1998 V70 XC P0108 Barimetric Altitude sensor code

[scot850]

Hi,

I recently sold our old 98 V70XC to a lovely young couple, and told them if they have any problems (the guy is not practically or mechanically inclined) to let me know, especially when a repair shop wanted to charge them $200 to install a new headlight bulb!!

Anyway, they thought the car may have thrown a code as the young lady hadn't tightened the fuel cap enough. I said I'd check it for them and it wasn't an emissions code but the P0108 code for the Barometric Altitude Sensor reading high (is this also called the MAP sensor by some folks?).

In Canada these are stupid expensive ( >$200 CDN), and by luck when I was looking for parts for my car today, I found a 'supposedly good' used Bosch sensor fitted to a 98 S70 being parted out. I'm making the assumption the part is the same in all 98 models. I believe the Volvo part # is : 1275342 and this is a Bosch part # 0 261 230 018. FCP has a Facet part at $90 US but shipping is another $40 US and a 5-8 day shipping time.

Is there any way to test the part without the car being around? I have a 2000 V70R but if it uses this sensor, I don't know where it is fitted as it is not behind the RH headlight as per the 98 XC. Otherwise, I'd just swap it out and try it in my car. Does the 2000 V70R have this part, and is so where is it located, or I there any other way to test the part?

Appreciate the help as always.

Neil.

[rspi]

I believe they are usually mounted on the front of the subframe more towards the passenger side.

[cn90]

1+,

IIRC, it is pink in color and near the pass side HL area. The barometric sensor is an over-engineered device. In theory, you can ignore it and the car still runs fine because air is metered by the MAF.

It is extremely unusual to see this code. So my advice is to remove it, clean it and check the bottom port for any clog.

If you want to replace it, junk yard is much cheaper.

Anyway, info on cleaning it is below:

https://www.matthewsvolvosite.com/forums ... hp?t=53478

[jimmy57]

Your 2000 has that as a circuit board mounted piece so it is not serviceable or visible.
As said already these are very low trouble sensors. Some cars set this code because the lower subframe mounted acceleration sensor gets damaged or the a/c high pressure sensor is faulty. These all share the same power supply circuit out of the ECM so an issue with one can cause a detected fault with another.

[scot850]

Thanks guys.

jimmy57, you say the sensor on a 2000 is a circuit board part. Just curious as IPD list one for my car which is the same part # as for earlier models. Having said that, I can't find the physical part, even though, strangely, the mounting bracket is still fitted behind the RH headlight on inner wing!

I found a supposedly 'good' part on a parts car yesterday for $40 (guy knows how expensive parts are up here as he parts out and repairs Volvos).

Other than sticking the part in, is there no way to test if the part is good with a circuit tester out of the car?

I have noted your point jimmy57 that other items could cause the problems like the A/C or acceleration sensor are on the same circuit.

The guy I bought the part from says they replace the part regularly on older Volvos. I know I did on my 93 850 (I found the old part yesterday). If we lived at sea level or near that, I'd probably not worry about it, but Calgary is at 3600ft elevation, and this part I understand alters the fuel/air mix for altitude. Assuming the part is faulty, is there not a danger of running the engine rich on fuel?

Finally, jimmy, what on earth is the acceleration sensor, and where is it fitted? I can check that for damage and check both contacts and their fuse for corrosion.

Many thanks,

Neil.

[Atis]

The Motronic 4.x uses an external sensor (behind right HL), but from the ME7 ECU it is a surface mounted component on the PCB inside the control unit. There must be black plastic "knob" on the ECU housing, which makes the pressure compensation for the internal pressure sensor.

[precopster]

IPDs listings on that sensor conflict with FCPs which drop the air pressure sensor after '98 for V70s and S70s.

[scot850]

Many thanks guys. Haven't seen the black knob on the ECU box, will have a look for it next time I'm under the hood.

Any takers on what the acceleration sensor is/does? In the spirit of learning, I'd like to know more, and where it is situated on the car.

Neil.

[Atis]

It is a small cylindrical glass, with vacuum enclosed in it, and there is a thin resistor layer on the "lid" of this (obviously it is located inside the plastic housing). As the outer pressure changes, it deforms and the resistance change is processed by the ECU ( I think with a voltage divider). It has 3 pins: ground, signal and +5V. The signal changes from 0.2V to 4.8 according the sensors pressure range and according to the supply voltage as well. I have somewhere a datasheet about that, I will upload it when I get home.

[Atis]

Oh, sorry... you were asking the acceleration sensor... today the morning is too morning...