminal fit at a loose or pushed-back Ignition B connection.
- Replace a faulty coil in the Ignition B group if testing identifies it.
- Repair or replace the control module only if its output fails the manufacturer's tests.
Can I keep driving?
Stop when safe if the engine is misfiring badly or the check-engine light flashes, since an active misfire can overheat the catalytic converter. With a steady light and smooth running, keep driving limited and avoid hard acceleration until the Ignition B low signal is resolved.
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.