1993 VOLKSWAGEN CORRADO light

ANTI-LOCK BRAKE SYSTEM
Article Text (p. 2)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:57PM
to protect the hydraulic modulator and ECU.
NOTE: For more brake system information, see BRAKE SYSTEM
article in the BRAKES section.
OPERATION
When pressure is applied to brake pedal, ECU monitors input
signals from each wheel speed sensor. If ECU measures a rate of
reduction greater than what is programmed in ECU, the ECU will output
a signal to appropriate solenoid valve. Each solenoid valve allows
hydraulic pressure to increase or decrease to the appropriate wheel
cylinder.
If a system failure occurs, ANTILOCK warning light, located
on instrument panel, will come on. System will be deactivated, but
conventional brake system will still operate. If brake fluid level
drops too low, BRAKE warning light, located on instrument panel, will
come on.
CAUTION: See ANTI-LOCK BRAKE SAFETY PRECAUTIONS in this article.
CAUTION: The ABS system is under extremely high pressure. Depressurize
the brake system before loosening or removing any hydraulic
component.
DEPRESSURIZING BRAKE SYSTEM
Turn ignition off. Depress and release brake pedal 25-35
times, or until there is a noticeable increase in the effort to
depress the brake pedal. DO NOT turn ignition on until all hydraulic
lines and components are fully tighten.
BLEEDING BRAKE SYSTEM
FRONT BRAKES
Depressurize brake system. See DEPRESSURIZING BRAKE SYSTEM.
Connect a container with hose to left front bleeder screw. Have
assistant depress and release brake pedal a few times. Holding brake
pedal down, open bleeder screw and allow fluid to enter container.
Close bleeder screw and then release brake pedal. Continue this method
until no air is present in fluid. Check master cylinder fluid level to
make sure it does not go below minimum level mark. Use same procedure
for right front brake.
REAR BRAKES
CAUTION: When bleeding rear brakes, accumulator pressure (about 3100
psi) is used to assist in procedure. Use eye protection when
performing this procedure. DO NOT allow pump to run longer
than 2 minutes. See ANTI-LOCK BRAKE SAFETY PRECAUTIONS in

ANTI-LOCK BRAKE SYSTEM
Article Text (p. 4)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:57PM
HYDRAULIC MODULATOR/PUMP
Depressurize brake system. See DEPRESSURIZING BRAKE SYSTEM.
Turn ignition on. Hydraulic modulator/pump should operate for 60
seconds maximum and then stop. Depress brake pedal a few times; pump
should operate again for a few seconds. If pump motor does not
operate, check electrical system. If pump motor operates for more than
60 seconds, internal or external hydraulic leak may be indicated.
Check for external leaks. If external leak is not found, further
testing may be needed to check for internal leaks.
ANTILOCK WARNING LIGHT
Start engine. ANTILOCK warning light should come on, then
turn off after a few seconds. If light does not come on when engine is
started, check electrical system. If light comes on and stays on,
fault has been detected by the ECU and testing will be needed. See
SYSTEM TESTING under DIAGNOSIS & TESTING.
DIAGNOSIS & TESTING
SYSTEM TESTING
NOTE: Check battery condition, brake fluid level, electrical
connections and wiring for damage. If fluid level is
incorrect or battery and/or electrical connections are
faulty, correct problem before preceding. Perform each step,
in sequence, to test entire system, except for ECU. If
faulty ECU is suspected, replace with a known good one, and
retest system. Unplug ECU connector for all test steps.
Power-To-ECU Test
Turn ignition off. Unplug ECU connector. Turn ignition on.
Using a voltmeter, check voltage between ECU connector terminals No. 1
and 2. See Fig. 2. If voltage is 10 volts or more, go to next test. If
voltage is less than 10 volts, check battery, ground, ABS fuse, relay
and wiring. Repair as necessary.Fig. 2: Identifying ECU Connector Terminals
Courtesy of Volkswagen United States, Inc.
ECU Relay Voltage Test
Connect a jumper wire between ECU connector terminals No. 2
and 8. See Fig. 2. Turn ignition on. Using a voltmeter, check voltage
between ECU connector terminals No. 1 and 3. If voltage is 10 volts or
more, go to next test. If voltage is less than 10 volts, check ABS

