Hi
Just wanted to share this nightmare with you all, had Mass airflow sensor go and had that changed with genuine part, £400 including labour, then after a week car went into get me home mode, returned to garage and they reset, 1 month on car started drove fine then stopped, lights flashing on dashboard, switched off car, would not start again, took it to garage they replace the ignition unit £300 plus programme key (refundable £150.00) car would still not start, ended up taking to main dealer to have the Merc diagnostic tool to check out all faults £200, A nightmare scenario, to add insult to injury the main dealer suggest to me that the fault was not the ignition switch but a bad fuse which upset the Immobiliser etc.

Just wanted to post to say learn by my mistake and check all fuses (if you can find them) before you spring for big money.

Go well.

Broke from Devon, UK