Ford focus fault codes p0036 & p0136

[G321]

Hi, just had the engine light come on and the diagnostic has come up with these 2 codes. I think they both apply to each other as a quick Google search said it was a temperature sensor I think in the exhaust. I had hoped it was just an error and tried to reset the codes both on the diagnostic and by disconnecting the battery for a while but neither have worked. Anybody have an experience of this or any ideas on a cure?

[chimp427]

Both those codes refer to an oxygen/lambda sensor problem in the exhaust system, it has an internal heating element to help it warm up quickly.
Chances are the sensor is knackered, the car may have 2 fitted so a better diagnosis would be to let someone with a more sophisticated diagnostic scanner watch the sensor/s activity.

Edited by chimp427 on Thursday 1st October 19:34

[bearman68]

Bank1 Sensor 2 = downstream O2 sensor has failed. Car will drive fine as it is not a part of the control loop. Don't worry about it and carry on regardless. Or splash £100 and have it changed. There's no realistic repair option on this.

Cheers

[G321]

Thanks for the replies guys. I take it would be an mot failure though? Which I'm sure is next month

[andyiley]

As above, it is not part of the control loop, so I THINK you are ok, but others with more detailed info will be along shortly.

[bearman68]

Will be fine for MOT, though might show as advisory (assuming it passes it's emission test as any other car would need to)

Cheers

[Mr2Mike]

The downstream sensor IS used within the closed loop fuel control on some vehicles, so don't assume it's never affects fueling. In these vehicles it is used to optimise the cat operation (e.g. ensure enough oxygen is present) as well as monitor efficiency.

[G321]

Going to try and sort this myself. Had a look underneath and can't see the sensor anywhere. Any ideas before I go and spend £20 on a Haynes manual?

[bearman68]

G321 said:

Going to try and sort this myself. Had a look underneath and can't see the sensor anywhere. Any ideas before I go and spend £20 on a Haynes manual?

It will be downstream of the cat. IIRC the cat is vertically placed coming off the exhaust manifold at the front of the engine. I would anticipate the post cat O2 sensor to be a few inches behind the engine sump, obviously bolted into the exhaust.

But I've had a few beers and wait to be corrected.

[G321]

bearman68 said:

It will be downstream of the cat. IIRC the cat is vertically placed coming off the exhaust manifold at the front of the engine. I would anticipate the post cat O2 sensor to be a few inches behind the engine sump, obviously bolted into the exhaust.

But I've had a few beers and wait to be corrected.

I think you're right. I bought an online Haynes manual and that pretty much confirmed it. Look like it might be awkward to get to though