Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSAUDI1999A4 BASE, 1.8 B, AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)HEATING, VENTILATION & A/C (HVAC)HVAC CONTROL SYSTEMSA/C-HEATER SYSTEM
1999 Audi A4 Base, 1.8 B, Automatic
A/C-Heater System
1999 Audi A4 Base, 1.8 B, AutomaticSECTION A/C-Heater System
- Specifications
- Description
- Operation
- Self-Diagnostics
- Notes
- Retrieving & Clearing Diagnostic Trouble Codes
- A/C-Heater Control Panel Coding
- Basic Setting
- Measuring Value Block
- Output Diagnostic Test Mode
- DTC 00000: No DTC Recognized
- DTC 00532: Supply Voltage Too Low
- DTC 00600: Temperature Regulator Flap Motor Position Sensor
- DTC 00601: Central Flap Motor Position Sensor
- DTC 00602: FOOTWELL/Defroster Motor Position Sensor
- DTC 00603: FOOTWELL/Defroster Flap Motor
- DTC 00604: Back Pressure Flap Motor Position Sensor
- DTC 00625: Road Speed Signal
- DTC 00779: Outside Air Temperature Sensor
- DTC 00785: Instrument Panel Interior Temperature Sensor
- DTC 00787: Fresh Air Intake Duct Temperature Sensor
- DTC 00792: A/C Pressure Switch
- DTC 00797: Sunlight Photo Sensor
- DTC 01206: Signal For Time Span Ignition Off (Incorrect Signal)
- DTC 01271: Temperature Regulator Flap Motor
- DTC 01272: Central Air Flap Motor
- DTC 01273: Fresh Air Blower
- DTC 01274: Airflow Flap Motor
- DTC 01296: Center Outlet Temperature Sensor
- DTC 01297: Floor Outlet Temperature Sensor
- DTC 65535: A/C Control Head Malfunction
- Testing
- Notes
- A/C System Performance
- Test Equipment Hook-Up
- A/C-Heater Control Panel
- Temperature Sensors
- Fresh Air Blower & Fresh Air Blower Control Module
- Air/Temperature Distribution Flap Motors & Sensors
- A/C Pressure Switch, A/C Compressor Signal, Engine Temp. Signal & Interior Temp. Sensor Fan
- A/C Clutch Relay & Coolant Fan Low Speed
- Removal & Installation
- Notes
- A/C Compressor
- A/C-Heater Assembly
- A/C-Heater Control Panel
- Accumulator
- Air/Temperature Distribution Flap Motors
- Center Console
- Center Outlet & Floor Outlet Temperature Sensors
- Dust/Pollen Filter
- Evaporator
- Fresh Air Blower
- Fresh Air Blower Control Module
- Fresh Air Intake Duct Temp. Sensor
- Heater Core
- Orifice Tube
- Torque Specifications
- Wiring Diagrams
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.