S40: Sensor on front of air filter box

[TomW]

On my 2002 1.8 petrol V40 a lead has broken off where it connects to a sensor on front of the air box behind the battery.
I just found the wire hanging loose and it appears that it should be connected to the sensor circled in red.
What is the purpose of this sensor?
What does the other end of this lead connect to?

[TomW]

Sorry but unable to load up the picture showing everything.

[magnuz]

If it's this part shown in the picture ? Then it's likely to be a vacuum pipe to operate a flap inside the air box, which would move to allow warm air to be drawn through the flexible aluminium pipe, from exhaust manifold (if it's still fitted ?) when engine & outside air temp are cold .

[TomW]

Originally Posted by magnuz

If it's this part shown in the picture ? Then it's likely to be a vacuum pipe to operate a flap inside the air box, which would move to allow warm air to be drawn through the flexible aluminium pipe, from exhaust manifold (if it's still fitted ?) when engine & outside air temp are cold .

Yes that's the one thank you. I don't know when the lead broke off the sensor but for two weeks now the engine has been missing badly after starting. Could this be the reason and is a new sensor and lead straightforward to fit?
Thanks again
Tom

[magnuz]

As this is a vacuum pipe,.. A disconnected pipe will be sucking air in to the engine, which may have a small effect on engine running ?
The thin pipe connects to the round flap actuator on the front of the air box with a rubber pipe connector (red arrow). This pipe then goes around to the back of the air box & attaches to a twin connector on the temperature valve ( yellow arrow). The other pipe from this twin connector then goes under the plastic cover & attaches to the throttle body ( green arrow) ..... see pic
Unless you have the GDI engine?.. then it may be a bit different?

[TomW]

Thanks for the clear instructions. Yes that's same as mine. We have an identical scrap s40 in the yard and I'll be taking the bits off it. That may explain the engine not giving the usual Volvo purr. This one has done 240k and runs like new. I guess oil changes have been done as per book.

[v_forty]

A quick question - which way round do the two pipes on the rear of the air box go? Mine - see picture - look like they're the wrong way around as one crosses over the other?

[IMG][/IMG]

[ITSv40]

Originally Posted by v_forty

A quick question - which way round do the two pipes on the rear of the air box go? Mine - see picture - look like they're the wrong way around as one crosses over the other?

[IMG][/IMG]

This is mine - as it left the factory. Top pipe goes to the front of the airbox, bottom goes to somewhere on the manifold.

[v_forty]

Originally Posted by ITSv40

This is mine - as it left the factory. Top pipe goes to the front of the airbox, bottom goes to somewhere on the manifold.

Thank you - turns out mine is ok, just routed under then back over which doesn't look right.