thought I would let everyone know of result,,, purchased lhs cat ecu, from sytner ferrari in edinburgh, £151 inc vat,, fitted part,, switched engine on,, and slow down light still on,,, switched power to car off in the front boot, left for ten minutes,, started engine and let sit for ten minutes idling as required, but slow down light still on from cold,, decided this afternoon as home early to pop along to one of the local specialist, to see if he can check codes or reset light,,,,,, got outside his garage, light was still flashing but dim,, switched engine off,,, switched engine back on,, and hey presto,, light has disappeared,,,,, so it was the cat ecu,,, and the seemingly the lights should reset themselves to off,, but will leave error message on main ecu which can be checked and cleared at next service,,,, it took about 5 miles for the light to effectively reset itself,,, sigh of relief ! thanks for all the replys and help scottie
Let me be the first to say I was wrong about the light not going off by itself then! i don't own a 355, i just work on 'em. Seems that I am going to have to do more "test driving" to clear the lights I will bet that a code is still in the main ECU, and will be untill it is cleared, just waiting to annoy the next person to pull codes from your car.... No experience with the scanner you mentioned, so no comment. E
the LH ECU (the old one) did have continuity between one of the top and one of the bottom contacts,, (i,e) closed circuit inside,,, both the RH and the new ecu did not have continuity... its also worthwhile noting that, if you check the resistance on the the out put leads from the thermocouple, you get compariable readings,,,, checked it cold and then while the cats were heating up and got similar readings from both,,,, so that should be a foolproof way of checking the thermocouples in future. scottie
out of interest,,,, my wifes car (vauxhaul), when picked up after service,, still had the service light on,, they told me it owuld go out after a few miles,,, funnily enough it did,, only remembered about that after the ferrari one went out !,,,, but yes,,, the code will still be stored in the main ecu,, and will need reset during next service,, or if I buy a scanner scottie.
Well one way to clear the codes is to disconnect the battery. At least that's how it works on 348's. Unless the ecu's have a sperate power source disconnecting the batery should clear out the codes. Kind of like when you disconnect the battery and all the prset radio staions need to be reprogramed, and the clock reset. So you may want to try that. But be sure to let your car go through the full warmup process so the ecu's can relearn the process. If you don't the car will idle rough, and possibly die in stop and go traffic.
Depends if the ECU uses battery backup, flash memory or an E2PROM of some kind - but worth a try. Mind you, wont know if its worked until you plug a tester in anyway, which can clear the code at same time lol.
