Downstream O2 sensor circuit fault on bank 1.
P0136 — also written PO136, P 0136, 0136 — is the OBD-II code for o2 sensor circuit (bank 1 sensor 2). Same code, same fix: this page covers every spelling of it.
This code means the car’s 'checker' sensor—the one after the catalytic converter—isn't talking to the computer properly. It's a classic headache on aging Corsas and high-mileage Focus diesels.
P0136 is a sensors fault code, typically costing £80–£350 to put right in a UK garage.
What P0136 actually feels like to drive
- The dreaded amber engine management light (EML) staring you in the face.
- A slight 'ticking' sound from under the car when you first start it from cold.
- Absolutely no difference in how the car drives—it'll pull just fine.
- Failing the MOT on emissions because the secondary O2 sensor won't 'ready up'.
- A faint smell of 'rotten eggs' if the cat is being worked too hard.
What causes P0136?
- Sensor failure
- Wiring damage
UK vehicles that throw P0136 most often
- Vauxhall Corsa D/E 1.2 & 1.4 (A12XER/A14XER) 2006-2018
- Ford Focus 1.6 TDCi (DV6) 2011-2017
- Volkswagen Golf Mk6/Mk7 1.4 TSI 2008-2016
- Nissan Qashqai 1.6 dCi (R9M) 2011-2018
- Honda Civic 1.8 i-VTEC 2006-2012 (common wiring snag)
- BMW 3 Series (E90/F30) 318i/320i N43 engine
How P0136 is fixed
- Sensor replacement
- Wiring repair
The P0136 misdiagnosis that wastes money
I see it all the time—drivers rush to Euro Car Parts, buy the cheapest 'universal' sensor they can find, and then wonder why the light's back on in two days. The real trap with P0136 isn't just a dead sensor; it’s often a hairline crack in the exhaust manifold or a blowing flexi-pipe just upstream. If air leaks in, the sensor reads lean and throws this code. I’ve seen lads swap three sensors only to find the actual fault was a £15 exhaust gasket that had perished. Check the pipework for soot before you touch the electrics.
What a UK garage should charge for P0136
A proper diagnostic plug-in should cost you £40 to £60 at an indie. For the part, a quality Bosch or Denso sensor usually runs between £70 and £130. Labour is typically an hour—call it £60 in the sticks or £100+ in London. If the sensor is seized in the pipe (which they usually are in rainy Scotland), you might pay a bit more for the gas torch treatment. Total bill is usually £180 to £250. Main dealers? You won't see change from £350.
P0136 repair cost in the UK
Most P0136 repairs land between £80–£350 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Bob's tip on P0136
Don't let a garage just tell you 'it’s the sensor.' Insist they check the live data on their scan tool first. A working sensor should stay fairly steady around 0.45V—if it’s flatlining at 0V or swinging wildly, then yeah, it’s toast. Also, ask them to check the heater circuit fuse. On a lot of Vauxhalls and Fords, a blown fuse for something unrelated can share the same circuit, making you think the sensor is dead when it's literally just a 50p fuse. If it is the sensor, demand a Bosch or NTK unit; the 'white box' cheapies are a waste of your time.
Can you drive with P0136?
Drivable.
Urgency: low.