Thread: Fan always on
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Old 10-20-2018, 10:59 AM   #3
far2grumpy
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Join Date: Oct 2008
Location: Cedar Rapids, IA
Posts: 8,121
 

2005 VUE 3.5L
2007 VUE 3.5L
Default Re: Fan always on

Quote:
Originally Posted by pocomenomosso View Post
P0481 code. Malfunction on high speed cooling fan control circuit

Fan comes only after I've started the car and then it stays on.

It does not come on when I turn the key to the ON position, with engine off.

Relays are fine and are not stuck.

The ECT and the IAT sensors are fine and reading rational temperatures. Engine load is OK. TPS position sensors are OK.

Using a scanner, while the car is running I can turn off the fan by the commanding the computer to turn it off. And when I command the ECM again to turn on, the fans will kick on.

So what in the world is going on here?

Maybe I will need to check the A/C stuff? I am rather jaded with the car stuff lately. I've had to trouble shoot and fix multiple problems the past 4 months and, always on weekends where I have the most work to do.
I don't have experience with 2.2 but have circuit diagrams.

P0481 is set when ECM detects an open circuit (0 volts) between ECM C1-13 and COOL FAN HIGH relay contact 86.

Are you positive the fan is running high speed? You could remove COOL HIGH 40A fuse to be certain.

If fan is running LO SPEED and ECM detects P0481 condition the ECM could default to run fan LO SPEED whenever RPM is detected.

Another possibility ... AC could be running (would not explain code P0481) because: (1) AC refrigerant pressure sensor is faulty, or (2) compressor clutch is latched because HVAC is in AC mode (compressor will run but LED will not be lighted if mode switch is set to DEFROST/DEFOG or FLOOR) and fan switch is set to any speed other than OFF.

I have several diagrams ... PM email address if you'd like to have them.

...
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