P2128 code meaning
Throttle/Pedal Position Sensor/Switch E Circuit High
Powertrain system Generic code P21xx codes Check engine light
What P2128 means
P2128 sets when pedal track E reads above its upper limit, typically from an open sensor ground, a short to 5 V or a broken track. Where E is a half-scale signal the limit lies far below the supply: GM's 2006 tables flag sensor 2 above 2.295 V and the 2014 VW Passat above 2.43 V. Pedals with two full-scale tracks use about 4.75 V (Ford, GM 2007, 19 of 39 counts) or 4.824 V for 0.2 s (GM's Bosch-based 2012 ECM). Since both tracks often share one ground, an open ground can set P2128 together with P2123. With E rejected the ECU steers on track D only and limits output; Ford's 2020-2023 summary lights MIL and wrench lamp. P2127 is the low fault on E, P2123 the high fault on D, P2138 the D/E comparison.
P2128 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2128
- Engine warning lamp and reduced power message
- Weak acceleration even with the pedal fully pressed
- Often stored together with P2123 if the ground is open
Common causes of P2128
- Most likelyOpen or high-resistance ground of the pedal sensor
- PossibleTrack E signal shorted to the 5 V reference
- PossibleBroken track or solder joint inside the pedal sensor
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Accelerator pedal position sensorPedal sensor wiringECM
What each part of P2128 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. |
| 28 | The exact fault in that area. |
What to do next
- Note P2128 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 P2128
What does P2128 mean?
P2128 means "Throttle/Pedal Position Sensor/Switch E Circuit High". P2128 sets when pedal track E reads above its upper limit, typically from an open sensor ground, a short to 5 V or a broken track. It is a generic code, so it means the same on every make.
Is it safe to drive with P2128?
Drive gently and only to a workshop. With P2128 the car can go into limp mode (reduced power) to protect itself.
Will P2128 fail an emissions test?
Yes, it can. P2128 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 P2128 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2128 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.