P0480 code when A/C is engaged
07-01-2015, 01:01 PM
#1
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P0480 code when A/C is engaged Recently added Classic Air to my LS3 Chevelle and after charging and running A/C for first time I am receiving an error code P0480 Fan Relay. The air is working, both fans are running and engine holding steady temp of 195. Why am I getting this code? Is it in the programming perhaps? Thanks for your help.
07-01-2015, 01:33 PM
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Dual Ford windstar fans are wired thru painless relay 30117. Three relay setup third relay attached to A/C power on. ECU only controls fans by temp. Trying to find someone with similar setup I can compare wiring to.I think the ECU is throwing code because both fans come on with A/C engaged( as it is supposed to)Everything operates correctly, A/C cold, engine running at 195-200 with a/c on. Called both Painless and Classic Air over a dozen times each and neither know what is correct for LS setup. They sell the product for swaps but dont have the support or working knowledge..go figure
07-01-2015, 02:45 PM
#4
Found this:
The P0480 code is detected when the Powertrain Control Module (PCM) detects that the commanded state of the driver and the actual state of the control circuit do not match.
So I take it your AC control relay is spliced into the ECU control circtuit to ground your relays. The ECU then sees that it's control wires are grounded although it has not commanded them to ground.
http://engine-codes.com/p0480_chevrolet.html
Hopefully someone has experienced this and knows of a fix. I think you could solve this with another relay for isolation, but there may be an easier solution.
The P0480 code is detected when the Powertrain Control Module (PCM) detects that the commanded state of the driver and the actual state of the control circuit do not match.
So I take it your AC control relay is spliced into the ECU control circtuit to ground your relays. The ECU then sees that it's control wires are grounded although it has not commanded them to ground.
http://engine-codes.com/p0480_chevrolet.html
Hopefully someone has experienced this and knows of a fix. I think you could solve this with another relay for isolation, but there may be an easier solution.
07-05-2015, 03:01 PM
#5
TECH Resident
I had this issue or similar. And I think 1964SS nailed it.
What I did is ran parallel fan relays one each ground triggered 1. by the ecu and 2. by a trinary AC pressure switch to run the fan. This trigger would be analogous to your always on fan state when the AC is turned on.
In this configuration.....
Then the computer doesn't t already "see" ground on the fan relay trigger with the AC on since the relays are parallel with separate wiring to each. I use a small bus bar at the fan shroud to tie the outputs from both relays which drive the fan. Of course at times both relays are hot, but the ecu is never back fed ground so no error code.
Another option would be to use a diode to isolate the computer from the other ground trigger.
What I did is ran parallel fan relays one each ground triggered 1. by the ecu and 2. by a trinary AC pressure switch to run the fan. This trigger would be analogous to your always on fan state when the AC is turned on.
In this configuration.....
Then the computer doesn't t already "see" ground on the fan relay trigger with the AC on since the relays are parallel with separate wiring to each. I use a small bus bar at the fan shroud to tie the outputs from both relays which drive the fan. Of course at times both relays are hot, but the ecu is never back fed ground so no error code.
Another option would be to use a diode to isolate the computer from the other ground trigger.