So I find myself with an early A8 4.2 Quattro Sport. It is a bit of a shed, but has MoT, tyres with tread and drives quite nicely. It does have a number of electrical issues, the most serious of which is the airbag light.
It came without a bulb in the warning light. Presumably to fool the MoT man, which shouldn't have worked but apparently did.....
Did a code read with Vagcom and got a small book of fault codes including the "63355" which indicates an ECU fault. The ECU is 8A0 959 655K. I have a spare ECU 8A0 959 655C originally intended for my A6, which also seems to be be sometimes listed for early A8. I plugged it in an it seems to function (even softcode was the same). This got the fault code list down to one item. Drivers side seatbelt tensioner resistance too high. Some testing (2.2 ohm resistor connected in place of the igniter) shows that this does appear to be true. I've now fitted another seat belt assembly and cleared all the codes. Codes stay clear - but the warning light remains on......
I'm now stuck. I could source the correct "K" suffix ECU fairly easily, but not convinced it will make any difference.
Any wisdom on the subject gratefully received!
Also curious to know what differences the final letter on the ECU p/no show. There is a small family of identically dimensioned units with nearly the same VAG p/no and the same plug/pin-outs but with with different Bosch part nos and different suffix letters. There are even a couple of cases where the same VAG part no carries over to more than one Bosch no. I guess it may simply be that the G-sensors have different trigger points for different car weights/crumple characteristic - which would mean you really want the right one in the right car so it triggers when the designers intended......
Damn car may be 20 years old but 'tis still a bit complicated for my little monkey brain.....
Cheers
Nick
It came without a bulb in the warning light. Presumably to fool the MoT man, which shouldn't have worked but apparently did.....
Did a code read with Vagcom and got a small book of fault codes including the "63355" which indicates an ECU fault. The ECU is 8A0 959 655K. I have a spare ECU 8A0 959 655C originally intended for my A6, which also seems to be be sometimes listed for early A8. I plugged it in an it seems to function (even softcode was the same). This got the fault code list down to one item. Drivers side seatbelt tensioner resistance too high. Some testing (2.2 ohm resistor connected in place of the igniter) shows that this does appear to be true. I've now fitted another seat belt assembly and cleared all the codes. Codes stay clear - but the warning light remains on......
I'm now stuck. I could source the correct "K" suffix ECU fairly easily, but not convinced it will make any difference.
Any wisdom on the subject gratefully received!
Also curious to know what differences the final letter on the ECU p/no show. There is a small family of identically dimensioned units with nearly the same VAG p/no and the same plug/pin-outs but with with different Bosch part nos and different suffix letters. There are even a couple of cases where the same VAG part no carries over to more than one Bosch no. I guess it may simply be that the G-sensors have different trigger points for different car weights/crumple characteristic - which would mean you really want the right one in the right car so it triggers when the designers intended......
Damn car may be 20 years old but 'tis still a bit complicated for my little monkey brain.....
Cheers
Nick
