The On Board Diagnostics System, 2nd generation has been imposed by law. Guess who enforced this first...
Every default codes are stocked in memory during 40 cycles. A cycle is defined by the coolant going from 16°C to at least 70°C and back. This means every default code is stocked for 40 cycles after it last occured. The data can be worked on by the TestBook. The OBDII also activates the MIL-light (US-only). If the light goes on and no error code is in memory the automatic transmission gave the signal. However not EVERY default signal is stocked. Due to the great amount of data flow it takes a varying amount of errors to trigger the default code.
You can read the diagnostic codes of the Air Condition when you push at the same time the "MODE" and "AUTO" buttons and keep them pushed. All the codes are then shown one after the other in the temperature indication field . Code 21 and 22 will disappear when you turn the ignition key to position II and put the vehicle in bright light.
| Code | From | Showing |
| 00 | Normal | |
| 11 | Int. sensor | open circuit, short or 12 Volt connection |
| 12 | Inside temp. sensor | open circuit, short or 12 Volt connection |
| 13 | Evaporator sensor | open circuit, short or 12 Volt connection |
| 14 | Water temp. sensor | open circuit, short or 12 Volt connection |
| 21 | Left solar sensor | open circuit, short to - or 12 Volt connection |
| 22 | Righ solar sensor | open circuit, short to - or 12 Volt connection |
| 31 | Potentiometer or electric motor for left side air duct | Open, short to 12V or to -, blocked motor |
| 32 | id. for right side | Open, short to 12V or to -, blocked motor |
| 33 | Mode potentiometer or mode electric motor | Open, short to 12V or to -, blocked motor |