Generators & Regulators: Other — Audi A4 B5 facelift (1999-2001)

Generators & Regulators: Other Audi A4 B5 facelift

Charging System 1 illustration ~658 words

BELT TENSION

Engines are equipped with a serpentine belt. Belt adjustment is not necessary.

Disconnect Blue (D+) wire from generator. Connect jumper wire between Blue wire and ground. Turn ignition on. If indicator light does not come on, go to step 3 . If indicator light comes on, go to next step.
Check for poor generator ground and worn brushes. If generator ground and brushes are okay, replace voltage regulator. If light still does not come on, replace generator.
Disconnect negative battery cable. Replace indicator light bulb and reconnect negative battery cable. If indicator light still does not come on, repair circuit between generator and indicator light.

Defective generator diode and/or rectifier bridge. Replace generator.

Check drive belt tension. If tension is okay, disconnect Blue (D+) wire from generator. Turn ignition on.
If indicator light does not come on, perform «GENERATOR OUTPUT TEST»(ref-4188-S26495520672000061500000) under ON-VEHICLE TESTING. If indicator light comes on, check for short to ground in Blue wire between generator and indicator light. If Blue wire is not shorted to ground, replace generator.

Ensure connections at battery, generator, and starter are clean and tight. Ensure generator, engine, and body are properly grounded. Ensure drive belt is adjusted and in good condition.
Connect charging/starting system tester according to manufacturer's instructions. Operate engine at 2000 RPM. Generator output should be 90-110 amps.
If generator output is low, repair or replace generator. If reading is 16-20 amps less than generator rating, replace regulator. If output is still low, repair or replace generator.

Set ohmmeter on 100x scale. Connect ohmmeter leads between generator output terminal and each 3 stator terminals, in turn. (Scheme 6) Reverse ohmmeter leads. If ohmmeter indicates continuity in only one direction, go to next step. If ohmmeter indicates continuity in both directions, replace diode assembly.
Connect ohmmeter leads between negative plate and each 3 stator terminals, in turn. Reverse ohmmeter leads. If ohmmeter indicates continuity in only one direction, go to next step. If ohmmeter indicates continuity in both directions, replace diode assembly.
Connect ohmmeter leads between Blue (D+) wire terminal and each 3 stator terminals, in turn. Reverse ohmmeter leads. If ohmmeter indicates continuity in only one direction, diode assembly is okay. If ohmmeter indicates continuity in both directions, replace diode assembly.

Set ohmmeter on lowest scale. Connect ohmmeter leads between stator leads. If resistance is not about .09-.10 ohm, stator windings are open or shorted. Replace stator.
Set ohmmeter on 1000x scale. Connect ohmmeter leads between stator core and stator lead. If continuity exists, stator is grounded. Replace stator.

Set ohmmeter on lowest scale. Connect ohmmeter leads between slip rings. If resistance is less than 2.8 ohms, rotor windings are shorted. Replace rotor. If resistance is greater than 3.1 ohms, high resistance exists in rotor windings. Replace rotor.
Set ohmmeter on 1000x scale. Connect ohmmeter leads between either slip ring and rotor. If continuity exists, rotor is grounded. Replace rotor.
Clean slip rings using sandpaper. If rings are worn or pitted, turn them on lathe. Minimum slip ring diameter is 1 1/16" (27 mm).
If slip rings cannot be repaired, remove rear bearing from slip ring end of rotor. Unsolder wires from slip rings. Bend up ends of rotor winding. Pull off slip rings. Ensure ends of rotor winding are not damaged.
Insert ends of rotor winding into slip ring, and press new slip ring onto rotor until slip ring end is 9/64" (3.57 mm) from end of collar. Solder rotor winding to slip ring terminals. Turn rings on lathe, and retest rotor. Maximum slip ring runout is .0012" (.03 mm).

Ensure new brushes are .47" (12 mm) long. Used brushes must be at least .16" (4 mm) long.