Non heating lambda sensor

[Revolvo]

So the engine light comes on because the ECU is failing to tell the lambda sensor to heat.

No results for that found on search function. Anyone ever encounter that before?

Specialist says new ECU needed, or existing one examined/reflashed etc?

Help.....

[bilko1]

What is the fault code? It's quite common for the heater circuit to fail in O2 sensors. I doubt it's the ecu, you need a wiring diagram for the O2 sensor circuit then check all wiring and fuses / relays on that circuit.

[Revolvo]

It's saying that the z19 heating element is not drawing a current. Brilliant.

[Gripper1]

It wouldn't draw a current if it's not working

[Revolvo]

It wouldn't draw a current if it's not working

Yes, so it looks, unfortunately, like I'll have to have somebody look very carefully at my ECU. To see what's happened, how to repair. Only fails from cold start, 600 C and I'm laughing but means driving everywhere with VAG COM to reset engine light every time I start-up.

[Gripper1]

No sorry you haven't quite got what I meant by it.

If the heating part of the lambda circuit is open circuit (ie a break in a wire/internal fault on the lambda) you will get no current draw. The ECU is looking for a certain current draw from the sensor on startup and if it doesn't see it, it throws the CEL

The ECU I'm sure will be absolutely fine. You just need a new Lambda.

If you can give the exact code it will help considerably.

[Nobby]

Switch the plugs to the other sides. If the problem moves then it confirms the lambda is faulty. If it stays the same side then could also be wiring

[chunky79]

Switch the plugs to the other sides. If the problem moves then it confirms the lambda is faulty. If it stays the same side then could also be wiring

This would be the easiest thing to do, the plugs are pretty easy to get to too.

Edit, why have you started another thread when you already have one running

[Revolvo]

Thanks guys, tried switching connectors but problem still exists. Probably means that I didn't actually need the new lambdas that were recently fitted.

New thread because i had and "oh no" moment.....

[chunky79]

Sounds like you have a bad connection somewhere. It's making a good connection when warm.

[Revolvo]

Yeah, car going like a bullet, no misfires, no lean running etc. everything good except for that engine light..... Because ECU is not sending current on Z19 lambda sensor heating circuit on start up.

[Nobby]

Try to find the pinout for the lambda sensor at the ECU and check the line for integrity. If your lucky the loom will be in a few sections and you could replace a little bit of it.

I don't think it would be the ECU itself. ECU's generally either work 100% or go completely balls up.

[Shoppinit]

Thanks guys, tried switching connectors but problem still exists. Probably means that I didn't actually need the new lambdas that were recently fitted.

New thread because i had and "oh no" moment.....

Still exists at same bank / sensor?

You sure you're not mixing up the pre- and post cat-sensors?

Also, post your fault codes.