P2166 code meaning
Throttle/Pedal Position Sensor D Maximum Stop Performance
Powertrain system Generic code P21xx codes Check engine light
What P2166 means
P2166 refers to position signal D, which on Ford designs is the first track of the accelerator pedal. The code means the reading with the pedal pressed all the way does not match the calibrated maximum, for instance because the pedal never reaches its stop or the track is worn at the far end. No manufacturer documents P2166 publicly; it applies the logic of the A version P2163 and of the open-stop learning in a Visteon patent to the pedal. A thick floor mat, a bent pedal arm or a worn pedal module are typical causes. The engine computer may then cap the torque request, so the car feels as if it never reaches full power. P2115 covers the rest position of D, P2120-P2124 its circuit, and P2138 the D/E correlation.
P2166 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyEasy, DIY possible
- Typical labor0.2 to 1 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2166
- Engine warning lamp on
- No kickdown or no full power with the pedal floored
- Possible limp mode
Common causes of P2166
- Most likelyFloor mat or object keeps the pedal from its stop
- PossiblePedal sensor track D worn at full travel
- Less likelyBent pedal arm or damaged pedal bracket
- Less likelyCorroded pedal connector shifting signal D
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Accelerator pedal position sensorThrottle position sensor
What each part of P2166 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. |
| 66 | The exact fault in that area. |
What to do next
- Note P2166 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 P2166
What does P2166 mean?
P2166 means "Throttle/Pedal Position Sensor D Maximum Stop Performance". P2166 refers to position signal D, which on Ford designs is the first track of the accelerator pedal. It is a generic code, so it means the same on every make.
Is it safe to drive with P2166?
Drive gently and only to a workshop. With P2166 the car can go into limp mode (reduced power) to protect itself.
Will P2166 fail an emissions test?
Yes, it can. P2166 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 P2166 to fix?
Difficulty: easy. A typical repair takes 0.2 to 1 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2166 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.