I have a 1991 300CE-24 Sportline with Bosch KE Jetronic (CIS) injection and 5-speed 722.5 auto box. 350 K Kms on the clock.

I built a code reader (count the flashes, not too sophisticated!) and this enabled me to erase a gearbox fault that had put the 'box into some sort of safe mode. It's now performing as it should be with all 5 gears. Component cost of reader: €15.

I read the codes from the 16-pin (4 mm sockets) diagnostic connector close to the battery. Oddly, I've seem more information on the socket related to W129 cars than W124. Nonetheless, it is installed on a limited range of W124 cars.

I shall use the same reader to examine engine issues, possibly this weekend, weather permitting.

More as it happens.

RayH