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SL-Class (R230) 2003 -- 2012: Discussion on the SL500, SL550, SL600

SL/R230: Sl500 Engine temperature light red and fan on constantly

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Old Jul 2, 2017 | 07:06 AM
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sl500 2002
Sl500 Engine temperature light red and fan on constantly
Hi I own a 2002 sl500 R230 and basicaly my water temperature symbol is red even when cold and the radiator fan is on a full speed all the time, I had to unplug it so it doesnt burn out and cant seem to find any info online about similar problems with other owners cars.
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Old Jul 2, 2017 | 01:08 PM
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Sounds like a bad temperature sensor. It's located on the front of the engine, to the left of the thermostat as you stand looking at it.
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Old Jul 3, 2017 | 08:25 AM
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sl500 2002
Thanks for the reply Rudeney I cannot find the correct part online is it the coolant sensor or just a temperature sensor.

Thanks
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Old Jul 3, 2017 | 11:28 AM
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It's the engine coolant temperature sensor: A0009050700. I can't guarantee that's the culprit, but it sounds likely.
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Old Jul 5, 2017 | 06:28 AM
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sl500 2002
Hi I changed the sensor but still the same, the message on my dash is coolant visit workshop, the coolant is at the top but i put a bit more in just to make sure and still the red water temperature symbol is on from cold and fan is on aswell all the time, could it be the coolant level sensor that goes into the bottom of the coolant resevoir tank?
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Old Jul 5, 2017 | 02:36 PM
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It could be a defective fan control module. The ECU controls the fan speed, but if it can't talk, the fan controller will default to high speed and I think it also triggers a coolant warning. Have you pulled codes?
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Old Jul 6, 2017 | 05:50 PM
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sl500 2002
Ok Thanks for the info, I had a diagnostic test done but it wasnt using the Star system but a more basic Delphi diagnostic but the only relevant fault code I could find was P2073 ENGINE/SUCTION FAN. P20B7 IDLE SPEED INCREASE.

Not sure if these codes are anything to do with the radiator fan.
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Old Jul 6, 2017 | 08:55 PM
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P2073 - [1] Electric suction fan for engine or air conditioning : Short circuit to positive (P1999)
P2073 - [2] Electric suction fan for engine or air conditioning : Short circuit to ground / Check suction fan control module. (P1999)
P2073 - [4] Electric suction fan for engine or air conditioning : Open circuit (P1999)
Sounds like it could be a wiring issue with the fan.
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Old Jun 4, 2018 | 02:25 PM
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Originally Posted by H24k
Ok Thanks for the info, I had a diagnostic test done but it wasnt using the Star system but a more basic Delphi diagnostic but the only relevant fault code I could find was P2073 ENGINE/SUCTION FAN. P20B7 IDLE SPEED INCREASE.

Not sure if these codes are anything to do with the radiator fan.
Did you solve the issue ? I have the same problem and I am very dissapointed...

Thank's for your help...
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