Electrics: 70: 98 v70 Accelerometer Duff?

[jimathan]

98 v70
Accelerometer Duff?
Does anyone know what the reading should be from the accelerometer when the car is at rest? Mine is reading 6.2G I think it should be 0 what do you think?

[jimathan]

And does anyone know exactly where it is. I know it’s at front behind grill some where but there is a lot of stuff up front and Im not sure which one it is. I need to find it because I think it’s responsible for turning down the boost on the turbo early.

Do you mean the Throttle Position Sensor (TPS) or Mass Air Flow sensor (MAF)?

[jimathan]

No, the Accelerometer measures the vertical acceleration of the car. (Rapid up and down movements at the front) This information is used by the ecu to determine if you are driving over a lot of bumps. Using the information gained, it will, if necessary turn down the turbo boost to stop the wheels from spinning. Also, when driving on a bumpy road, it disables misfire detection. This is because the ecu decides a misfire has taken place if the average acceleration is not as predicted.

Ah, right. Didn't realize our cars were quite that clever

According to my Autodata CD, it's somewhere around the centre of the bulkhead on a 70. On an 850, it's on the front of the ECU box, beside the screenwash filler.

[PNuT]

is this fitted to all cars? will it bring on a light?

[jimathan]

Thanks for that. Vadis says it’s also on the front but ill be dammed if I can find it

[jimathan]

Vadis says its on all cars from 96 I think. It should put the mil lamp on if it goes open or closed circuit, but it does not appear to flag the mil if it just sits at a fixed value. (Ie bust)

It's the bulkhead at the rear on a 70 i.e. the windscreen side, not the radiator. If you can't see it, it might be worth removing the cowl panel and looking under there.

Since it's a G-Force sensor, I would have thought that it should read 1 when stood still rather than 0 (unless it's a space Volvo ).

[jimathan]

Do you mean below the wipers?