why are trac off and cel lights both on on 1992 Lexus LS400

i had both rear os replaced, do i need to replace front os too

Asked by for the 1992 Lexus LS400
I will be happy to read the fault memory for you. Anything that effects emissions will put the MIL on even a transmission problem. If the tracs lamp is on it may be the reason the MIL is on.