200tq check engine light, but no codes!?

[Phil Payne]

> Well ... tried your technique today ... and sure enough I did get an
> error code to flash out. It's 2113 which indicates a problem with the
> Hall Sender.
>
> The MAC-14 computer on the '90 200tq model DOES have permanent fault
> memory, but I don't know why this fault wasn't registering before.
> http://www.sjmautotechnik.com/ecuf_MC2.html#fctwo

I've got an experimental SJM ECU in my Type 44 - it produces a short flash whenever knock is
detected and a long flash when a code is stored.  But I've noticed that _some_ codes - or
rather some instances of some codes - are not preserved across a power cycle.  Some are - I
don't know what the rules are.

Also I've seen cars where the immobiliser installers have found "a wire to the ECU" and have
cut it with their box - not realising they were cutting the memory power and not the operating
power.

If your alarm/immobiliser has a key to disable it, do this while debugging.

--
  Phil Payne
  http://www.isham-research.com
  +44 7785 302 803