Can I drive with P0136?

Yes, for short distances. The downstream sensor mainly monitors catalytic converter efficiency, so it does not directly affect how the engine runs. It is likely to be picked up at an emissions check, though, and you may miss a developing converter issue if you ignore it for weeks.

How long does a downstream O2 sensor last?

There is no fixed lifespan. Downstream sensors sit in cooler exhaust gas after the catalytic converter and usually outlast the upstream sensor, but oil burning, coolant leaks and silicone sealants can shorten the life of either.

Is the upstream or downstream sensor more important?

The upstream sensor is more critical because it controls real-time fuel mixture. The downstream sensor monitors converter health and only makes small fuel trim corrections. A failed downstream sensor will not stop the car from running properly.

Will P0136 fail an emissions test?

It can. Each country writes its own inspection rules and grades defects its own way, but a lit check engine light with a stored emissions code is the kind of fault that gets a car rejected in many inspections, and readiness monitors that have not completed can hold the test up as well. Fix it before the appointment rather than hoping.

P0136: O2 Sensor Circuit Malfunction (Bank 1, Sensor 2)

Quick Answer

Safe to drive (short-term)

P0136 means the downstream oxygen sensor on Bank 1 (post-catalyst, Sensor 2) is producing a voltage signal outside the expected operating range. This sensor monitors how well the catalytic converter is cleaning exhaust gases. A failing sensor or a degrading converter can both trigger this code.

Severity: Moderate · Emissions
Estimated repair cost: From €45 to €310+, varies by vehicle

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What does P0136 mean?

P0136 is a emissions-related diagnostic trouble code classified as moderate severity. When your vehicle's ECU detects this condition, it stores P0136 and illuminates the check engine light.

Where it is on the car

Engine
Oxygen sensor before the converter (sensor 1)
Catalytic converter
Oxygen sensor after the converter (sensor 2, or 3 on some cars)
Silencer and tailpipe

What are the symptoms of P0136?

If your vehicle has triggered P0136, you may notice one or more of these symptoms:

Check engine light illuminated
Slight decrease in fuel economy
Possible failed emissions test
No noticeable change in driveability in most cases
May appear alongside P0420 if the converter is also degrading

What causes P0136?

Here are the most common causes of P0136:

Failing or aged downstream O2 sensor (Bank 1, Sensor 2)
: high
Damaged or corroded O2 sensor wiring/connector
: medium
Exhaust leak between catalytic converter and downstream sensor
: medium
Degrading catalytic converter causing sensor signal drift
: low
Coolant or oil contamination of sensor element
: low

Is it safe to drive with P0136?

Generally yes, for short-term driving. Safe to drive short term. The downstream sensor mainly monitors catalyst efficiency, so fuel mixture control is largely unaffected. It is the sort of fault that gets a car rejected at an emissions check, and you risk masking a developing converter problem if you ignore it.

How do you diagnose P0136?

Follow these steps to pinpoint the root cause of P0136:

Read freeze frame data to capture the engine conditions when the code was set (RPM, coolant temp, load)
Inspect the exhaust system between the catalytic converter and the downstream sensor for cracks, loose clamps, or gasket leaks
Inspect the Bank 1 Sensor 2 connector and wiring for corrosion, heat damage, or chafing against the heat shield
Use a scan tool to view live O2 sensor data. The downstream sensor should show a relatively flat voltage around 0.6-0.8V at operating temperature, not the rapid switching of the upstream sensor
Compare upstream vs downstream waveforms. If both switch identically, the converter is likely failing. If the downstream is erratic or stuck, replace the sensor

How much does P0136 cost to fix?

Repair costs for P0136 vary depending on the root cause and your vehicle. Here are typical estimates:

Repair	Parts Cost	Labor Cost	Total Estimate	DIY Difficulty
Replace downstream O2 sensor (Bank 1, Sensor 2)	€40–€180	€50–€130	€90–€310	Moderate
Repair O2 sensor wiring or connector	€5–€25	€40–€120	€45–€145	Moderate
Fix exhaust leak near downstream sensor	€15–€90	€60–€200	€75–€290	Moderate

Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.

Full repair guides

Oxygen Sensor Replacement Cost

P0136 on specific vehicles

P0136 behaves differently depending on your vehicle. Select your car below for model-specific causes and known issues:

P0136 on BMW

BMW 3 Series

See BMW-specific causes & cost

P0136 on Volkswagen

Volkswagen Golf

See Volkswagen-specific causes & cost

P0136 on Audi

Audi A4

See Audi-specific causes & cost

P0136 on Mercedes-Benz

Mercedes C-Class

See Mercedes-Benz-specific causes & cost

These codes are often seen alongside P0136 or indicate related issues:

Common questions about P0136

Can I drive with P0136?: Yes, for short distances. The downstream sensor mainly monitors catalytic converter efficiency, so it does not directly affect how the engine runs. It is likely to be picked up at an emissions check, though, and you may miss a developing converter issue if you ignore it for weeks.
How long does a downstream O2 sensor last?: There is no fixed lifespan. Downstream sensors sit in cooler exhaust gas after the catalytic converter and usually outlast the upstream sensor, but oil burning, coolant leaks and silicone sealants can shorten the life of either.
Is the upstream or downstream sensor more important?: The upstream sensor is more critical because it controls real-time fuel mixture. The downstream sensor monitors converter health and only makes small fuel trim corrections. A failed downstream sensor will not stop the car from running properly.
Will P0136 fail an emissions test?: It can. Each country writes its own inspection rules and grades defects its own way, but a lit check engine light with a stored emissions code is the kind of fault that gets a car rejected in many inspections, and readiness monitors that have not completed can hold the test up as well. Fix it before the appointment rather than hoping.

Read our detailed guides

Scan your car with Skanyx to diagnose P0136

Your car logged P0136. Skanyx reads it on a standard OBD2 adapter (Bluetooth LE on iPhone), tells you whether it is safe to keep driving, and shows the €45-€310 repair range so you know the number before a shop quotes you. Free on iPhone and Android, and you do not need to be a mechanic to read it.