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Old 12-25-2018, 05:04 AM
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wpoll wpoll is offline
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Quote:
Originally Posted by 80stech View Post
@wpoll It's the red portion of the gauge that lights up, If you have it. It will come on with the bulb test when you first start the vehicle or if you activate the dash test or reset.
Will watch for that - not sure I'd miss that but you never know!

I've confirmed the sensor (BMW part # 13621703993) IS the same part on both my E53 AND on my BMW F650GS Dakar motorcycle... and it's MUCH easier to get at on the motorcycle. The second NTC junction isn't used on the motorcycle. On my M57TU, the intake manifold would have to come out to get anywhere near this temp sensor.

So now to try to understand how the DME/DDE uses the various coolant temp sensors. Reading NewTIS I see this on the M54/M62/N62...

Coolant temperature sensor
The coolant-temperature sensor is screwed into the cylinder head and registers the temperature of the coolant by means of its variable resistor (NTC= negative temperature coefficient).

Among other things, the coolant temperature serves as a measured variable for the following functions:

- Start volume calculation
- Injection volume calculation
- Nominal idle speed

In the event of the coolant-temperature sensor failing, a fault code is entered in the DME control unit and a substitute value is calculated from the value of the intake air temperature sensor with the aid of a temperature model.


Seems the M57 diesel complicates things a little...

Coolant temperature sensor
The coolant-temperature sensor is screwed into the cylinder head and registers the coolant temperature by means of its variable resistor (NTC= Negative Temperature Coefficient).

The coolant temperature serves as a measured variable for the following functions:

- Exhaust-gas recirculation
- Injection volume calculation
- Control condition for air conditioning system
- Activation condition for radiator shutter (only M47TU)
- Activation condition for electric auxiliary heater (only M47TU)
- Charge-air-pressure control
- Preheater time control
- Activation of electric fan
- Activation of swirl flaps (only M47TU and M57TU)
- Idle speed control
- Rail pressure control

Troubleshooting
If the coolant-temperature sensor is defective, faults 3EE0, 3EE1 ”Coolant-temperature sensor” can be stored.

Test note
The coolant-temperature sensor is destroyed in the case of short circuit to positive.

Setpoints for resistance check
- Resistance at 20°C: 2.5 - 3.0 kOhm
- Resistance at 50°C: 0.7 - 0.9 kOhm
- Resistance at 100°C: 0.12 - 0.17 kOhm

This diagram shows the two sensors..

https://www.newtis.info/tisv2/a/en/e...engine/aiqOZ59

80stech, I assume you are referring to the NTC resistor between pins 1 & 2 on B6256 as the "gauge side"? Makes sense...

Seems possible that the two functions (engine temp control and monitoring) are totally separated and that it might be possible to get the temp warning lamp to light at a lower temp. I'm thinking it might be a software function within the IKE, so looking down that path right now...
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Wayne
2005 BMW X5 3.0d (b 02/05)
2001 BMW F650GS Dakar (b 06/01)
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