1990 VOLKSWAGEN CORRADO Repair Manual

ANTI-LOCK BRAKE SYSTEM
Article Text (p. 9)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:42PM
Figs. 1, 2, 4-9. There should be continuity at both test points. If
there is no continuity at both test points, repair wiring and retest.
Rear Hydraulic Modulator Inlet Valve Resistance Test
Using an ohmmeter, measure resistance between ECU connector
terminals No. 11 and 17. See Fig. 2. If resistance is 5-7 ohms, go to
next test. If resistance is not 5-7 ohms, measure between hydraulic
modulator block terminals No. 1 (Brown wire) and 5 (Gray wire). See
Fig. 4-9. If resistance is 5-7 ohms, check wiring between hydraulic
modulator and ECU for open circuit. If resistance is not 5-7 ohms,
replace hydraulic modulator.
Right Front Hydraulic Modulator Inlet Valve Resistance Test
Using an ohmmeter, measure resistance between ECU connector
terminals No. 11 and 15. See Fig. 2. If resistance is 5-7 ohms, go to
next test. If resistance is not 5-7 ohms, measure between hydraulic
modulator terminals No. 1 (Brown wire) and 2 (Yellow wire). See
Fig. 4-9. If resistance is 5-7 ohms, check wiring between hydraulic
modulator and ECU for open circuit. If resistance is not 5-7 ohms,
replace hydraulic modulator.
Left Front Hydraulic Modulator Inlet Valve Resistance Test
Using an ohmmeter, measure resistance between ECU connector
terminals No. 11 and 35. See Fig. 2. If resistance is 5-7 ohms, go to
next test. If resistance is not 5-7 ohms, measure between hydraulic
modulator terminals No. 1 (Brown wire) and 7 (Blue or Black/Green
wire). See Figs. 4-9. If resistance is 5-7 ohms, check wiring between
valve block and ECU for open circuit. If resistance is not 5-7 ohms,
replace hydraulic modulator.
Rear Hydraulic Modulator Outlet Valve Resistance Test
Using an ohmmeter, measure resistance between ECU connector
terminals No. 11 and 33. See Fig. 2. If resistance is 3-5 ohms, go to
next test. If resistance is not 3-5 ohms, measure between valve block
terminals No. 1 (Brown wire) and 4 (White wire). See Fig. 4-9. If
resistance is 3-5 ohms, check wiring between hydraulic modulator and
ECU for open circuit. If resistance is not 3-5 ohms, replace hydraulic
modulator.
Right Hydraulic Modulator Block Outlet Valve Resistance Test
Using an ohmmeter, measure resistance between ECU connector
terminals No. 11 and 34. See Fig. 2. If resistance is 3-5 ohms, go to
next test. If resistance is not 3-5 ohms, measure between hydraulic
modulator terminals No. 1 (Brown wire) and 3 (Green wire). See Fig. 4-
9. If resistance is 3-5 ohms, check wiring between hydraulic modulator
and ECU for open circuit. If resistance is not 3-5 ohms, replace
hydraulic modulator.
Left Front Hydraulic Modulator Outlet Valve Resistance Test
Using an ohmmeter, measure resistance between ECU connector
terminals No. 11 and 16. See Fig. 2. If resistance is 3-5 ohms, go to
next test. If resistance is not 3-5 ohms, measure between hydraulic

