Here is the tutorial with component identification for UCH N1 / N2 / N3 based on repair experience with these units.
internal electronic fault. Also dead immo light (never lights), cranks, no start
or interior light always on ( in dashboard door open signal always on)
or immo light not flash (not at all) on dashboard and the car not crank at all.
1 – Check for all marqued diodes (cold joints, burned diodes, etc)
these are simple 2A SMD diodes like 1N400x series but rated at 2 amps
2 – Check for solders on the 40 pin black connector (reverse side)
3 – Check marked power supply capacitor as well its diode and 5V regulator IC (TLE4269)
4 – Very important resolder each Array IC ULN2003 ( can be other reference)
5 – Very Very important Resolder MCU / CPU with hot air or a very small iron tip with flux. Remind you this is a dangerous step as pins could solder each other! Use a magnify tool to check and re-check!
6 – Search for other cold joint over the main board
PS – We’ve repaired dozens of these units without replacing one relay. they appear to be very solid and reliable. They use a very new design since 2006. Latest UCH units are very reliable. you identify them as they are sprayed with varnish. New UCH units Clio 3 and Clio 4 don’t suffer this problem. But a simple resolder on these will solve many many problems.
Some people remove also 40 pin connector (not recommended for those that don’t have knowledge of microsolder) and resolding all smd resistance and condensers. They are behind this connector.
To remove it you can use big hotgun, but you need practice. Cheers.
Hope it helps. You are at your risk.
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