Jim Grant's Tech Tips
Lincoln Town Car, Check Engine Light on Again
have a '94 Lincoln Town Car. The "Check Engine Light" comes
on. The car was diagnosed as needing an EGR valve. The valve was replaced
but the "Check Engine Light" still comes back on. Is it a possible
the EGR valve replaced because the computer had a code for the EGR system?
Or, was it diagnosed "proving" that the EGR valve was needed?
There are several components, some related and some not, to the EGR system
that can cause the vehicle's computer to turn on the "Check Engine
Light" and set a code for the EGR system. Basing repairs (replacing
parts) on a code provided by a vehicle's computer and not by diagnosis
often leads one right back where they started. The only way you will know
is to ask the vehicle's computer why the "Check Engine Light"
is on again.