Contrary to public belief, your MBZ E320's check engine light being
illuminated anytime during the smog inspection is automatically a smog
failure, whether engine or transmission related. Vehicle manufacturers have
placed the Check Engine light inside the passenger compartment to inform the
driver there has been or is an engine or transmission malfunction. Very
often you may not notice this problem, but this is only because your
engine's computer is operating under pre-programmed information rather then
of real-time. In other words the problem still exists but your vehicle
"learns to live with it".
Transmission related trouble codes do in fact cause smog check failures.
More then often a defective transmission component will effect overall
engine performance and emissions.
According to our Emission Application Guides Digital Trouble Code P1711 for
your 1996 Mercedes Benz Model E320 indicates that the P1711 code is
"Electrical Activation of Resonance Intake Manifold Switchover Valve". This
fault is not transmission related, and needs to be diagnosed by an expert
smog check repair center, or a Mercedes Benz dealer. There is a brittle air
tube which leads to the Switchover Valve that may be broken or disconnected.
