No Cooling Fan Operation
Hello and thank you for any help in advance.
have this car was towed in for overheating. tested and suspected cooling fan module located on fan assembly. Installed new from dealer with no success...I assumed it was shorted because i had ground coming out of the power supply but i shouldve noticed the 60 amp fuse was good still. The problem is pin 27 (black)from ipdm does not ground fan relay...When commanding on it works only through ipdm. Using verus pro i can NOT command on the fans through the ECU. If I ground the relay manually fans run and when scoping signal wire to fan module it shows 5.0 volts...when not commanded that wire scope out at about .4 volts so i assume ground. Im trying to confirm if it is a ipdm problem or ecm problem...wiring diag shoes the cpu is in the ipdm..every fuse in the car has been checked. PCM DOES SHOW UP TO 65 % DUTY CYCLE FOR FAN WHEN AC IS ON...IPDM JUST SHOWS A 1 AT ALL TIMES IS DATA FOR FAN.please assist with what i may be missing. thanks again!
If you can command fans on with ipdm then the driver in the ipdm is good. And you see ecm commanding 65 % butt nothing happens I would suspect ipdm
According to Alldata there should be power on the red wire at fan module connector with KOEO. But of course assuming the pin 27 black wire is grounded. Have you check check continuity between pin 27 and the relay? Ive had corrosion inside the ipdm cause similar issues where the component wont work but will work it you manually ground it. Are you grounding the black wire at the ipdm or at the…
Yes I do see the request and I have tested the wire for good integrity.
Looks like you have a bad ipdm.
New ipdm from dealer same problem...what I did find is that with the launch and snap on I can not make the fan come on commanding through the "ecm" but can command no problem through ipdm...it would seem to me the ecm has lost that function to turn on fan...also when bypassing the relay and duty cycling the fan control unit by touching to ground rapidly it does make the fan slow down and work…
Is there any codes in this vehicle at all? The ECM sends the fan request signal over CAN to the IPDM, seems odd it just wouldn't be able to request fan if it can still communicate.
No faults either module. I agree its strange.
Did you try jumping the pins together on the engine coolant temperature sensor connector? Should force the ecm to command high speed fans.
So I have a used pcm here and I still cant activate the fan through the ecm using snap on...waiting on my mobile guy to come out next week to complete the nats registration. Whats strange is now, the launch doesnt have the actuation function for the fan with the used pcm installed...temp switch is operating normally. No u codes or fault stored in ipdm or pcm. Any other info would be helpful.
Does someone in your area have an Autel scanner. It will handle the NATS for this vehicle. And it may have bi-directional function for PCM to fan.
Elias, The reason that I suggested jumping the ECT is because back in the day I had a GM that would run the fan with the AC or TECH 1 but not based on coolant temperature. Perhaps that would confirm the ECM failure. Randy
This one doesnt even run with the ac on unfortunetley
last new info i have is the alternator duty cycle in ecm shows o and "off" charging voltage is stable at 14.0 volts. i did disconnect battery sense sensor at negative terminal with no change. Im gonna try to scope the signals to alternator but very tight. any one know if the alternator duty at 0 is normal and off? thanks
Alternator operating properly voltage at duty cycle is about 6.4 volts and charging system does react when applying ground. So o is normal...learning a lot with this one.
Well, unfortunately the used pcm would not take even using the consult 3, kept saying failed and then wanted a new pin code. A side note we found that the consult wouldnt do activations with the used pcm either(I believe its locked out till programmed) does anyone know if you can even do a used pcm on this car year model? Will have to see if customer wants to go forward as a new one is 1400.00.
Well its fixed...turns out the guy was at a bodyshop and this happened on the way home...I found that they swapped the ipdm (stole it actually) with one from an altima! We originally ordered one based on the part number in the vehicle(which was wrong)...when we ordered a nother with the vin it worked(different part number)...the price from one to the other was 375 vs 1250!! We think the…