P0122: Throttle/Pedal Position Sensor A Circuit Low
Key takeaways
- P0122 means the throttle position sensor's signal voltage has dropped below the lowest value a working sensor can produce.
- It usually puts the car in reduced-power (limp) mode, which limits speed, so drive short trips only and stay off the highway.
- A bad connection, a chafed wire or a shorted 5-volt reference causes it more often than the sensor itself; wiring repair runs $100–$250.
- If the sensor is at fault on a drive-by-wire car, the fix is a new electronic throttle body at $300–$700.
- Chrysler, Dodge and Jeep bulletins for P0122 are mostly PCM software updates; Ford has bulletins for the Transit Connect 2.5L and Focus 2.0L.
What P0122 means
The throttle position sensor’s signal is lower than it should ever be, so the computer treats it as a broken circuit. Scanners call it “Throttle/Pedal Position Sensor/Switch A Circuit Low.” The sensor gets a 5-volt supply and a ground from the computer and sends back a voltage that rises as the throttle opens. Even with the throttle closed, a working sensor never reads near zero. When the signal drops below that floor, P0122 sets. That almost always means an open, a short to ground, or a lost reference, not a worn sensor track.
Is it safe to drive?
Short trips only. Most cars go into reduced-power (limp) mode with P0122: the throttle is held to a small opening and speed is limited. You can usually limp to a shop nearby. Don’t take it on the highway, because the car may not accelerate enough to merge or keep pace.
The symptom that changes the answer: the engine won’t rise above idle, surges on its own, or stalls. Then have it towed.
Causes, ranked
| Cause | How you confirm it | Typical cost (US independent shop, 2026) |
|---|---|---|
| Loose, corroded or damaged connector at the throttle body | Inspect pins and lock tab; reseat and clear the code | $100–$250 |
| Chafed wire shorting to ground or broken signal wire | Continuity and short-to-ground checks; signal drops when the harness is moved | $100–$250 |
| 5-volt reference pulled low by another sensor sharing it | Several sensor codes at once; the reference recovers when the other sensor is unplugged | $100–$250 plus that sensor |
| Failed sensor or electronic throttle body | Good 5 V and ground at the connector, but the signal is still low | $300–$700 (throttle body); older separate sensor $100–$250 |
| Software (Chrysler-group, some Ford) | Dealer checks for a PCM update | $100–$200, or free under warranty |
| Computer (ECM/PCM) | No 5 V reference out of the module with wiring proven good; rare | $800–$1,800 plus programming |
What to check first
- Read every stored code. Multiple sensor codes together point to a shared reference or ground, not one sensor.
- Unplug and inspect the throttle body connector. Look for corrosion, oil or coolant in the plug, and spread or pushed-back pins.
- Check the harness where it bends near the throttle body and where it rubs on brackets.
- Measure the 5-volt reference and ground at the connector with the key on before condemning the sensor.
- Clean the throttle body while it’s accessible and run the relearn after any repair.
- Ask about a software update on a Chrysler, Dodge or Jeep.
The bulletin pattern is clear. Chrysler-group bulletins (2016 Jeep Wrangler and Grand Cherokee, 2016 Dodge Charger and Challenger, 2013 Durango, 2015 Chrysler 300) are PCM reprogramming updates that list P0122 among other codes. Ford has drivability bulletins for the 2014–2016 Transit Connect 2.5L and the 2012–2014 Focus 2.0L, and Mazda one for the 2009–2010 Tribute.
What it costs
The cheap outcome is a reseated or cleaned connector, or a software update at $100–$200. The common outcome is a wiring or connector repair at $100–$250. The expensive outcome is a new electronic throttle body at $300–$700, or rarely a computer. Proving the wiring first is what keeps you out of the expensive column. If you want help reading the other codes on your scan, ask our AI mechanic.
Related codes
P0123 is the same circuit reading high and P0121 the range/performance version. P0222 is the second throttle sensor reading low; together with P0122 it points to a shared wire. P2135 often follows because the two sensors disagree. If pedal codes like P2122 show up too, suspect the shared 5-volt reference. For stalling, see car stalls while driving.
What owners report to NHTSA
17 complaints filed with NHTSA mention P0122, 10 of them since 2015, across 15 different models. The component owners most often filed it under: electrical system.
Manufacturer service bulletins that name P0122
25 technical service bulletins and manufacturer communications filed with NHTSA mention P0122, from 5 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:
- FORD TRANSIT CONNECT (2014, 2015, 2016), bulletin 10094582: SOME 2014-2016 TRANSIT CONNECT VEHICLES EQUIPPED WITH THE 2.5L ENGINE MAY EXHIBIT A CONSTANT OR INTERMITTENT ILLUMINATED MIL WITH VARIOUS DRIVABILITY ISSUES AND ONE OR MORE OF THE FOLLOWING DTCS: P0010, P0103, P0104, P01…
- JEEP WRANGLER (2016), bulletin 10121706: Flash: Powertrain Diagnostic And System Enhancements This bulletin involves reprogramming the Powertrain Control Module (PCM) with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL…
- DODGE CHARGER (2016), bulletin 10129030: Flash: Powertrain Diagnostic And System Improvements This bulletin involves reprogramming of the Powertrain Control Module (PCM) with the latest software. Customers may experience a Malfunction Indicator Lamp (MIL) illum…
- DODGE CHALLENGER (2016), bulletin 10135115: Flash: Powertrain Diagnostic And System Improvements This bulletin involves reprogramming of the Powertrain Control Module (PCM) with the latest software. Customers may experience a Malfunction Indicator Lamp (MIL) illum…
- JEEP GRAND CHEROKEE (2016), bulletin 10136529: Flash: Powertrain Diagnostic And System Enhancements This bulletin involves reprogramming the Powertrain Control Module (PCM) with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL…
- CHRYSLER 300 (2015), bulletin 10084055: "FLASH: DIAGNOSTIC AND SYSTEM IMPROVEMENTS THIS BULLETIN INVOLVES REPROGRAMMING OF THE POWERTRAIN CONTROL MODULE (PCM) WITH THE LATEST AVAILABLE SOFTWARE. CUSTOMERS MAY EXPERIENCE ONE OR MORE OF THE FOLLOWING SYMPTOMS AN…
Sources: NHTSA Office of Defects Investigation complaint database and manufacturer communications file, snapshots September 2026. A complaint or bulletin that mentions a code is a report about that vehicle, not a statement that the code has one cause.
Frequently asked questions
What is the most common cause of P0122?
A wiring problem: a loose or corroded connector at the throttle body, a wire rubbed through against a bracket, or the sensor's 5-volt supply being pulled down. The sensor itself is further down the list.
Can I drive with P0122?
For short, low-speed trips, usually. Most cars limit throttle and speed in limp mode, so avoid the highway. If the engine surges, stalls or won't rev, have it towed.
Will cleaning the throttle body fix P0122?
Rarely on its own, because P0122 is an electrical reading, not an airflow one. It's still worth cleaning while the throttle body connector is off, and a relearn is needed after any throttle body work.
Why do I have P0122 and P0222 at the same time?
Both throttle sensors reading low at once points to something they share: the connector, the 5-volt reference, or the ground. That's a wiring diagnosis before it's a parts purchase.