P0136: O2 Sensor Circuit (Bank 1 Sensor 2)
P0136 means the engine computer has found a problem in the circuit for the downstream oxygen sensor on bank 1, sensor 2, usually the sensor after the catalytic converter. The most common fix is to repair damaged wiring or replace the sensor, typically $150 to $350 at an independent shop.
- Severity
- Moderate
- Can I drive?
- Drive with caution
- DIY?
- Possible with some experience
- Repair cost range
- $90 – $400
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What does P0136 mean?
The bank 1 sensor 2 O2 sensor is the oxygen sensor located after the catalytic converter on the bank with cylinder #1. The engine computer uses it to monitor catalytic converter performance and help confirm the exhaust mixture is being cleaned up properly. P0136 sets when the signal from that sensor is missing, stuck, or out of the expected range. The problem can be caused by a bad sensor, wiring damage, connector corrosion, or a blown heater circuit fuse on some vehicles.
Common symptoms
- Check engine light on
- No obvious drivability symptoms
- Rough idle in some cases
- Poor fuel economy in some cases
- Failed emissions test
- Other O2 or catalyst codes may be present
Causes, fixes and costs
P0136: O2 Sensor Circuit (Bank 1 Sensor 2)
General guide for most cars. Your car may differ.
This code usually will not leave you stranded, but it can keep the car from passing an emissions test and may hide a converter or fuel mixture problem. Stop driving if the engine runs badly, stalls, or if the check engine light starts flashing.
Most likely causes
- 1
Failed bank 1 sensor 2 oxygen sensorHigh
Most cars with P0136 have a sensor that is slow, stuck, or no longer sending a believable signal, especially if the light is on but the car otherwise drives normally.
Quick check: Inspect live data for bank 1 sensor 2; if it stays flat or behaves unlike the upstream sensor, the sensor may be bad.
- 2
Damaged wiring or connector at the sensorHigh
Heat from the exhaust, road debris, or corrosion can interrupt the signal or heater circuit, which often causes an intermittent code or a code that returns right after clearing.
Quick check: Look for melted insulation, broken wires, loose pins, or corrosion at the connector near the exhaust.
- 3
Blown O2 sensor heater fuse or power/ground issueMedium
If the code appears with a heater-related code or the sensor stays cold and inactive after startup, the sensor may not be getting power or ground.
Quick check: Check the related fuse and verify power and ground at the sensor connector with a test light or multimeter.
- 4
Exhaust leak near the sensorLow
A leak before or around the downstream sensor can let outside air in and distort the reading, more likely if there is exhaust noise or soot near the joint.
Quick check: Listen for ticking or hissing at the exhaust and look for soot marks around the sensor or pipe joints.
Can you fix it yourself?
Possible with some experience
Difficulty: Moderate. A DIY repair is possible if you can safely access the sensor and have basic tools like a scan tool, jack stands, and a multimeter. Ask the mechanic to verify the downstream sensor signal, wiring integrity, and heater power before replacing parts.
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- Scan for stored and pending codes
- Inspect the sensor connector and harness for damage
- Check live data for bank 1 sensor 2 operation
- Verify fuse, power, and ground if the sensor has a heater circuit
- Repair wiring or replace the sensor if tests fail
- Clear codes and road test
- Confirm the code does not return
Estimated repair cost
$150 – $350
Replace bank 1 sensor 2 oxygen sensor: parts and labor
- Repair sensor wiring or connector$120 – $300
- Replace O2 sensor heater fuse or repair power feed$90 – $220
- Repair exhaust leak near sensor$100 – $400
Prices vary by vehicle, rust, engine layout, and local labor rates.
Frequently asked questions
Can I drive with code P0136?
Usually yes for a short time, if the car runs normally and the check engine light is steady. Get it checked soon because the fault can affect emissions testing and may mask a bigger exhaust or sensor problem.
Will P0136 clear itself?
It might turn off temporarily if the problem is intermittent, but it usually comes back if the fault is still there. Clearing the code without fixing the cause is usually only a short-term reset.
Can a bad catalytic converter cause P0136?
A failing converter can sometimes affect downstream O2 sensor readings, but P0136 is first and foremost a circuit or sensor fault. The sensor and its wiring should be tested before blaming the converter.
Is bank 1 sensor 2 the upstream or downstream sensor?
It is the downstream sensor, located after the catalytic converter on bank 1. Bank 1 is the side of the engine with cylinder number 1.
Can I fix P0136 myself?
Maybe, if the issue is a loose connector, damaged wire, or a sensor that is easy to access. If diagnosis requires live-data testing, fuse checks, or exhaust repairs, a shop is often the faster and safer choice.
Related codes
- P0137 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2)
- P0138 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
- P0139 O2 Sensor Circuit Slow OBDResponse (Bank 1 Sensor 2)
- P0140 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 2)
- P0135 O2 Sensor Heater Circuit (Bank 1 Sensor 1)
- P0420 Catalyst System Efficiency Below Threshold (Bank 1)
Related problems
This guide covers most cars and is general advice, not an inspection. Prices are typical US independent-shop ranges and vary by region, car and shop. If your brakes, steering or a warning light feel unsafe, stop driving and contact a mechanic.