Diagnostic Methods

FAULT DIAGNOSIS HINTS
When taking readings and carrying out fault diagnosis, the connector must be unplugged. All readings must be taken on the connector and not on the climate control unit. With the exception of changing bulbs, the unit must not be tampered with in any way.

Self-Diagnostics
There is a special self-test program in the climate control unit's microprocessor.

The program checks certain functions at regular intervals while the car is being driven and an emergency mode will be activated if a fault develops in any of the sensors. Faults detected by the self-diagnostics program are stored as diagnostic trouble codes in the microprocessor's memory. Readouts of diagnostic trouble codes are obtained with an ISAT scan tool.

Calibration
The flap actuator motors must be calibrated at the following times:
^ After changing the control panel.
^ After changing the flap motors.
^ If the battery is disconnected within 30 seconds of the ignition having been switched off.
^ If the battery has been fully discharged or if battery positive voltage has been higher than 16 V.

Calibration is carried out either by pressing the AUTO and VENT buttons simultaneously or by means of an ISAT scan tool.

A self-test is carried out in conjunction with calibration. The total time for calibration and self-testing is 22-50 seconds. The number of faults (0-5), if any, is shown in the display during the first 35 seconds.

Other Fault Diagnosis
1. Check that the relevant fuses are intact and supplied with current.
2. Check the interior temperature sensor's suction fan by allowing a thin piece of paper to be sucked onto the intake.
3. Check the climate control unit connectors. Clean them by unplugging and plugging them in again.
4. Check the wiring harness, connectors and ground connections. For checking A/C compressors and radiator fans, refer to Air Conditioning, A/C.