Just last week COW (chuck) was in town and I got the booster, A6 tune, Vararam intake, and 165 stat. Took the car out last night and after about 20 minutes, I noticed the temp rising to 228, then the engine light comes on. This morning I scan the code and find that both Fan Controller Circuits are not working. Has anyone had this problem after a tune and is there a known fix for it other than reprogramming the fans? I tried resetting the ECM a couple of times by removing battery cable for 30 minutes, but it comes right back on after a couple of cycles. Any help would be appreciated.
Thanks
I am searching through previous threads on this code, checked the fan fuse, its ok.

 

Hi...... I am looking at the Service Manual for a 2008 Corvette. Volume #2, pg. 9-295. Code P0480 is the DTC Descriptor for "Cooling Fan Speed Output Circuit".

Did Chuck actually tune your car? Or did you just purchase the parts? I know you mentioned "tune", so forgive the question if you did have it tuned.....

When you were replacing the thermostat.......did you bump the fan harness at all?

I do want to make it clear.....I AM NO EXPERT!!!!!.......I read your thread, saw no responses as of yet, and wanted to try and help. I have the three bibles that the technicians use but only for an '08......... It gives the codes and diagnostics...... The first thing to check will be all your connections. Disconnect the harness from the fan and clean it with a "Mass-Flo Sensor Cleaner" by spraying the connectors. There is a chance that you will have to have a tuner make some adjustments to the ECM. One issue you might have is P0128 which will trigger the light if you are running below 167* for several cycles. That code may have to be turned off or disengaged also. I had the same problem. It will trigger the light and shut off your temperature gauge from working and you won't be able to turn on the air conditioner when that happens either. Be patient and do not get discouraged..... I hope this helps a little until Chuck or some of the real 'Experts' read your thread......

JML

 

Yes, Chuck actually tuned it. Good suggestion as far as the harness goes. It is in a very exposed place (easily bummped). I unplugged the connector, inspected it, then plugged it back in. I have reset the ECM and will check to see if the connector just got bumped.
Thanks!!

 

Ok, just ran it for a few minutes, no fan, even when I turn on A/C. I also am listening for the fan relay to click and I havent heard that today either. Last night when i was checking the thermostat, I could swear I heard the fan relays clicking. But not today.

 

Start the car and take a look at your temperature gauge...... Is it giving you a reading? Even though you checked the connection....clean it...it is just to be sure.... Also, I do not know what temperature Chuck set your fans at. They won't come on if the engine is cool..

JML

 

Yes, the temp is at approx. 185 (idling). That is high in comparison to what it was reading when the 160 stat was installed. We had it idling for a long time during the tune and it never climbed over 170. However, you make a good point, the temp for the fans to
"turn on" may not have been reached yet. I will take it for a spin and see what happens.
Thanks again

 

Lonnyh..... Before you take your spin. Disconnect the battery removing negative ground first followed by the positive. I was told by a technician, that you can re-set the ECM better by touching the two poles together for about 10 seconds. JUST THE TWO POLES NOT WITH ANYTHING CONNECTED TO THE BATTERY...... just common sense would tell you that anyway..... I have done it many many times and so have others I know of.... you decide if you want to try it. It will at least re-set back to what Chuck installed in the beginning before the problem. If the problem still exists after cleaning the connectors the light may still get triggered again.....

JML

 

Ok, I will try this, Ive been doing it the lazy way (just the positve cable). Thanks JML

 

After taking it for a drive, the ECM did not throw the P0480 code. It ran at approx. 178. However , when I pulled into the garage I left the engine running the fan did not come on. Observed the temp increase to 200, still no fan. So I guess my test was inconclusive, need to drive it further to see if the code comes up. Will let you know what happens.
Thanks for your help, I think the reset method you advised helped reset the ECM better than the way I was doing it.

