Engine code
P0505: Idle control system problem
How much to fix P0505? Typically $75–$180.
How this range is built
| Part of the job | Low | High |
|---|---|---|
| Parts | $0 | $15 |
| Labor: 0.7 to 1 hours × $110 to $150 an hour | $77 | $150 |
| Fees: shop supplies, disposal, diagnostics | $0 | $15 |
| Total, rounded | $75 | $180 |
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 cleaning. Which repair your car needs depends on a proper diagnosis.
The computer holds the engine at a steady idle by letting in a small, controlled amount of air. This time it could not keep the idle where it wanted, so the idle valve or throttle is not responding the way it expects. The engine may idle too fast, too slow, or hunt up and down.
- Safe to drive?
- Short trips only
- Most common cause
- Dirty throttle body or idle valve
Drive gently, but stalling at stoplights can be a safety issue.
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What you may notice
- Idle too high or too low
- Stalling at stops
- Rough idle
- Check-engine light
Common causes, most likely first
- Dirty throttle body or idle valve
- Vacuum leak
- Failing idle air control valve
- Carbon in intake
Check this first
Ask for a throttle body cleaning and a vacuum leak check first. Carbon around the throttle blade and a cracked hose are the two most common causes, and neither costs much to check.
Other repairs that sometimes fix P0505
| Repair | Typical range, US |
|---|---|
| Vacuum leak repair | $90 to $460 |
| Throttle body replacement | $290 to $900 |
| Diagnostic scan (check engine light) | $55 to $250 |
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).
P0505 questions
Why is my idle surging?
Dirt in the throttle or an air leak makes the idle hunt up and down. The computer keeps adding and cutting air to chase its target, and that cycle feels like surging.
Do I need a new throttle body?
Often cleaning is enough. Carbon buildup on the throttle blade and bore is usually the cause, and a cleaning and idle relearn costs far less than a new throttle body.
Does battery matter?
Disconnecting power can reset the idle memory in the computer, so a relearn may be needed after battery or throttle work. Ask the shop whether the price includes it.
How much does it cost to fix P0505?
The most common fix, throttle body cleaning, has a typical range of $75 to $180 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 | $85 to $210 |
| New York City area | $80 to $200 |
| Los Angeles area, California | $80 to $200 |
| Chicago area, Illinois | $80 to $190 |
| Houston area, Texas | $70 to $180 |
| Dallas-Fort Worth area, Texas | $70 to $180 |
| Phoenix area, Arizona | $75 to $180 |
| Atlanta area, Georgia | $80 to $190 |
| Miami area, Florida | $70 to $180 |
| Seattle area, Washington | $85 to $200 |
Related codes
- P0506: Idle speed lower than expected
- P0507: Engine idle higher than expected
- P0300: Random or multiple cylinder misfires
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.