1999 Audi A6 C5 Service and Repair Manual

This 1999 Audi A6 C5 Service and Repair Manual Covers

Engine & Drivetrain

• 1.8L Turbo petrol engine service and repair (selected markets)
• 2.4L V6 petrol engine servicing
• 2.7L Bi-Turbo V6 petrol engine servicing
• 2.8L V6 petrol engine servicing
• 4.2L V8 petrol engine servicing (selected quattro models)
• 1.9L TDI turbo diesel engine servicing
• 2.5L TDI V6 turbo diesel engine servicing
• Fuel injection and ignition system diagnostics
• Turbocharger diagnostics (turbocharged models)
• Engine cooling system servicing
• Engine lubrication system repairs
• Exhaust and emissions control system diagnostics
• 5-speed and 6-speed manual transmission servicing
• 4-speed automatic transmission servicing (selected markets)
• 5-speed Tiptronic automatic transmission diagnostics and repair
• quattro permanent all-wheel drive system servicing
• Torsen centre differential, propeller shaft, rear differential, and CV joint repairs

Braking Systems

• Hydraulic brake system servicing
• Anti-lock Braking System (ABS) diagnostics
• Electronic Differential Lock (EDL) diagnostics
• Electronic Stability Program (ESP) diagnostics (where equipped)
• Brake Assist system diagnostics
• Brake pad, brake disc, and caliper replacement procedures
• Brake hydraulic system bleeding

Chassis & Suspension

• Front four-link suspension repairs
• Rear multi-link suspension servicing
• Standard and Sport suspension servicing
• Power steering system diagnostics
• Wheel alignment specifications
• Wheel bearing replacement procedures
• Suspension component inspection and troubleshooting

Electrical & Wiring

• Complete factory wiring diagrams
• Battery, charging, and starting system diagnostics
• CAN Bus communication diagnostics
• Instrument cluster diagnostics
• Engine and transmission control module diagnostics
• Climate control module diagnostics
• Symphony and Concert audio system diagnostics
• CD changer diagnostics (where equipped)
• Halogen and Xenon headlamp diagnostics (where equipped)

Air Conditioning & HVAC

• Automatic climate control diagnostics
• Air conditioning compressor servicing
• Refrigerant recovery and recharge procedures
• HVAC control module diagnostics
• Cabin temperature sensor testing
• Heating and ventilation system repairs

Body & Interior

• Interior trim removal and installation
• Dashboard servicing procedures
• Sedan and Avant body repair procedures
• Door lock and central locking system repairs
• Power window regulator servicing
• Exterior lighting system servicing
• Airbag and occupant restraint system diagnostics
• Electrically adjustable and heated seat repairs (where equipped)
• Sunroof diagnostics and servicing (where equipped)
• Body panel alignment and repair information

Driver Assistance Systems

Available equipment varies by market and trim level.

• Cruise control diagnostics
• Parking distance control diagnostics (where equipped)
• Headlamp levelling system diagnostics (where equipped)
• Rain sensor diagnostics (where equipped)

Diagnostics & Troubleshooting

• VAS factory diagnostic procedures
• Guided fault-finding routines
• Diagnostic Trouble Code (DTC) lookup procedures
• ECU coding and adaptation procedures
• Sensor and actuator testing
• Component testing specifications
• Step-by-step troubleshooting workflows

Common Error Codes Covered

This manual includes diagnostic procedures for common Audi fault codes applicable to the 1999 Audi A6 C5.

Engine Codes

• P0102 – Mass Air Flow (MAF) Circuit Low Input
• P0171 – System Too Lean (Bank 1)
• P0300 – Random/Multiple Cylinder Misfire Detected
• P0420 – Catalyst System Efficiency Below Threshold
• P1557 – Charge Pressure Control: Positive Deviation (Turbocharged models)

Transmission Codes

• P0705 – Transmission Range Sensor Circuit Malfunction
• P0730 – Incorrect Gear Ratio
• P0741 – Torque Converter Clutch Performance
• P1757 – Transmission Output Speed Sensor Fault

ABS & Chassis Codes

• C0035 – Left Front Wheel Speed Sensor Fault
• C1140 – Steering Angle Sensor Fault
• C1237 – Hydraulic Brake Pressure Sensor Fault

Network Communication Codes

• U1000 – CAN Communication Malfunction
• U0155 – Lost Communication with Instrument Cluster

Body Control Codes

• B1000 – Control Module Memory Error
• B1225 – Central Locking System Fault
• B1302 – Interior Lighting Circuit Fault

The manual also includes hundreds of manufacturer-specific diagnostic trouble codes, factory wiring diagrams, ECU coding procedures, guided diagnostics, component testing specifications, and repair instructions.

Who Is This Manual For?

• Professional automotive workshops
• Audi dealership technicians
• Independent repair garages
• Mobile mechanics
• Automotive engineering students
• DIY enthusiasts

If you are servicing, maintaining, diagnosing, or repairing a 1999 Audi A6 C5, this factory workshop manual provides the detailed repair procedures, wiring diagrams, technical specifications, diagnostic information, and repair procedures required to maintain the vehicle to Audi factory standards.