2003 Fiesta O2 Sensor Issue

[MichaelHumphreys]

Hi all,

I have recently purchased my first car, which happens to be a 53 plate 1.4 Fiesta Zetec and after owning it for around a month the engine management light came on. So I plugged in a basic diognostic checker and found that it was the Heater Control Circuit Bank 1 Sensor 1 that was causing the issue. So I checked the wiring, and the sensor exterior but could not remove the sensor from the engine bay to check it. I erased the engine light and it came straight back on when the engine was started up. SO i took it to the garage and asked them to check the light, replace the sensor and then erase the light. A medium sized garage bill later the sensor was replaced. However the light continues to stay on after replacement and after removing the light.

Does anyone know what else I can check to stop the light coming back? I know jumping to changing the sensor is wrong but I really thought that it was the issue seen as the car was coming up to 70k miles.

Thanks

[iantt]

did they change the correct sensor, there are 2, upstream and downstream of the cat. bank 1 sensor 1 is the upstream one.

check fuse 13 20amp is ok

[MichaelHumphreys]

Hi, thanks for a quick response. They definitely replaces sensor 1 which is located just behind the air filter in the engine bay. I checked the fuse just now and its okay which is a pain as I still haven't found a fix and I'm worried about by cat :/. Thank you though

[Oakley]

Hi,

I have a 2015 MK7 Ford Fiesta Red Edition 1.0 ecoboost 140bhp. The car has just hit the 50k mark and the engine managment light has come on. I tested it with an OBD2 reader and it turns out it was the Oxygen (lamda) Sensor Bank 1 Sensor 1 (pre cat). I managed to get my hands on one and had it replaced and cleared the code using OB2 reader. i drove about two miles and turned the car off and back on and to my suprise the engine managment light came back on, I then reset my ECU by dissconnecting the battery from the car and left it for 10 mins before reconnecting it however the light is still on.

I have read something about drive cycles and how the car needs to go through a certian number of drive cycles before the monitoring system resets and could even be up to 100 Miles. Does anyone know anything about this or anything els i could try or if this drive cycle thing is even a thing?

[Oakley]

Hi,

I have a 2015 MK7 Ford Fiesta Red Edition 1.0 ecoboost 140bhp. The car has just hit the 50k mark and the engine managment light has come on. I tested it with an OBD2 reader and it turns out it was the Oxygen (lamda) Sensor Bank 1 Sensor 1 (pre cat). I managed to get my hands on one and had it replaced and cleared the code using OB2 reader. i drove about two miles and turned the car off and back on and to my suprise the engine managment light came back on, I then reset my ECU by dissconnecting the battery from the car and left it for 10 mins before reconnecting it however the light is still on.

I have read something about drive cycles and how the car needs to go through a certian number of drive cycles before the monitoring system resets and could even be up to 100 Miles. Does anyone know anything about this or anything els i could try or if this drive cycle thing is even a thing?

[stef123]

What was the fault code you got? A fault code relating to an oxygen sensor doesn’t necessarily mean it is faulty in any way.