acert serial numbers

usually on the passenger side of block about top of frame level 6inches from the back of block. if the cam sensor is behind air compressor and not on side of front engine cover it is a bxs. it takes a 70 pin ecm for that configuration but not like what is on the other mbn's, 6nz's or older. the 70 pin ecm for the bxs is built specific for the bxs. they look the same but are a different breed. the newer a-certs mxs and nxs use the 120 pin ecm's. there might be someone else on here that knows where else to look on block that will be along shortly.

 

that 98 w900 should had 3406E. The serial number can be anywhere. They usually of the right like superhauler said.

 

you mean mxs, that is fine if it is that series of a-cert. but if it is a bxs a-cert that mxs serial# wont work.

 

Passenger side of engine. Towards the rear of engine block. Just above the oil galley. Grind the paint and rust off. S/N starts and ends with a * symbol. Newer engines, the numbers will be a dotted number stamp style. Good luck. The engine S/N will allow the dealership to look up the 'as shipped' parts list. Which will include the ECM software part number.