EngineLightCodes
Powertrain code

P0135 O2 Sensor Heater Circuit Bank 1 Sensor 1

Severity
Fix soon
Typical repair cost
$10–$330
Do it yourself
Possible, easy
Shop time
0.2–1.5 hours

The upstream oxygen sensor on bank 1 (sensor 1) has an electric heater so that it reaches its working temperature of about 300 °C (572 °F) soon after a cold start.

How the engine computer detects it

The control module switches the heater on the ground side and checks driver voltage and heater current: GM fails it outside 0.3–2.5 A (or 3.1 A) and calls it 'heater performance', Ford outside roughly 0.22–0.465 A minimum to 3 A, Saab Trionic outside 0.5–2.3 A for 5 s. Manufacturers split heater faults differently between P0030–P0032, P0053 and P0135. With the heater dead, closed-loop control starts late after a cold start. If P0135 and P0141 appear together, check the shared fuse.

Written from public technical sources and not yet checked by a mechanic. How we write these pages

Symptoms

  • Check engine light on
  • Longer cold-start phase without mixture control, more fuel and emissions
  • Follow-up codes P0133/P0134 possible (cold sensor)

Common causes

  1. Heater element of the sensor burnt out (sensor must be replaced) Most likely
  2. Fuse or relay of the heater supply faulty Possible
  3. Heater wiring or connector open, corroded or shorted Possible
  4. Unsuitable replacement sensor (different heater resistance) Less likely
  5. Heater driver in the control module faulty Less likely

How to diagnose P0135

  1. Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
  2. Inspect the parts involved: oxygen sensor heater bank1 sensor1, oxygen sensor heater circuit, fuses.
  3. Work through the causes above from most to least likely, cheapest checks first.
  4. Clear the code and drive a full drive cycle to confirm the repair held.

Vehicles that report P0135 most

VehicleYearsReportsMedian miles
Chevrolet Volt2016–20184—

Counts of owner complaints to the NHTSA that mention P0135 (10 in total), not failure rates: popular models get more complaints simply because more of them are on the road. Models with fewer than 3 complaints are left out.

Reading the code

P
Powertrain
0
Generic (SAE) code
1
Fuel and air metering
35
Specific fault

Questions drivers ask

Can I drive with code P0135?

Usually yes for a short time, if the car drives normally, the temperature gauge reads normal and the check engine light is steady. If the light flashes, the engine loses power or overheats, or other warning lights come on, pull over and have it checked.

Will my car pass an emissions inspection with P0135?

Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.

Will P0135 clear by itself?

The light can go off after several drive cycles without the fault, but the code returns if the cause is still there. After a repair, the readiness monitors need a full drive cycle before an inspection.

Can I fix P0135 myself?

Often yes, with an OBD-II scanner and basic tools. Difficulty: easy. Start with the cheapest checks before replacing expensive parts.

Often reported together

Codes that owners mention in the same NHTSA complaints as P0135. They can point to a shared cause, so it's worth checking them together.

This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.