P218EThrottle/Fuel Inhibit B Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P218E says the inhibit B line carries more voltage than the controller allows, typically because it touches a battery-fed wire or the sending unit's output stage is stuck high. No manufacturer documents P218E publicly. On the A line, GM's 2005 table for the 3.5-litre V6 (L66) uses two limits for P2555: more than 10 V with the ignition on, or more than 4.5 V once the ignition is off, each judged over 4 seconds; the check runs after shutdown and the MIL lights on the next drive cycle. The lower limit with the ignition off shows that the line should be nearly dead when the system sleeps. California's OBD rule requires such range checks. Look for chafing against supply wires, a backfeed through a faulty module or a shorted relay. P218D is the low-side counterpart.
- What you may notice
- Check engine lamp on the following drive
- Possible power reduction
- Likely causes
- LikelyInhibit B wire shorted to a battery-fed circuit
- PossibleVoltage fed back through a faulty module after ignition off
- RareRelay contacts welded, keeping the line energised
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.