replaced ambient temp sensor but still reads -40

[areif]

Hi,

Hit a rut in a 97 540i and lost the ambient temp sensor. Replaced it with a new one from the dealer, but it's still reading -40.

I checked the two wires coming to the sensor with a multimeter and one definitely seems to be power and the other ground. The dealer even swapped the new sensor with another, so I don't think the sensor itself is faulty.

How quickly should the temp read something other than -40? I know it can take a couple of days to calibrate, but how soon should I be seeing a change? Did drive the car for almost a week with the new sensor installed, still reads -40.

Any ideas?

- Alex.

[632 Regal]

is it wet there as in rain? If water is involved mine read things for a week til it was 80 degrees.

[areif]

is it wet there as in rain? If water is involved mine read things for a week til it was 80 degrees.

No, it's not wet at all. We get a constant -40 reading, even after almost a week of driving.

[632 Regal]

sorry had to, you say the wires look good and this has done it since you hit a crater, common sence now dictates that something either blew or got loose such as a ground connect. Follow the ground wire to the ground and clean re-connect, follow the pos wire and trace that back to source. Something stupids wrong here! Im surprized that is the only problem, hopefully you got very lucky!

[Phil Sanderson]

try this link http://bmwe32.student.utwente.nl/ and go to "OBC temp at -30".
Maybe your problem.

Phil