Preconditions for the test:
Engine running.
No faults stored.
All electrical loads switched off.
Gear selector set to P/N.
Induction air temperature below 60 °C.
No leaks in the exhaust system.
Note:
For diagnosis of catalytic converter efficiency.
This diagnosis is initiated only when the lambda probes have been tested and are OK.
Procedure:
Choose the function: Catalytic converter diagnosis.
Press and hold down the brake pedal. Within a few seconds the engine control unit will raise the engine speed to increased idling.
The temperature of the catalytic converter must be above 400 °C.
The diagnostic status field changes from ”Test off” to ”Test on”.
Maintain the engine speed until the diagnostic status field changes from ”Test on” to ”Cat B1 OK! / Cat B1 not OK!”.
Read the amplitude. Prescribed value max. 0.50.