My conversion is failing emissions because of the following codes:
• DTC P0480 Cooling Fan Relay 1 Control Circuit
• DTC P0481 Cooling Fan Relay 2 Control Circuit
I am not using the ECM to control the fans. I purchased a stand-alone fan set-up that uses it's own thermostat to control the fan. My wiring harness has two wires to control the fans. "Fan high output for relay" and "Fan low output for relay" but they are not being used which is probably the cause of the codes. Can these be shut down with HP Tuners? Any other solutions?

 

Wow, they are failing your inspection for fan control codes? I'm glad I don't have to worry about that stuff here.

The way I see it, you have two options:
1. Use HP Tuners (or similar) to disable those two codes.
2. Install a pair of relays for those two wires to control and don't connect the relays to anything. Honestly a resistor may work too, but I don't know.

If you have a copy of HP Tuners, I could explain how to disable the codes if you're interested. I happen to like running the fan(s) from the PCM, it gives me full control of when they go on and off and it's free. External sensors are one more expense and an additional point of failure in my eyes.

 

Unfortunately, they fail for any code that trips the "Check Engine" light. Which really sucks. I do have HP Tuners but I don't have credits for the particular ECM that's in my truck. It got purchased as a package deal with the wiring harness.

Being a "ECM controlled engine" newbie, I wish I knew how to take the existing set up and utilize the PCM to control it. You're relay idea is interesting....but it doesn't sound like there is much more involved just going the extra mile to control the fans.

 

Since you have HP Tuners software that will be the simpler, faster and neater looking route. I can have the settings changed in the PCM faster than I could neatly wire up and install a pair of relays I already own using materials already in my toolbox.

I don't know how much you know about HP Tuners, so I'll be super basic:

• Connect your laptop to the vehicle and read the VCM (HP Tuners' site has a FAQ about how to do this).
• When prompted, save the file in a location with a name that will make sense to you later (I usually have the date incorporated and end with "read" if it was just a read before some mods or "original" if it is my first read from that vehicle. This way I know that I have a running last known good so to speak). Do NOT edit this file. This is your emergency holy cow, my car won't work properly go back to square one file.
• License the VCM (do single).
• Within the editor go to "File, Save as" and save a copy with the same name but without the "original" tag. This creates a copy of the file you just read on your drive in the same location. We will do all our edits to the new file without the "original" tag. Always do this each time before you modify something.
• Go to the "Engine Diagnostics" window and choose the "DTC's" tab.
• The codes are in numerical order, scroll down until you find the ones you need (about 1/3 of the way).
• Remove the "SES Enable" check box from the code and change the "Error Mode" to "3-No Error Reported."
• Save the edited file with a different name.
• Upload the file to the VCM and turn off the ignition for 30 seconds. Start the car and scan for codes.
• Pass your inspection and drive happy.

Since we all know what images are worth...

 

Go fast. Thank you very much for the useful information. Unfortunately, I do not have an HP Tuner kit. Definitely something I desire for the future but don't have one right now. I am hoping to find someone local who can do what you have described above. My ECM is super accessible so this should be easy if I can find someone.

 

That's really cool. So basically, you're telling the program to ignore that message (to not report it as a fault)?

I'm very much a newbie. I just picked a GTO LS2 dropout today. I'm still on a hunt for a car to swap it into. Current Performance is just a few minutes from my home, so I guess I'll go speak with them when the time comes. I would imagine you'd have to do a number of swaps or a lot of tuning to justify the purchase of this software?

Tipsy

 

No worries, I thought you had access to the software. I must have misunderstood. At least the information is out there for anyone else who may have a similar question.

Yes, depending on the settings you can say if it enables the SES light and / or if it even sets a code. There are tons things you can disable, and other parameters you can adjust according to your setup and needs.

You don't have to do "a number of swaps" to make it worthwhile, but it all depends on what you value as "worthwhile." I bought the software after I got my first LSx swap running because I felt the car had more in it - and I was right. I had read a lot about the software and what you can modify but didn't realize the breadth of things it covers. There are more parameters available to adjust than you would think of just sitting around with friends. Granted this isn't "easy" software to learn but if you are a technical minded person who likes to understand evrything it may be a good investment.

To put the value in perspective...
HP Tuners has the ability to adjust any parameter that controls engine idle, spark, part and full throttle, light cruise, shift points, enable or disable security, change gear ratios, remove speed limiters, etc., etc., etc. If that isn't enough you can data log and scan / reset codes. I own several cars I can use the software on, but even when I didn't I used it all the time to log, adjust and learn about my car. It's all perspective... Do you want (or need) a home vacuum with a hose attachment or do you want (or need) a shop vac? Even though you aren't going to do tons of cars, it may be a good investment but that is a call you will have to make.

Granted all my talk is about HP Tuners because I own a copy. EFI Live is a competing product, however I found the initial purchase and future license price slightly higher. Coupled with the application's interface being "less friendly" than HP Tuners to how my brain works I chose the one I felt more comfortable owning. It has been a very worthwhile investment.

 

Good food for thought.

Thanks.

Tipsy

 

Fans circuits enabled. No "check engine" light. Passed emissions. One happy guy!!