1999 C70 Code 720A Immobilizer signal missing

[EmmanuelMedina]

Hello guys, So the other day I knocked off one of my front turn signal light coverings. in a haste I removed the covering and light bulb without unplugging my battery (it was also raining) when I plugged it back in the car fired up but died right away. I checked the fuses and the fuse for the control panel/dash board was blown I replaced it but the car would not turn on> it cranks but does not turn over at all. I plugged my alter scanner and the only code it gave me is the 720A 720A Immobilizer signal missing. Im assuming I must have created a fault and that blew the fuse, does anyone know where I should go from here? any relays associated with the immobilizer unit or other fuses I should check as well as any connections? thank you guys for all you're help.

[xanthefin]

When you turn Ignition ECM sends QUEST.REC message to Immo to wake it up and to get response to secret handshake to validate all is okay with IMMO.

You are mostly missing this which why you get the fault code code.

If you cant connect to IMMO.
Check its fuses

Its the Fuse box (11C) near windscreen under a bonnet.. not in da hood like in 'murica.

#8 and #4 Fuses.


If they are fine and still propably you need locate IMMO box and just try take it out and put it back in connector if there lack of electricity after decades makes slight corrosion. Its located your steering column so need crawl at driver side foot area to see it after removing plastic.


If no then you need look live data of IMMO (if you can connect to it with devices you have, cheapest is ELM327 and App) to further diagnostics.