MODEL IDENTIFICATION
| Model Year | Models Covered |
|---|---|
| 1998-2004 | A6 |
| 2001-2005 | Allroad |
| 2002-2003 | S6 |
| 2003 | RS6 |
MODEL IDENTIFICATION
A6, Allroad, RS6 and S6 models are equipped with one of several brake systems. Brake caliper application is designated by the Production Code (Pr. No.). Pr. No. is printed on vehicle data sticker located in spare tire well or in owners customer's service schedule. (Scheme 1) For brake caliper Pr. Nos., see PRODUCTION CODES table. To identify brake system and components (Scheme 2)- (Scheme 7).
| Brake System | Production Number | ||
|---|---|---|---|
| Front | |||
| FN3 | |||
| With 15" Wheels | 1LB/1LE | ||
| With 16" Wheels | 1LT/1LF | ||
| FNR-G60 | 1LA/1LG | ||
| HP 2 | 1LX/T7Z | ||
| Brembo | 1LJ | ||
| Rear | |||
| C38 | 1KD | ||
| C43 | 1KE/1KZ | ||
PRODUCTION CODES
Scheme 1
Scheme 2
Scheme 3
Scheme 4
Scheme 5
Scheme 6
Scheme 7
DESCRIPTION & OPERATION
All models have self-adjusting front and rear disc brakes. The cable actuated parking brake mechanically activates the rear calipers.
Hydraulic system uses a tandem master cylinder with vacuum assist. Hydraulic system is diagonally split. Left front and right rear wheels form one circuit. Right front and left rear wheels form the other circuit. The brake pressure regulator has been deleted, as regulation function has been replaced by ABS control module programming.
Turbocharged models are equipped with an auxiliary electric vacuum pump. Vacuum pump supplies vacuum to power booster ensuring adequate vacuum for proper vacuum assist. Vacuum pump is activated by vacuum sensor signal to ABS control module. Vacuum sensor is located in power booster vacuum line.
Description & Function
The electric vacuum pump is only installed in vehicles with automatic transmission. It is switched on by Engine Control Module (ECM) depending on intake manifold pressure. Vacuum pump is On Board Diagnostic (OBD) capable. Detected malfunctions are stored in Engine Control Module (ECM) memory. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. Testing function of electric vacuum pump via On Board Diagnostic (OBD) must only be performed with engine at standstill.