P0057 code: O2 Sensor Heater Control Circuit Low (Bank 2, Sensor 2)
P0057 means o2 Sensor Heater Control Circuit Low (Bank 2, Sensor 2). The code says where to look, not what failed — the fix depends on which cause your car actually has.
What P0057 means
Decoding the position first: Bank 2 is the cylinder bank without cylinder 1 (so this code lives on V6/V8/flat engines, not most inline-4s), and Sensor 2 is the downstream oxygen sensor mounted after that bank's catalytic converter. The sensor's built-in heater gets it to operating temperature within seconds of start-up so converter monitoring can begin early; the sensor itself has no significant role in fuel mixing. P0057 means the computer found voltage in that heater's control circuit lower than expected — the standard interpretations being a short to ground in the wiring or a heater element that has failed open. Real-world experience puts an internally failed sensor at the top of the cause list, with corroded underbody connectors and chafed or salt-damaged harness sections close behind, and the heater fuse as an occasional easy win. The check-engine light is typically the only thing a driver ever notices.
P0057 symptoms
- Check-engine light, usually the sole symptom
- No change in drivability or fuel economy
- Vehicle fails OBD emissions testing while the code is set
What it costs to fix P0057
Typical range: $125–$400 · about ~0.3–1.2 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Downstream oxygen (O2) sensor | $30–$200 | ~0.3–1.2 hrs |
| Wiring / connector repair | $10–$120 | ~0.5–1.5 hrs |
| Heater-circuit fuse | $1–$10 | ~0.1–0.3 hrs |
A straightforward job on most vehicles — the sensor is usually visible from underneath and the part is on the cheaper end. Costs climb mainly with rust-seized sensors, tight packaging around the converter, or a wiring fault that takes time to locate.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0057 for my exact vehicle →
How to fix P0057
Moderate — doable at home with common tools and patience
- Pin down the sensor before buying anything
Bank 2 is the cylinder bank without cylinder 1, so P0057 belongs to V and flat engines; Sensor 2 is the oxygen sensor mounted after that bank's catalytic converter. On dual exhausts it's on the Bank 2 pipe; where both sides join early, confirm the position in service information or the scan tool's sensors-present data. An inline engine showing P0057 is worth re-reading with another tool.
- Read every heater code and the freeze frame
P0037 alongside P0057 suggests the two rear heaters share a fuse, feed or ground splice; upstream heater codes as well point at the fuse or relay feeding all of them. P0057 alone keeps it to this sensor and its lead. The freeze frame usually shows it set shortly after start-up, when the engine computer first runs its heater circuit check.
- Decode 'low' using the wiring diagram
Find out which side of the heater the engine computer switches. On the common ground-switched design, the control wire should rest near battery voltage with the heater off, and an open element, a blown fuse, a broken feed or a wire grounded to the body all read low. Where the feed side is switched, low points mainly at an output wire shorted to ground.
- Measure pull-up voltage, then the element
With the sensor plugged in, key on and engine off, back-probe the control wire. Near battery voltage clears the element and feed. Near zero, unplug the sensor and ohm its heater terminals cold: open — the most common result — means a new sensor. A good element with battery voltage still present at the feed terminal means the fault is in the wiring, not the part.
- Hunt the ground under the floor
This plug sits in the spray zone, so check it for salt and water first — corrosion bridging a heater pin to ground can drag the circuit low by itself. Then, with the battery and the engine computer connector unplugged per the service manual, check the control wire to body ground while flexing the harness at clips, crossmembers and heat shields. Repair chafes with soldered, sealed splices.
- Fit the right sensor and prove the repair
Install a new Bank 2 Sensor 2 listed for the downstream position, anti-seize on the threads only, and re-clip the lead away from the pipe. Clear the code and check that the O2 heater and catalyst readiness monitors complete before an inspection. If a known-good sensor and clean wiring still set P0057, the computer's heater driver is the remaining suspect and needs dealer-level confirmation.
DIY or shop? P0057 is a good home-mechanic code: the sensor is behind the converter, runs cooler than the upstream ones and is usually easier to reach from below, and every test above needs only a multimeter, the wiring diagram and a safe way under the car. It turns into shop work if the grounded wire disappears into the body harness, if the sensor has rusted into the pipe badly enough to risk the threads, or if the wiring and a known-good sensor both check out — confirming a failed driver and programming a replacement computer takes dealer-level equipment.
Tools for the DIY steps: Scan tool with freeze frame and readiness data · Digital multimeter with back-probe pins · Wiring diagram for the heater circuit · Jack stands or ramps · O2 sensor socket · Dielectric grease
Not sure which step applies to your car? Get the likely cause for your exact vehicle before buying anything for P0057.
Start a case with P0057 and your car. Redline weighs these causes against what your car shows, and names the check that would settle it before you buy parts.
Can I drive with P0057?
Redline can’t determine from a symptom or code alone whether your car is safe to drive.
P0057: common questions
Where exactly is the sensor for P0057 on my car?
After the catalytic converter on the Bank 2 side — the cylinder bank that doesn't include cylinder 1. On a V-type engine each bank has its own exhaust path, so make sure you trace the correct one; buying or replacing the Bank 1 downstream sensor by mistake is a common and frustrating error.
What does 'low' signify in this code?
The computer saw the heater control circuit sitting at lower voltage than commanded — the electrical signature of a wire shorted to ground or a heater element that has burned open inside the sensor. It's a more specific finding than the generic circuit code P0056.
What will this repair run me?
Downstream sensors are typically the affordable end of the O2 family, so a shop repair usually lands in the low hundreds all-in, and a DIY sensor swap can cost just the part. A fuse or connector fix, when that's the cause, is dramatically cheaper.
Does P0057 affect an emissions test even though the car runs fine?
It will. OBD testing checks the computer, not the tailpipe feel — an active code and lit light are an automatic fail, and the oxygen-sensor-heater monitor must report complete and passing after repair. How the engine feels and passing inspection are separate questions here.
Related trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0057 from your phone. See our guide to the best OBD2 Bluetooth adapters. Run a repair shop? See Redline for shops.
Generic OBD-II reference. Manufacturer-specific behavior varies. Confirm with a scan tool and, for safety-related codes, a professional inspection. Cost ranges are reference ranges, not quotes.
Seeing P0057 on your car?
Every problem becomes a Case. Tell Redline what the car is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.