Thursday, December 1, 2011
Audi A6 C5 Air Conditioner Output Diagnostic Testing
Component location of activated components, The Output Diagnostic Test Mode (DTM) can be carried out more than once if necessary. If components marked with an * malfunction, DTCs for these components can be stored in DTC memory. Checking the “Idle Air Control” (IAC) regulation function. During output DTM, the vehicle must not be moved and the engine speed must be lower than 3000 RPM. During output DTM, the air conditioning control functions are switched off. Depending on A/C Control Head -E87- version, all segments, control lights in buttons as well as the button illumination of - E87- are displayed or dark. For Audi allroad, the change-over of the A/C system is not performed with the model year change 2001 to 2002, instead it is a running change (implementation open, for vehicles with 4.2 Liter engine with start of production). A/C clutch -N25- - A/C clutch -N25- clicks every 2 seconds, compressor is engaged. - Input of A/C Control Head -E87- is closed every 2 seconds (switched to Ground). - Check voltage supply for A/C clutch - N25- (via clutch relay -J44-) according to wiring diagram. - Check wiring between -E87-, -J44- and -N25- according to wiring diagram. - Replace A/C control head - E87-. The ECM uses the A/C compressor cut in signal to compensate for the temporarily higher load placed on the engine when the compressor is switched on. The ECM can switch off the A/C compressor via the A/C compressor cut-in output/input ( Read measuring value block). Fresh Air Blower -V2- - Fresh Air Blower -V2 is activated for 2 sec. with 0V, 3V, 6V, 9V, 12V, 15V, 0V etc. - Make sure fresh air blower moves freely. - Check Ground connection to Control module for fresh air blower -J126- according to wiring diagram. - Check control module for fresh air blower - J126- - Replace A/C control head - E87-. Actuator for temperature flap left -V158- - Actuator for temperature flap left - V158- moves from stop to stop (fresh air blower is running and air is coming from instrument panel vents) 1). - Air temperatures from left vents changes. - Check wiring between Actuator for temperature flap left -V158- and A/C control head -E87- for open circuit or reversed wiring according to wiring diagram.
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