wennstroma
11-09-2007, 11:52 PM
I am having a problem with my megasquirt 2 daughter card. I am trying to drive a fan relay with the stepper IAC chip.
When I had my car running last, I did not use the IAC chip for anything and never had the 12volt jumper installed to JS9 to power it up. I am now wanting to use it and as soon as I connect S12C to JS9 and power up the megasquirt the IAC chip gets very hot and goes into pwm current limiting mode. It does this even on the stim and even if I have nothing connected to the JS0-JS3 outputs.
I could not find any shorts on the board that could be causing this, so I contacted diyautotune (who I bought daughtercard from) and Matt said that I could send it in and they would see if something was wrong and replace it if it was faulty. He tested it the way I had it hooked up and said that it worked perfectly for him.
I got it back today and it still overheats and wont put out the proper signals. On 2A/2B I get a 5 volt signal that remains steady for a few msecs then goes into pwm for about .5 secs then goes back to 0volts for about 2 seconds and then repeats. On 1A I get a short 12 volt signal that also goes into pwm limiting, on 1B I get a steady 0volt reading.
This does not make sense to me. How I am getting a 5 volt signal off the IAC chip? How is this happening only on my board when there are no shorts on the board, but works fine on someone elses?
Something I noticed today while trying a different code version was the chip would not overheat while the code was being flashed.
I am about to give up and just use a thermal switch in the radiator or something. I also posted this on the msextra board and only got one response that told me to check something I had already stated I checked.
Has anyone had a similar problem? I couldn't find anything like this while searching the ms forums.
Thanks, Aaron
When I had my car running last, I did not use the IAC chip for anything and never had the 12volt jumper installed to JS9 to power it up. I am now wanting to use it and as soon as I connect S12C to JS9 and power up the megasquirt the IAC chip gets very hot and goes into pwm current limiting mode. It does this even on the stim and even if I have nothing connected to the JS0-JS3 outputs.
I could not find any shorts on the board that could be causing this, so I contacted diyautotune (who I bought daughtercard from) and Matt said that I could send it in and they would see if something was wrong and replace it if it was faulty. He tested it the way I had it hooked up and said that it worked perfectly for him.
I got it back today and it still overheats and wont put out the proper signals. On 2A/2B I get a 5 volt signal that remains steady for a few msecs then goes into pwm for about .5 secs then goes back to 0volts for about 2 seconds and then repeats. On 1A I get a short 12 volt signal that also goes into pwm limiting, on 1B I get a steady 0volt reading.
This does not make sense to me. How I am getting a 5 volt signal off the IAC chip? How is this happening only on my board when there are no shorts on the board, but works fine on someone elses?
Something I noticed today while trying a different code version was the chip would not overheat while the code was being flashed.
I am about to give up and just use a thermal switch in the radiator or something. I also posted this on the msextra board and only got one response that told me to check something I had already stated I checked.
Has anyone had a similar problem? I couldn't find anything like this while searching the ms forums.
Thanks, Aaron