A) Clogged fuel filter B) Vacuum leak C) Weak fuel pump D) Restricted exhaust

C) Replace ignition coil cylinder 2

A) Failed catalytic converter B) Aging upstream O2 sensor C) Exhaust leak before upstream sensor D) Rich fuel mixture

Correction : Let’s stick to exam logic – high NOx + slow upstream switching + steady downstream at 0.7V = upstream sensor lazy, causing converter to run inefficiently, but converter not failed because downstream is steady. Answer = B. Question: DTC P0011 (Camshaft Position A – Timing Over-Advanced or System Performance Bank 1) is set on a VVT engine. At idle, the commanded intake cam angle is 0°, but actual is 15° advanced. Oil level and pressure are normal. What is the most likely fault?

A) Camshaft position sensor B) VVT solenoid stuck open C) Timing chain slipped D) Low oil viscosity