Engine code
P0122: Throttle position signal too low
How much to fix P0122? Typically $290–$900.
How this range is built
| Part of the job | Low | High |
|---|---|---|
| Parts | $180 | $600 |
| Labor: 1 to 1.8 hours × $110 to $150 an hour | $110 | $270 |
| Fees: shop supplies, disposal, diagnostics | $0 | $25 |
| Total, rounded | $290 | $900 |
The hourly rate is the BLS Occupational Employment and Wage Statistics, May 2025 average pay for this trade in the US, $27.13 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, throttle body replacement. Which repair your car needs depends on a proper diagnosis.
The throttle position sensor is sending a very low voltage, as if the throttle is not being read at all. That usually means the sensor has failed, a wire has broken or lost power, or the plug is loose. The computer then limits power because it cannot see the throttle.
- Safe to drive?
- Short trips only
- Most common cause
- Failed throttle position sensor
Short drives only; expect weak response or limp mode, and stop if the car stalls.
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What you may notice
- Weak acceleration
- Stalling
- Reduced power mode
- Rough idle
Common causes, most likely first
- Failed throttle position sensor
- Broken wire or loose plug
- Failing throttle body assembly
- Poor ground
- Computer fault (rare)
Check this first
Check the throttle body plug for looseness, green corrosion or bent pins, and look at the wires leading to it for cracks. A plug that was recently removed for cleaning may not have clicked back in fully.
Other repairs that sometimes fix P0122
| Repair | Typical range, US |
|---|---|
| Throttle body cleaning | $75 to $180 |
| Diagnostic scan (check engine light) | $55 to $250 |
| CAN bus wiring repair | $170 to $1,125 |
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. Many states 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).
P0122 questions
Can I replace just the sensor?
On most modern cars, the sensor is built into the throttle body, so the whole unit is replaced. Parts for some older cars are sold separately, so ask your shop what applies to yours.
Why does my car feel slow?
The computer holds power back when it cannot read the throttle, so the car responds weakly or hesitates. This is a safety setting, and normal response returns once the sensor reads properly again.
Do I need a relearn after the repair?
Often yes. Many cars need a quick relearn with a scan tool so the computer learns the closed position and sets a smooth idle. Ask the shop to include it in the price of the repair.
How much does it cost to fix P0122?
The most common fix, throttle body replacement, has a typical range of $290 to $900 across the US. It is an estimate built from parts prices and local labor wages, not a quote. Your car and shop change it.
Typical range in 10 metro areas
Only the labor rate changes between cities. Same parts, same hours.
| Area | Typical range, estimate |
|---|---|
| Boston area, Massachusetts | $300 to $940 |
| New York City area | $300 to $930 |
| Los Angeles area, California | $300 to $940 |
| Chicago area, Illinois | $290 to $910 |
| Houston area, Texas | $280 to $890 |
| Dallas-Fort Worth area, Texas | $280 to $890 |
| Phoenix area, Arizona | $290 to $900 |
| Atlanta area, Georgia | $290 to $910 |
| Miami area, Florida | $280 to $900 |
| Seattle area, Washington | $300 to $940 |
Related codes
- P0121: Throttle position reading doesn't match
- P2135: Throttle position sensors disagree
- P0507: Engine idle higher than expected
- P0505: Idle control system problem
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.