Merc A140 ECU question

It might just be some form of theft protection?

Don't know about Mercs, but VAG engine ECUs are paired with the immobilizer (in the instrument panel), so while removing the ECU and refitting it to the same car is OK, putting it in another won't work.

It's not called the "Book of lies" for nothing. Only NEW ECUs need coding to the car.

If you ever need it fixing - seems to be shockingly common.

W210 ....

There was a time when MB were noted for being bullet proof but that was a long time ago.

The air mass meter is part and parcel of the ECU (yes, crazy design) and often fails. Therefore the new AMM comes with a new ECU which obviously needs pairing with the immob and keys.

Possibly the worst car ever made, both to drive and maintain. Period.

Tim..

Would you have to pay a dealer every time your battery went flat, or when you had to replace it?

oddly enough the idea of that came to me yesterday when I disconnected a battery, it would be trivial to add in some instruction that meant the ecu needed a code if power was lost, just like a radio. and only a dealer with specialised equipment could reset it.

Some early versions of the Rover 820 needed dealer attention to reset the ECU if battery power was lost. Failing to do so would mean an idle that was so poor it would fail an MOT on emissions.

Chris

If that was the case then thats just piss poor design;!...

Merc A140 ECU+MAF seems to have quotes around £1000-£1300. £200+ for your coded ECU repaired. German car, French Valeo electronics. What do they expect? Payback for the crap "frog export" grade stuff that Bosch sold to Citroen for the BX.

Built in message "you WILL scrap this car when it's 12 years old". First battery change at 6-7 years old will get a reset done by a main dealer as the 2nd owner still thinks it's worth the cost and wants to flog it.

Use a power saver keeps the circuitry live whilst battery is being changed

Doesn't help much if you've left your lights on, or the battery fails significantly overnight however.

Chris

Early Single point injection flavour as i recall.

Tim..