 

Your welcome.... Like I said.....I am no expert but I can read, comprehend and at least attempt to help....lol. Did you get a chance to spray "Mass-Flo Sensor Spray" on the connections and clean them? Even though they 'look' good, if any coolant got on the connection or it is just dirty, it can be so even though it does not appear to be to the naked eye. And again....I believe you already checked it.....the 60 AMP fuse at location #25?

 

That will be my next attempt, I got back in the car and as soon as I turned it on the code came up. I need to make sure this is not something with hardware so I dont waste all the time and effort sending the ECM in to Chuck. I am assuming I can pick up the Mass-Flo sensor spray at auto-zone? I am also going to attempt to see if there is voltage on the connector to the fan, I am thinking if I disconnect it and put a volt meter on the ECM side I should see voltage there if the temperature is at "fan on" temp. Also, still want to check relay operation, it really bothers me that I havent heard them actuate today. If they are not closing, then they could have failed or the ECM isnt telling them to.. All I have found so far is the 60 amp fuse in the fuse box (location 25). I will open the manuals tonight to find the relay. I have the 2011 manuals, I just havent had a chance to look into them about this problem yet, Im still at work.

 

Your on the right track then. You can test your fan by making a fuse jumper. Run a wire with a 60 amp fuse in it. Install appropriate fused jumpers between terminals 1 and 4 power and ground. The cooling fan should activate at full speed. If it does not, book says to replace the cooling fan. I really think it is something far more simple than that.... I wish you the best. I will check back.....sorry you have to work on a Saturday....lol.

JML

 

Do you know what the fan speeds were set to? It's possible that if they were commanded at 100%, you may have burned something up. They should be a max of 90.

 

(Good Question)No, I dont know the fan speed settings, but I can find out Monday when I speak with Chuck (COW) about this. I dont think he would have set them to 100%. I have only driven the car a couple of times (around the block) since I had the fan speed re-progammed and never heard the fan running at high speeds. I am also considering taking to England Green down here in Houston to see if they can reprogram the fan speed with their scanner. Thanks for the response.

 

Wow, this just keeps getting worse!! Ok, I have now had a new ECM with a new flashed program installed on it and still no fan (2 weeks into nightmare). My back is against the wall here, I have made an appointment to take it to the dealer on Monday to see if they can find the problem. My fear is that they will red flag my warranty because I have tuning mods in the program. I dont want to have the program removed because that just seems like a waste of time. I have been informed that they can determine if a program has been modified then removed. This is my last chance to try to find any help out there with this, I am pretty sure they will find that I have altered fan speeds and temperature settings in the program. It is my hope that my tuning modifications will not even be detected and the fan problem is hardware. My question is, should I take it to the dealer or just replace the fan myself, the fan assembly if 450.00 well worth a warranty try, but will they viod my warranty because of the tuning?

 

Can you move the fans by hand? Unhook the battery before trying this. I drove down my parent's alley and as all the dirt flipped up, a small piece got stuck in the fan by the shaft. Gave the blade a good jerk and it broke loose.

Have you jumped the power and ground yet? The free moving of the fan and jumping the fan will probably eliminate the trip to the dealer.

 

Yes, I have run the fan with 12 volts and it spins fast , it does get the jump wire hot in only a couple of seconds and I am not sure if this is indicating the coil on the fan is bad, or the fan is simply draiwing the full amp load. It could still be the wiring, however to replace the cable assembly to the fan module you have to replace the entire fan assembly, it is hard wired to the fan ans fan module.

thanks for your help.

 

Take it to someone local and have them review the tune.

 

That was my initial intent, I was going to take it to England Green here in Houston, however, chuck (COW) wanted to send me another ECM to try, After he looked at the tune himself. He has also remoted into a computer hooked up to my ECM and they can find nothing wrong with the tune.
Thanks again for any help

 

if the tech has to log in with ur ecm your powertrain warranty is probably going to be voided. If he doesn't and he's not a jerk then you maybe ok.