Hello All, ECU IG fuse & IG2 fuse block: Putting 12v to it starts dash lights and the lights start blinking But key press doesn't start car Where does the power to the transmission computer come from? HV ECU... no power Transmission ECU... no power ECU IG fuse... no power Can't read codes from the above ECUs, only the body ECU and it gives codes B2287 & B2289. I replaced the PSC ECU and the car started once. Now any replacements don't start the car. Wires and fuses are fine. Relays may all be fine. They work and were checked and swapped and still work.
Where does the power to the transmission computer come from? A fuse under the hood. I went through similar and replaced the powertrain control module (next to the engine ecu behind glovebox) only to find a road salt destroyed fuse that went to the ptcm In my case there were no codes, no ready, shifting it placed it in nuetral only.
Thank you @tracy ing . If I unplug every ECU near the dash/driver side/passenger side so that means the Transmission, Gateway, HV Control, Power Source, Smart Key, etc and then plug them all back in the car starts and will go into ready. Addition: I don't have to press the "Start" button after plugging in the last ECU. The car just jolts on after the last ECU is plugged in. Then, if it sits off overnight, I can't turn on the car anymore.
Also, if I'm using Techstream to read codes after an overnight period where in the morning the car doesn't start, I'll do a health check and only get some ECUs. If I unplug an ECU that doesn't show up and then plug it back in and then do another health check then that ECU will show up. So the ECU show up once plugged in and unplugged.
Are you plugging them in with the low voltage battery connected to the car ? If so, probably shouldn't be doing that. Aside from possibly damaging something, i would think that would create codes as this doesn't see that on unit boot up
If you handed me that car, the first thing I would do is use the CHEAT to reprogram any new devices, like when I added that EBAY powertrain control module, that would not work because the car didn't recognize it, authorize it. I dont remember the exact process, but is starts with, get a good car battery and jump it to your battery to your battery does not die during the process. (a battery charger may add problems so I use a good big battery). Then you do the process which I think was press Power and walk away for 30 minutes, someone here can correct me and tell you the right way. I would do this first because I don't know what is going on in the car at this point and I want to discount this as an issue with any replaced electronics. Before I did that, I would try to find every connector someone may have fiddled with an unplug and reseat them, with the low voltage disconnected. And before I did that, I would check every fuse in the car lol.
