On Board Diagnostic (OBD) Technical Data

On Board Diagnostic (OBD) Technical Data

Memory Permanent memory
Data output "Rapid data transfer" operating mode 1
On Board Diagnostic (OBD) "AC/Heating Electronics" address word 08
Check Control Module Versions Function 01
Check DTC Memory Function 02
Output Diagnostic Test Mode Function 03
Basic Setting Function 04
Erase DTC Memory Function 05
End Output Function 06
Code Control Module Function 07
Read Measuring Value Block Function 08

NOTE:

If a newly installed A/C Control Head -E87- has not been coded or an invalid code has been entered in the A/C Control Head, depending on the -E87 version the old code will be stored or the 00040 (4 cyl. gasoline engine, left hand steering for Rest of World) or "000000" will be stored.

If a new control head is installed and its display panel flashes (for about 2 minutes) when the ignition is switched on, code the A/C control head and carry out basic setting.

While the On Board Diagnostic (OBD) is performed, the control functions of the climate control remain in operation and are not switched off (i.e. the compressor, positioning motors, coolant fans etc. can be activated).

When the OBD is started, the control functions on the climate control are not interrupted, however they will be switched off during the following functions:
- Performing output Diagnostic Test Mode
- Performing basic setting
When selecting other functions the control function remains completely functional.

The A/C Control Head -E87- is no longer connected to terminal "30" of the electrical system. It stores its latest setting when the ignition is switched off and then reactivates it when the ignition is switched on again. On Vehicles starting with model year 2000 the adjustment is assigned to one key.

On vehicles with a sunroof incorporating solar cells, the A/C Control Head -E87- continues to be supplied with power for a certain period of time when the ignition is switched off. This happens via an additional control module. Power must continue to be supplied (via connector -A- terminal 10) so that the air flow flap motor -V71- (which also actuates the recirculated air flap) can move the fresh air/recirculated air flap to it's "fresh air" position if the system was being operated in recirculated air mode when the ignition was switched off.

If the A/C Control Head -E87 continues to function after the ignition has been switched off, check for a short circuit to B+ in the wiring to -E87 (connector -D-, terminal 1).

On vehicles with auxiliary heating (not for US/CDN) power is supplied to the A/C Control Head -E87- (connector -D- terminal -1- with ignition switched off).

The time that has elapsed since the ignition was switched off is calculated by the A/C Control Head -E87- when the ignition is switched back on (time signal is supplied by instrument cluster). If more than 4 hours passed after the ignition is switched off, the current measured values from the outside air temperature sensors are used to represent the current ambient temperature and engine temperature for the purpose of regulating the system. If the "standing time" was less than 4 hours, the current values are calculated by the A/C Control Head -E87- (the heat emitted from the engine and radiator causes incorrect measurements, and therefore the current measurement values from the temperature sensors are suppressed for a predefined time).

The lower of the two values from the outside temperature sensors is used for air conditioning regulation and for the external temperature display.