I am unaware of what the "TCV" light is...not shown in the 2005 KJ Service Manual... but there is a red LED on the left side of the cluster between the fuel gauge and speedo which is for the SKIS anti-theft system.
Normally this LED lights up for a few seconds after ignition is turned ON then if the ECU is happy with the code received from the chipped key the LED will go out.
If the lamp flashes continuously it means that the ECU was not happy with the chip code sent to it by the SKIM sensor on top of the steering column with a wire surrounding the key entrance. Motor will start and run for about 10 seconds then cut out.
If the LED stays ON all the time without flashing then the ECU was happy with the chipped code it received but did not receive confirmation from the ASD relay that it...the ASD relay...had energized. Motor will turn over but not fire. I had this problem due to a broken wire going to the ASD relay preventing it from energizing.
I could get the engine to run by removing the ASD relay and jumping pins 30 and 87 together inside the empty relay socket until I could track down the broken wire. This will not work if you have flashing red LED so thieves cannot hotwire the Jeep this way if the correct SKIS code is not received.
Have you checked all the fuses...under the hood and inside the cabin?
A battery fitted with wrong polarity often blows diodes inside the alternator and could blow the "fusable link" which is the thick cable going from the alternator to the battery but then you would get the battery icon showing that no charging is happening.
When the new ECU was programmed the correct SKIS code should have been entered.
If the SKIM module on top of the steering column blows then it has to be replaced with a new virgin module from the Dealers and the Dealers have to re-program it to match the chipped keys code....an old SKIM module from a Breaker Yard cannot be re-programmed.
