Have a 1990 Bonneville le pulled codes and got 24 27 28 29 and 31. 24 is vss but the speedometer works. 31 is park neutral switch I think and the car starts in park. Wondering if maybe ecm bad all seem to be transmission free but transmission feels fine any help would be appreciated thanks.

24 vehicle speed (vss) sensor circuit fault
27 quad-driver module (computer) 2nd gear circuit
28 quad-driver module (computer) circuit #2 fault
29 quad driver module (computer) 4th gear circuit
31 cam position sensor fault

so the car is running fine and you got all these codes?

i would be looking for wires shorted to ground on the engine wiring harness, especially the harness that goes to the trans

Yea car runs fine took the transmission vacuum modulator off this morning transmission fluid came out replaced with a new one. Replaced a few air line couplings that were dry rotted. Unplugged the wire harness from the transmission cleaned it added dielectric grease. Reset so no codes took car for drive going though all gears came home checked for codes and there were none. I don't know something I will keep monitoring the situation the next couple of days to see if codes come back.

keep us posted

OK got code 31 again. What'* the differnce between code 31 cam position sensor fault and code 41 came sensor. I've read a bunch of threads with people with code 41 for cam sensor.

41 is listed as the circuit fault and 31 is listed as sensor fault