S40: P0030 code and mil light on

[Caroleuk]

Hi I think I have posted on other questions about this fault however most refer to other models.

I have as stated in the heading a P0030 code •Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 on my car.
I know that it could be an electrical problem fuse, wiring or dirty connecter.
But having said that all the information on were to find the connecter and the sensor itself have proved to be incorrect on my car (an early 2004 which I normally have to look up parts for under the MkI heading)
Can anyone please tell me exactly were the connector and the fuse are with photos if possible, and also the position of the bank1 sensor! on my car again with pictures if possible?

This car is always a problem for me as it falls between the MkI and mkII models, any help would be better than nothing.

Thank you for you help Carole

[bobthecabbage]

Is your car an old s40/v40 from 1996-2004 or one of the new style v40s from 2004 onwards?

This forum only covers the former.

[Caroleuk]

Originally Posted by bobthecabbage

Is your car an old s40/v40 from 1996-2004 or one of the new style v40s from 2004 onwards?

This forum only covers the former.

It's an old s40 early part of 2004 I think it was registered feb/march also 1.6 non turbo

[bobthecabbage]

I am a bit confused as your car should be a phase 2 as it's nowhere near the change over point around 2000.

How long have you had it? I wonder if someone has rebuilt it in the past using a mixture of phase 1 and phase 2 parts?

However when it comes to locating the sensor, it is just a case of following the exhaust back to the engine. The 'silencer' closest to the engine will actually be the catalytic converter and there will usually be one oxygen sensor between this and the engine and one after it.

The sensor between the engine and the catalytic converter is the one you want to prioritise as this is the one that normally controls the air fuel mixture going into the engine. The sensors are screwed into the exhaust and can sometimes be seized in there. There is a special tool for removing it that may be worth having.

Sometimes these sensors can be hard to find but they will usually be visible either from above or below the engine.

[Caroleuk]

Yeh it gets me confused at times.

However thank s for the info, I would like to check the wiring and the fuse before I get a new sensor as it's not normal for these to go bad on there own (usually takes a hit from something) Any idea which fuse it is are were the multi plug will be?

[druid]

Your car, assuming it a car like all the other members have will be a MK1 '96-'04 which is is further split into phases ie. P1 P1.5 and P2.

[ww1dm1]

I believe by Mk2 he meant the post 2004 version. Caroleuk owns a Mk1 P2.

The code stands for O2 sensor heater fault. The connector should be in one of two places. First is at the back of your engine bay, under a black cover in front of the VIN plate. If it's not there - the O2 sensor wire could immediately through the bottom of the car underside and the connector would be somewhere in your floor. To access it you would need to get under the car and pull the rubber plug where the wire goes, connector should be there. Haven't seen them anywhere else, do update where you found it.

[Caroleuk]

Originally Posted by druid

Your car, assuming it a car like all the other members have will be a MK1 '96-'04 which is is further split into phases ie. P1 P1.5 and P2.

Thank you Druid at last I know what my car is, it will make life a lot easier.

[bobthecabbage]

If you can find your engine code which should be listed in the manual, this may make ordering parts easier.

I would be surprised if motor factors cannot distinguish between an old s40 and a new V40 as the reg is linked to the VIN number these days. It did use to be a common thing though!

I don't think there will be a fuse for the O2 sensor alone. It'll probably be driven via the ECU directly (I am just guessing).

You could have a wire chafed through or corrosion in the connector but I think it is also quite likely that the sensor has failed.

There is a guide to troubleshooting the P0030 code here

https://www.yourmechanic.com/article...i-trouble-code

[ww1dm1]

There actually is a fuse for the O2 sensor heater, totally missed the part where Caroleuk asked.

It's in the engine bay fuse box. Don't have a schematic, so can't mark which one. Probably marked as something vague like "engine control" if there is a description on the fuse box cover.

And the Sensor 1 itself (aka front sensor) is on the exhaust, close to the manifold, before the catalytic converter. Can't miss it sticking out to the side.