What it means
Throttle/fuel inhibit B line stuck high. 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
Throttle/fuel inhibit B is a control line used by the vehicle to allow or prevent engine fueling or throttle operation. The control module monitors its electrical state and sets P218E when it detects a high state, which can result from the line contacting battery positive or another power source.
Common causes
Most likely first.
- Short to B+
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check engine light on
- Engine may crank without starting or fail to start
- Reduced throttle response or engine power
- Security or transmission warning light may come on
How to diagnose it
- Review freeze-frame data and scan for related security, throttle, or transmission codes to identify when the B-line fault occurs.
- Inspect the throttle/fuel inhibit B wire and connectors for pinched insulation, chafing against a powered wire, corrosion, or terminals pushed back in the connector.
- With the code active, gently move the B-line harness while monitoring scan data or circuit state for a change.
- Use the vehicle wiring diagram to identify the B line, then test whether it is unintentionally connected to battery positive or another power feed.
- If the circuit wiring and terminals check out, test the connected components or modules using the manufacturer's diagnostic procedure.
Common fixes
- Repair a pinched or chafed B-line wire contacting a power source.
- Clean or repair corroded or loose connector terminals in the inhibit B circuit.
- Repair the short to battery positive in the B-line wiring.
- Replace a connected component or module only if testing confirms it is causing the high circuit state.
Can I keep driving?
If the engine runs normally, drive only as needed and be prepared for reduced throttle response or a no-start. Avoid a long trip until the circuit is checked, especially if the engine is already cranking without starting or losing power.
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.