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Discussion Starter · #1 ·
Good day,
I have 2004 touareg 2.5tdi r5 a/t
When i turned the ignition on, the fan immediately run on hispeed and would not stop.
I have dtc 16501 engine coolant temp sensor 1 circuit low
I see that there are many people having problem with fan stays on when the engine off, but mine is as assoon as ignition on, the fan run on hispeed
i have changer the coolant temp sensor 1, thermostat and also the temp sensor radiator. But it still run on highspeed.. the airconditioning is off and the car have trouble starting and on idle. I believe there is a short somewhere but i could not find one. 2 heater plugs was damage, i changed it to a new one, thinking that the hard start was caused by it; but it still the same. I have benched test the fuel pump and its running fine. With only coolant temp dtc clue; i have stuck in a wall now. I believe if i fix this constantly running fan i can solve the other peoblem.
Can anyone shed somelight?
Also i have swapped and check the fuse & circulation coolant relay and no luck. If the fan module itself is the problem; wouldnt the fan not work at all? And would it not be two of them keep running on hispeed
Btw im using autel maxisys elite
 

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Discussion Starter · #3 ·
Can you read values off the G62? You may need to trace the wires back to the ECU to see if you have a short if you can't see values.
Thank you sir, Yes I can see the value; during ignition on and engine cold, sensor coolant temp 1 (which goes near the intake) reads around 34celcius and sensor temp 2 (which is the radiator outlet) reads about the same 32/33 as well. When I was able to start the car, the temp 1 would read a higher than temp 2. it would deviates by around 20 degrees celcius. This is where i found that the thermostat was defective; I removed it and tested it on boiling hot water and it would not open; and seal inside the thermostat was ripped. So i changed it as well. But still, im having this same 16501 engine coolant temp sensor 1 circuit low dtc.
Plus the car now have a very long start and could not hold the idle. I'm afraid the fan that run constantly on when ignition on would shorted some other module/sensors; But the only other clue that I can get from autel is a dtc regarding driver access antenna (00179).
 

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The only thing a constantly running fan would do is drain your battery if left with ignition on for long enough.... it wouldn't cause any other "shorts" or damage any sensors\modules.
Are you sure the new sensor is good and there's no connector\wiring issues?
Did you replace the original black sensor with the new green one?
 

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2011 VR6 FSI LUX
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Good day,
I have 2004 touareg 2.5tdi r5 a/t
When i turned the ignition on, the fan immediately run on hispeed and would not stop.
I have dtc 16501 engine coolant temp sensor 1 circuit low
I see that there are many people having problem with fan stays on when the engine off, but mine is as assoon as ignition on, the fan run on hispeed
i have changer the coolant temp sensor 1, thermostat and also the temp sensor radiator. But it still run on highspeed.. the airconditioning is off and the car have trouble starting and on idle. I believe there is a short somewhere but i could not find one. 2 heater plugs was damage, i changed it to a new one, thinking that the hard start was caused by it; but it still the same. I have benched test the fuel pump and its running fine. With only coolant temp dtc clue; i have stuck in a wall now. I believe if i fix this constantly running fan i can solve the other peoblem.
Can anyone shed somelight?
Also i have swapped and check the fuse & circulation coolant relay and no luck. If the fan module itself is the problem; wouldnt the fan not work at all? And would it not be two of them keep running on hispeed
Btw im using autel maxisys elite
Read post #8 of the thread in the link below. Maybe it'll steer you in the right direction.

Link >>>>
 

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Discussion Starter · #6 ·
The only thing a constantly running fan would do is drain your battery if left with ignition on for long enough.... it wouldn't cause any other "shorts" or damage any sensors\modules.
Are you sure the new sensor is good and there's no connector\wiring issues?
Did you replace the original black sensor with the new green one?
Yes i have replaced it with the new original sensor with the green one. Does anyone has the wiring diagram or resistance/voltage spec for tourage r5? sadly i use autel; might need to get myself vcds..
 

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There should be 2 pins on the sensor.
Pin 1 = wire should be green
Pin 2 = wire should be black
Check continuity between the sensor connector and the ECU connector... 60pin... pins 52 & 53....
 

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Discussion Starter · #8 ·
Guys turn out there is one more temperature sensor in the airconditioning gas line. At first i thought it was a pressure sensor. I only found out about it when i do live data from autel on the airconditioning. There was a temperature reading that indicate 0 degree. I pull out the sensor one by one along the gas line and found out it was temperature sensor. Changed it and aircondition is back alive and no more ignition fan hi speed running.
 
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