1992 300CE CEL - pulls code 11

[tcb323]

Hi,

on my 1992 300ce M104, 150k, CEL trips and i retrieve code 11 from led under hood.

reset twice and comes back with in 2 days each time. no pattern to it coming back, no other symptoms.

where do i go to troubleshoot, dont have manual. can you help me?

thanks!
joe
LA

[esanding]

code 11 its air injection system ,, check vacuum hose before and after the solenoid and also the check valve use a vacuum pump tester.....