Make a donation

Author Topic: 1.4tsi lambda sensors  (Read 990 times)

Offline rOcKoN

  • Just Arrived
  • **
  • Thank You
  • -Given: 0
  • -Receive: 1
  • Posts: 23
    • Email
1.4tsi lambda sensors
« on: March 18, 2022, 01:13:40 pm »
Hello guys,

I try to measure my lambda sensors using carly and I get 0 readings. The car is working fine(I think) without any fault codes.
The thing that gets me thinking is that the car had a custom remap years ago and the tuner might have disabled the fault codes and sensors? Is that possible? How can I tell if my lambda sensors are dead or just disabled?

I am on the verge of buying for the front and rear to replace or go for a new tune first?

Any help is appreciated.

Offline pudding

  • Global Moderator
  • Just look at my post count
  • *
  • Thank You
  • -Given: 2
  • -Receive: 690
  • Posts: 8353
Re: 1.4tsi lambda sensors
« Reply #1 on: March 18, 2022, 03:15:23 pm »
Does Carly show lambda voltage or AFR? 

Coding out the rear sensor (post catalyst) is normal practice with remaps but coding out the front sensor (Pre catalyst) is very dumb.

If the sensors are dead, they generally stick at a certain voltage.  If they show nothing at all, it's either the scan tool or as you say, they have been coded out.


2007 ED30 | 2009 TDI 140 | 2016 BMW 330D

Offline rOcKoN

  • Just Arrived
  • **
  • Thank You
  • -Given: 0
  • -Receive: 1
  • Posts: 23
    • Email
Re: 1.4tsi lambda sensors
« Reply #2 on: March 21, 2022, 08:51:36 am »
Does Carly show lambda voltage or AFR? 

Coding out the rear sensor (post catalyst) is normal practice with remaps but coding out the front sensor (Pre catalyst) is very dumb.

If the sensors are dead, they generally stick at a certain voltage.  If they show nothing at all, it's either the scan tool or as you say, they have been coded out.

AFR no, lambda voltage I think it does. It does check catalyst temperature which I guess is done by the lambda sensor? Just a guess. It also has a measurement for Delta Lambda Bank 1 and 2 which logs 0ms and never changes. We also checked both lambda sensors using my mechanic's scanner and that also showed 0 so can they both be coded out? If so then do I have to go and have the car remapped again?
I will check today about voltage and let you know.
I also have VCDS which does log AFR if I am not mistaken but try to avoid using it as if my laptop is too bulky to have in the car.