ANTI-LOCK BRAKE SYSTEM
Article Text (p. 10)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:42PM
modulator terminals No. 1 (Brown wire) and 6 (Black/Blue wire). See
Fig. 4-9. If resistance is 3-5 ohms, check wiring between hydraulic
modulator and ECU for open circuit. If resistance is not 3-5 ohms,
replace hydraulic modulator.
Hydraulic Modulator/Pump Relay Resistance Test
Turn ignition off. Unplug pressure switch connector from
hydraulic modulator. Using an ohmmeter, measure resistance between ECU
connector terminals No. 2 and 14. See Fig. 2. If resistance is 50-100
ohms, go to next test. If resistance is not 50-100 ohms, check wiring.
If wiring is faulty, repair wiring and retest. If wiring is okay,
replace relay and retest.
ABS Main Valve Function Test
Connect a jumper wire between ECU connector terminals No. 2
and 18. See Fig. 2. Depress brake pedal. Turn ignition on. Brake pedal
should rise slightly. If brake pedal did not rise slightly, check
wiring between terminals and hydraulic modulator. If wiring is okay,
replace hydraulic modulator.
Hydraulic Modulator/Pump Test
Turn ignition off. Depress brake pedal 25 times. Turn
ignition on. BRAKE and ANTI-LOCK lights should come on for 2-60
seconds. Pump should operate for 2-60 seconds, then turn off. If
lights do not come on, check wiring and warning light bulbs, and
retest. Also check bulb(s). If lights come on, then turn off, and pump
operates for 60 seconds maximum, then turns off, go to next test. If
pump does not operate and all other preceding tests have been
performed, replace hydraulic modulator/pump.
CAUTION: During VALVE BLOCK FUNCTION TESTS, DO NOT turn ignition on
longer than 60 seconds during any test.
Rear Valve Block Function Test
Connect a jumper wire ECU between ECU connector terminals No.
2, 17 and 33. See Fig. 2. Depress brake pedal. Rear wheels should be
locked up. Turn ignition on. Rear wheels should rotate. If wheels do
not rotate, replace hydraulic modulator. Turn ignition off.
Right Front Valve Block Function Test
Connect a jumper wire ECU between ECU connector terminals No.
2, 15 and 34. See Fig. 2. Depress brake pedal. Right front wheel
should be locked up. Turn ignition on. Right front wheel should
rotate. If wheel do not rotate, replace hydraulic modulator. Turn
ignition off.
Left Front Valve Block Function Test
Connect a jumper wire ECU between ECU connector terminals No.
2, 16 and 35. See Fig. 2. Depress brake pedal. Left front wheel should
be locked up. Turn ignition on. Left front wheel should rotate. If
wheel do not rotate, replace hydraulic modulator. Turn ignition off.

ANTI-LOCK BRAKE SYSTEM
Article Text (p. 11)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:42PM
REMOVAL & INSTALLATION
HYDRAULIC MODULATOR/PUMP
Removal & Installation
1) Depressurize brake system. See DEPRESSURIZING BRAKE
SYSTEM. Disconnect negative battery cable. Unplug all electrical
connectors from hydraulic modulator/pump. Identify and disconnect all
hydraulic lines from hydraulic modulator/pump. Plug all line openings.
2) From inside passenger compartment, remove push rod clevis
pin. Remove hydraulic modulator/pump retaining nuts. Remove hydraulic
modulator/pump. To install, reverse removal procedure. Tighten all
fittings to specification. See TORQUE SPECIFICATIONS TABLE at end of
article. Bleed brake system. See BLEEDING BRAKE SYSTEM.
WHEEL SPEED SENSORS
NOTE: To protect magnetic part of sensor, always leave new wheel
speed sensor in special packaging until ready for
installation.
Removal & Installation
Remove bolt retaining wheel speed sensor. Unplug connector.
Remove wheel speed sensor. To install, apply Lubricant (G-000-650) to
sensor. Install sensor, and tighten retaining bolt to 84 INCH lbs. (10
N.m).
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLEÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄApplications Ft. Lbs. (N.m)
Brake Lines-To-Hydraulic Modulator/Pump ............... 11 (15)
Hydraulic Modulator/Pump Retaining Nuts ............... 18 (25)
INCH Lbs. (N.m)
Wheel Sensor Retaining Bolt .......................... 84 (9.5)
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ WIRING DIAGRAMS

ANTI-LOCK BRAKE SYSTEM
Article Text (p. 12)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:42PMFig. 4: Corrado ABS Wiring Diagram (1991)

ANTI-LOCK BRAKE SYSTEM
Article Text (p. 13)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:42PMFig. 5: Corrado ABS Wiring Diagram (1990)

ANTI-LOCK BRAKE SYSTEM
Article Text (p. 14)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:42PMFig. 6: Jetta ABS Wiring Diagram (1990-91)

ANTI-LOCK BRAKE SYSTEM
Article Text (p. 15)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:42PMFig. 7: Passat ABS Wiring Diagram (1990-91)

ANTI-LOCK BRAKE SYSTEM
Article Text (p. 16)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:43PMFig. 8: Corrado ABS Wiring Diagram (1992)