OBD-II code · Powertrain (generic, extended)

P218D Throttle/Fuel Inhibit B Circuit Low

Throttle/fuel inhibit B line stuck low. 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.

Is it safe to drive with P218D?

Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.

Common causes

  • Most likelyShort to ground
  • Less likelyConnector pins corroded - high contact resistance
  • Less likelyHarness chafing through insulation

Repair at a glance

Difficulty
Hard
DIY friendly
Best left to a mechanic
Typical labour
0.5–3 h
Emissions test
Likely to fail
Parts involved
Throttle Fuel Inhibit

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.