If I unplug the coolant level sensor and nothing happens, its a short ??

[Derek A.]

Given my latest cooling system woes - I have discovered that the low coolant warning is not firing upp. Sensor is free - but if I unplug it nothing happens.

Any tips from m30 owners on where the wires get messed up ?

Thanks

D.-

[632 Regal]

fuse?

[Interceptor]

Given my latest cooling system woes - I have discovered that the low coolant warning is not firing upp. Sensor is free - but if I unplug it nothing happens.

Any tips from m30 owners on where the wires get messed up ?
I doubt it's a short - in 99% of the cases the problem is the corroded/oxidized plug/connector and it results in constant bitching about coolant level. You should check the fuse as Jeff suggested and then try cleaning/swapping the sensor.

[Derek A.]

I am not getting any bitching about the coolant level - that is the problem. If I udnerstand correctly the switch is closed no messsage, once it opens you get a message. So if I unplug the sensor - I should get a warning...right ??

Is there a special fuse for this ?

[Gooch]

The wiring might be opposite of what you state where the sensor is always open and closes when when the level is low. If you short it the plug and the low coolant message comes on then the sensor is bad.

[Gooch]

The wiring might be opposite of what you state where the sensor is always open and closes when when the level is low. If you short the plug and the low coolant message comes on then the sensor is bad.

[Bellicose Right Winger]

Correct. According to ETM page 6200.0-11 the level switch opens on low level. Disconnecting level switch will have the same effect and should turn on warning msg. These devices are intentionally wired this way to check for both low level and wiring problems. It's a type of supervised circuitry.
Check control module may be bad or disabled. Fuses 1 and 20 power CC module. Can you force any other check control warnings? open door, lights on, low washer fluid, etc?

Paul Shovestul




I am not getting any bitching about the coolant level - that is the problem. If I udnerstand correctly the switch is closed no messsage, once it opens you get a message. So if I unplug the sensor - I should get a warning...right ??

Is there a special fuse for this ?

[uscharalph]

Correct. According to ETM page 6200.0-11 the level switch opens on low level. Disconnecting level switch will have the same effect and should turn on warning msg. These devices are intentionally wired this way to check for both low level and wiring problems. It's a type of supervised circuitry.
Check control module may be bad or disabled. Fuses 1 and 20 power CC module. Can you force any other check control warnings? open door, lights on, low washer fluid, etc?

Paul Shovestul
That Coolant Level Sensor is a PITA!

[Derek A.]

That Coolant Level Sensor is a PITA!
Its right in the top of the resvoir - takes 2 secondds to pull out. Its not an m50 which has them buried in the radiator.

[Javier]

then check CCM fuses F1 and F20 (but bad fuses should reveal other symptoms, so I doubt it).

The wire coming from CCM is the Brown/White one, when the sensor is unplugged, this wire should have some voltage, if not, either the CCM metering resistor (inside CCM from pin 4) is bad, or the wire is shorted to ground between CCM and the sensor connector, remove CCM and check continuity to ground to debug. It is a straight wire from CCM connector to level sensor.

Javier

[Derek A.]

WTF - now its working. Damn car is getting on my nerves

[uscharalph]

WTF - now its working. Damn car is getting on my nerves
Gremlins!

[uscharalph]

Its right in the top of the resvoir - takes 2 secondds to pull out. Its not an m50 which has them buried in the radiator.
It's not the changing of it, it's the fact that they're so tempermental, at least on my car.

[shadowpuck]

then check CCM fuses F1 and F20 (but bad fuses should reveal other symptoms, so I doubt it).

The wire coming from CCM is the Brown/White one, when the sensor is unplugged, this wire should have some voltage, if not, either the CCM metering resistor (inside CCM from pin 4) is bad, or the wire is shorted to ground between CCM and the sensor connector, remove CCM and check continuity to ground to debug. It is a straight wire from CCM connector to level sensor.

Javier

Sorry to bring back an old thread - just wondering if these instructions would apply to a 02/93 build 525i. I've replaced the coolant level sensor and thoroughly cleaned the connector but I still get constant coolant level warnings upon startup and shutdown.

I have no other bizarre check module errors - I'm considering myself lucky! :)