Emissions code
P0135: Oxygen sensor heater fault (bank 1, before converter)
How much to fix P0135? Typically $100–$350.
How this range is built
| Part of the job | Low | High |
|---|---|---|
| Parts | $40 | $180 |
| Labor: 0.6 to 1 hours × $110 to $150 an hour | $66 | $150 |
| Fees: shop supplies, disposal, diagnostics | $0 | $15 |
| Total, rounded | $100 | $350 |
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, oxygen sensor replacement (one sensor). Which repair your car needs depends on a proper diagnosis.
The oxygen sensor before the catalytic converter has a small heater inside it that warms it up quickly after a cold start. The computer measured the heater's circuit and found it open or out of range. With the heater off, the sensor takes longer to work and the engine runs less cleanly at first.
- Safe to drive?
- Usually yes, for now
- Most common cause
- Failed sensor heater
Safe to drive.
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What you may notice
- Check-engine light on
- Slightly worse fuel economy
- Rough or uneven idle on cold starts
Common causes, most likely first
- Failed sensor heater
- Wiring fault
- Blown fuse
- Corroded plug
- Computer fault
Check this first
Look for a blown heater fuse in the fuse box and make sure the sensor plug is clean and clipped in. If both are fine, a new sensor is the typical repair, and a shop can check the heater resistance to confirm.
Other repairs that sometimes fix P0135
| Repair | Typical range, US |
|---|---|
| Diagnostic scan (check engine light) | $55 to $250 |
| Vacuum leak repair | $90 to $460 |
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).
P0135 questions
Is it a heater or the whole sensor?
The heater is built into the sensor, so the whole sensor gets replaced. Do not try to repair only the heater, because the part is sold as a single unit.
How long do they last?
Many last around 100,000 miles, though driving habits and the engine's condition change that. A sensor that fails sooner can be a sign of oil burning or coolant leaking into the exhaust.
Is this urgent?
Not urgent, since the car keeps running. But it will fail an emissions test while the light is on, and long-term it can hurt fuel economy, so plan to fix it within weeks.
How much does it cost to fix P0135?
The most common fix, oxygen sensor replacement (one sensor), has a typical range of $100 to $350 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 | $110 to $370 |
| New York City area | $110 to $360 |
| Los Angeles area, California | $110 to $370 |
| Chicago area, Illinois | $100 to $350 |
| Houston area, Texas | $100 to $340 |
| Dallas-Fort Worth area, Texas | $100 to $340 |
| Phoenix area, Arizona | $100 to $350 |
| Atlanta area, Georgia | $100 to $350 |
| Miami area, Florida | $100 to $350 |
| Seattle area, Washington | $110 to $370 |
Related codes
- P0030: Oxygen sensor heater circuit fault (bank 1, before converter)
- P0141: Oxygen sensor heater fault (bank 1, after converter)
- P0131: Oxygen sensor reads low voltage (bank 1, before converter)
- P0133: Oxygen sensor responding slowly (bank 1, before converter)
More emissions 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.