P0135 O2 Sensor Heater Circuit error? Focus LS 2006

Smokin Whale · 23-12-2014, 01:14 AM

Hey guys,

Having some minor dramas with my Focus. Getting an O2 Sensor error according to my ODBII tool. The full error is:

Error Code: P0135
O2 Sensor Heater Circuit (Bank 1 Sensor 1)

Sounds like a sensor has played up and the CEL has come on. Cleared the code but came back shortly after. Mechanic said it's somewhere in the exhaust system. Car still runs fine but I think it might be running a little rich - fuel consumption could be better.

Just wondering if anyone knows what part I need to replace this or if there could be some electrical issue causing this that needs addressing. I quickly checked the fuse box and didn't see any issues. If anyone could give some guidance that would be awesome

**russellw** · 23-12-2014, 09:08 AM

Possible causes:

Mechanical: Low battery voltage
Sensor: Contaminated or damaged HEGO Sensor.
Wiring: Wiring open circuit or short circuit.

Cheers
Russ

Smokin Whale · 24-12-2014, 11:30 AM

Quote:

Originally Posted by russellw

Possible causes:

Mechanical: Low battery voltage
Sensor: Contaminated or damaged HEGO Sensor.
Wiring: Wiring open circuit or short circuit.

Cheers
Russ

Battery is 12.05v, seems OK. Looks like sensor may have just failed. Car has 126k KMs so probably time to replace. I don't think it's a wiring issue, although I wouldn't know where or what to test. It just happened randomly one day, nothing has been damaged.

DZFord · 25-12-2014, 09:44 AM

I had the same error, mine failed at 110k KMs or so. I took the opportunity to replace both O2 sensors (Bosch).

The issue is that these sensors have a heater in them, to bring them up to operating temperature more quickly. When this heater / heater wire fails, it throws an error code. The 02 sensor still works, but just takes too long to get up to temperature.

The pre-cat / upstream sensor part number is: 0 258 006 573 (this is your one)
The downstream sensor part numbner is: 0 258 006 569

I think I picked one up from my mate who works at Bosch and the other through ebay as they didn't have stock.

Smokin Whale · 26-12-2014, 11:45 AM

Quote:

Originally Posted by DZFord

I had the same error, mine failed at 110k KMs or so. I took the opportunity to replace both O2 sensors (Bosch).

The issue is that these sensors have a heater in them, to bring them up to operating temperature more quickly. When this heater / heater wire fails, it throws an error code. The 02 sensor still works, but just takes too long to get up to temperature.

The pre-cat / upstream sensor part number is: 0 258 006 573 (this is your one)
The downstream sensor part numbner is: 0 258 006 569

I think I picked one up from my mate who works at Bosch and the other through ebay as they didn't have stock.

Dude, thank you so much. I'll get it sorted. I had thermostat issues for quite some time so it wouldn't surprise me if this would have been related. Is it relatively easy to swap out?

DZFord · 26-12-2014, 12:25 PM

They are easy to swap out, but one of my 02 sensors was pretty jammed up and refused to budge for a while. The new sensors came with anti-sieze on the threads thankfully, and I would have added some one there if they didn't.

The job is made a lot easier with an oxygen sensor socket, which is like a normal socket but with a side cut-out, which gives room for the sensor wires. Just search oxygen sensor socket on ebay.

The thermostat issue may be something separate actually. These commonly fail as well. I used this guide to change mine over: http://fordforums.com.au/showthread....ght=thermostat

Smokin Whale · 29-12-2014, 02:39 AM

Quote:

Originally Posted by DZFord

They are easy to swap out, but one of my 02 sensors was pretty jammed up and refused to budge for a while. The new sensors came with anti-sieze on the threads thankfully, and I would have added some one there if they didn't.

The job is made a lot easier with an oxygen sensor socket, which is like a normal socket but with a side cut-out, which gives room for the sensor wires. Just search oxygen sensor socket on ebay.

The thermostat issue may be something separate actually. These commonly fail as well. I used this guide to change mine over: http://fordforums.com.au/showthread....ght=thermostat

Appreciate the response. On a side note, I'm guessing my local stealership would be the best place to get this part?

Ordered myself the technical manual for this car, will hopefully get my hands dirty on it soon. Already got the thermostat done, was causing too much fuel consumption and I had no time so I took it into my local mechanic. Made a huge difference to the car. Pretty pleased I didn't attempt that one, would have been a bit tricky for me.

marg99 · 29-12-2014, 08:53 AM

getting the Oxy sensor out without the modified socket is very hard, be line ball cost effective to buy the socket and do it yourself verses paying a local mechanic.

Smokin Whale · 30-12-2014, 10:15 PM

Probably bang on there, I'm guessing a standard 22mm oxy sensor socket would be the way to go then. I'll order one online, only $16 or so.

Which type of socket is best? Standard socket or Offset? Or doesn't matter?

Offset:

http://www.ebay.com.au/itm/NEW-Compa...item43d45d3362

Standard:

http://www.ebay.com.au/itm/Sealey-Ox...item51c84d60d7

DZFord · 30-12-2014, 11:58 PM

I used the 22mm standard socket

Smokin Whale · 11-02-2015, 05:41 PM

Hey guys, thought I'd update this thread. I got a PDF technical manual off ebay, then realised it was totally unnecessary since it was such an easy job. Ended up getting the sensor for $125 from Repco (was $147 at the dealer) along with an O2 sensor socket for an extra $14 or so. Job done in less than 10 minutes, all I had to do was remove the engine cover (make sure the car is cold), disconnect the O2 sensor wire on the right hand side, then use your socket to remove the sensor from the back of the exhaust manifold. Swap the new sensor back in, clear the ODB2 codes, and bob's your uncle. Not hard at all.