General Information

Erasing DTC memory
The DTC memory can only be erased with the Hand-Held Tester or the generic scan tool. This will also erase any freeze frame data. After erasing, disconnect the Hand-Held Tester or the generic scan tool (or give the "end" command) and turn the ignition switch off for approx. 5 seconds, so that the DTC memory can be overwritten. If the DTC memory was erased, the memory storage enablement (see definition below) must be reactivated by running through the corresponding number of "performed" tests or "trips" for a particular renewed failure recognition and corresponding activation of the "CHECK ENGINE" MIL.

Repair note:
In compliance with a SAE communication standard, freeze frame data is associated with the fault which first required the "CHECK ENGINE" MIL to be turned on. No subsequent freeze frame data is stored.

Definition: Memory Storage Enablement
Certain failure path tests and logic chains must be performed completely at least once between turning on the ignition and turning the ignition off (one operating cycle). Therefore, two "performed" tests can only be obtained in two operating cycles.
Operating cycle (USA) version only
One operating cycle is reached if:
- Engine coolant temperature > 60° C
- Engine rpm for 5 seconds at 2500 rpm
- Ignition OFF for 5 seconds
- Engine rpm for 5 seconds at 2500 rpm
- Ignition OFF for 5 seconds
- Engine rpm for 5 seconds at 2500 rpm

See HHT menu 3/8 Memory storage enablement OBD II