Diagnosis charges for BMW

bmw
528

#1

I think I have a faulty sensor in my BMW. The display shows the outside temp as -40 F. Will it really affect the working of the car??? Could it be the reason for my wipers not coming on??? Any estimate for the diagnostic charges at a Mechanic??


#2

Forget the temperature display for the short term. Your primary concern is the loss of windshield wipers.
I cannot imagine that the wiper function is in any way linked to the temperature display except by the way of a common fuse. Even that is a stretch.
Check your fuses though, first.
If you don’t have a blown fuse, get the wipers working via a professional mechanic right away. You can do without the temperature gauge, but you need working wipers.


#3

This sensor is for your information only. It is not used by the ECM to control any of the engine systems. It is OK to ignore this unless the CEL is on.

The wipers not working is probably a completely different problem, or it may be related if the sensor wires travel together with the wiper wires. Hard to tell through the internet.

Check with your owner’s manual and see if the fuse for the wipers is blown or not. A $0.20 fuse is cheaper than any diagnostic fee a mechanic will charge.

ADDED: You seem to be having a lot of issues with this car lately. What year is it and how many miles?


#4

Its a 2000 BMW 528i with 125000 miles on it. BTW my mechanic said that the wipers not working could be due to the faulty sensor sensing the ambient temp as -40 F. For the ECM its snow and ice all around so the wipers may not be working.


#5

my mechanic said that the wipers not working could be due to the faulty sensor sensing the ambient temp as -40 F. For the ECM its snow and ice all around so the wipers may not be working.


#6

If that is the case, the ambient temp sensor should be located near the front grille or near the front bumper lower valence. It should be easy to check with a multimeter looking for resistance (OHMS). If the sensor shows an open circuit (infinity), replace the sensor. If the sensor shows ANY resistance in the Mega-ohm or Kilo-ohm range, check the circuit. There may be a break in a wire.


#7

I have seen this -40F display when the display module needed what BMW calls “coding” and the rest of the world calls programing. The question is why did your module (which BMW calls IKHA or IKHV)and everybody else calls HVAC lose its coding.

I can’t remember any function being inhibited when the display is wrong.

So first step is an attempt to re-code the module (always seems to be the first step after checking bulletins with BMW).