Your Lambda reading indicates that the system is in fixed operating mode, and that there's definitely a fault somewhere -- most likely a sensor or short somewhere in the system.
If you have the CD set, it lists the % faults there, but you gotta dig deep. What 103 engine is in the SE? (103.xxx?) I will look it up for you if you have that information.
'01 E430, Sport 72,000 mi
'98 C280, 126,500 mi