Engine code
P2122: Accelerator pedal sensor D signal too low
How this range is built
| Part of the job | Low | High |
|---|---|---|
| Parts | $0 | $0 |
| Labor: 0.5 to 1.5 hours × $125 to $175 an hour | $63 | $263 |
| Fees: shop supplies, disposal, diagnostics | $0 | $25 |
| Total, rounded | $60 | $290 |
The hourly rate is the BLS Occupational Employment and Wage Statistics, May 2025 average pay for this trade in Boston, $31.54 an hour, times 4 to 5.5 to cover what a shop bills (overhead, tools, insurance, profit). Parts are a band from budget aftermarket to the manufacturer part. Full method.
Not a repair shop, estimates only. Typical range, estimate. Not a quote. Your car, parts and shop change the number.
This is the range for the most common fix, diagnostic scan (check engine light). Which repair your car needs depends on a proper diagnosis.
The gas pedal has more than one sensor so the computer can cross-check how far it is pressed. Sensor D is sending a very low signal, which suggests a failed sensor, a broken wire or a lost power supply. The computer limits engine power when it cannot trust the pedal.
- Safe to drive?
- No, get it looked at first
- Most common cause
- Failed pedal assembly
The car may go into reduced power mode. Do not drive in traffic until fixed.
What you may notice
- Reduced power or limp mode
- Slow or no response to pedal
- Idle stuck high
- Check-engine light
Common causes, most likely first
- Failed pedal assembly
- Wiring or connector fault at the pedal
- Sensor reference voltage fault
- Computer fault
Check this first
Check the pedal connector under the dash for a loose fit, then have a shop watch the live pedal values on a scan tool as you slowly press. A jump or drop to zero shows an intermittent fault.
Other repairs that sometimes fix P2122
| Repair | Typical range, Boston |
|---|---|
| Throttle body replacement | $300 to $940 |
| CAN bus wiring repair | $190 to $1,275 |
| ECU / engine control module replacement | $430 to $2,350 |
Before you pay
- Ask the shop what test showed this part is the cause, not just that the code appeared.
- Ask for parts and labor listed separately, and for the hours.
- Ask for a written OK before any extra work. Massachusetts rules require written authorization before repairs.
Got a quote already? Check it against the range. Want to see if your car has a recall tied to this problem? Check recalls by VIN.
Need to read a code yourself? OBD-II scanners on eBay (affiliate link, disclosure).
P2122 questions
Is the pedal replaced as a unit?
Usually yes, because the sensors are built into the pedal assembly. Parts for some cars are matched to the computer, so use the right one, and ask whether any programming is needed.
Why does it limit power?
The computer will not trust a pedal it cannot cross-check. Limiting power is a safety design that prevents unexpected acceleration, even though it can feel frustrating on the road.
Is it safe?
Not in traffic, since power may change unexpectedly. If you must drive, keep trips short, avoid highways and leave extra room, and get the pedal and wiring checked soon.
How much does it cost to fix P2122?
The most common fix, diagnostic scan (check engine light), has a typical range of $60 to $290 in Boston. It is an estimate built from parts prices and local labor wages, not a quote. Your car and shop change it.
More engine codes
Code meaning written in our own words. Some codes mean different things on different makes, so check your scan tool or manual. Not a repair shop, estimates only.