P218E code meaning
Throttle/Fuel Inhibit B Circuit High
Powertrain system Generic code P21xx codes Check engine light
What P218E means
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.
P218E at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P218E
- Check engine lamp on the following drive
- Possible power reduction
Common causes of P218E
- Most likelyInhibit B wire shorted to a battery-fed circuit
- PossibleVoltage fed back through a faulty module after ignition off
- Less likelyRelay contacts welded, keeping the line energised
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Throttle fuel inhibitWiring harness
What each part of P218E means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 1 | Area: fuel and air metering. |
| 8E | The exact fault in that area. |
What to do next
- Note P218E and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P218E
What does P218E mean?
P218E means "Throttle/Fuel Inhibit B Circuit High". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P218E?
Drive gently and only to a workshop. With P218E the car can go into limp mode (reduced power) to protect itself.
Will P218E fail an emissions test?
Yes, it can. P218E is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P218E to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P218E clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.