ANTI-LOCK BRAKE SYSTEM
Article Text (p. 5)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:57PM
fuse. If fuse is faulty, replace and retest. If fuse is okay, check
wiring. If wiring is faulty, repair and retest. If wiring is okay,
replace relay and retest.
Brakelight Switch
Turn ignition on. Apply brakes. Check for 12 volts between
terminals No. 12 and 1. If 12 volts are present, brakelight switch is
okay. If 12 volts are not present, check fuse, brakelight switch and
Black/Red wire from brakelight switch to ECU.
Hydraulic Modulator/Pump Relay Voltage Test
1) Turn ignition off. Unplug hydraulic modulator/pump
connector. Depress brake pedal 25 times. Turn ignition on. Using a
voltmeter, measure voltage between ECU connector terminals No. 1 and
32. See Fig. 2. If voltage is 10 volts or more, go to RIGHT REAR WHEEL
SPEED SENSOR VOLTAGE TEST under SYSTEM TESTING.
2) If voltage is less than 10 volts, check hydraulic
modulator/pump fuse. If fuse is okay, check wiring between ECU
connector terminal No. 32 and hydraulic modulator/pump connector
terminal No. 1 (large gauge Red/Black wire). See Figs. 2 and 4. If
wiring is not okay, repair wiring, and retest. If wiring is okay,
replace relay, and retest.
Right Rear Wheel Speed Sensor Voltage Test
Connect an AC voltmeter between ECU connector terminals No. 4
and 22. See Fig. 2. Rotate right rear wheel at one revolution per
second. Measure voltage with wheel rotating. If voltage is 0.075 volt
or more, go to next test. If voltage is less than 0.075 volt, check
wheel speed sensor and/or toothed ring for damage, wear and proper
installation. If damage or wear is found, replace faulty component and
retest. If components are not properly installed, reposition and
retest. If components are okay, replace wheel speed sensor and retest.
Left Rear Wheel Speed Sensor Voltage Test
Connect an AC voltmeter between ECU connector terminals No. 6
and 24. See Fig. 2. Rotate left rear wheel at one revolution per
second. Measure voltage with wheel rotating. If voltage is 0.075 volt
or more, go to next test. If voltage is less than 0.075 volt, check
wheel speed sensor and/or toothed ring for damage, wear and proper
installation. If damage or wear is found, replace faulty component and
retest. If components are not properly installed, reposition and
retest. If components are okay, replace wheel speed sensor and retest.
Right Front Wheel Speed Sensor Voltage Test
Connect an AC voltmeter between ECU connector terminals No. 7
and 25. See Fig. 2. Rotate right front wheel at one revolution per
second. Measure voltage with wheel rotating. If voltage is 0.075 volt
or more, go to next test. If voltage is less than 0.075 volt, check
wheel speed sensor and/or toothed ring for damage, wear and improper
installation. If damage or wear is found, replace faulty component,
and retest. If components are improperly installed, reposition
component, and retest. If components are okay, replace wheel speed

ANTI-LOCK BRAKE SYSTEM
Article Text (p. 10)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:57PM
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
modulator terminals No. 1 (Brown wire) and No. 6 (Black/Blue wire).
See Fig. 4. 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 ANTILOCK 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 does not rotate, replace hydraulic modulator. Turn
ignition off.
Left Front Valve Block Function Test

ANTI-THEFT SYSTEM
Article Text (p. 2)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:57PM
Black/Yellow wire for Passat). If 12 volts are present, go to next
step. If 12 volts are not present, repair open circuit.
4) Alarm Horn Check
Turn ignition off. Connect ohmmeter negative lead to ground.
Connect positive lead to anti-theft control module 6-pin wiring
harness connector terminal No. "4" (Black/Yellow wire). If continuity
is present, go to next step. If continuity is not present, repair open
circuit. If circuit is okay, replace alarm horn.
5) Door Lock Switch Check
Connect voltmeter negative lead to ground. Connect positive
lead to anti-theft control module 10-pin wiring harness connector
terminal No. "7" (Red/Yellow wire for Corrado; Yellow/Red for Passat).
Insert key in driver's door lock. Turn key to lock position and hold
momentarily. Voltmeter should register 12 volts. Repeat procedure for
passengers door. If voltage is correct for each door, go to next step.
If voltage is not correct, repair open circuit or replace switch.
6) Door Lock Switch Check
Connect voltmeter negative lead to ground. Connect positive
lead to anti-theft control module 10-pin wiring harness connector
terminal No. "6" (Red/Black wire). Insert key in driver's door lock.
Turn key to unlocked position and hold momentarily. Voltmeter should
register 12 volts. Repeat procedure for passengers door. If voltage is
correct for each door, go to next step. If voltage is not correct,
repair open circuit or replace switch.
7) Alarm Switch & Hood Check
Connect ohmmeter negative lead to ground. Disconnect negative
battery cable. Connect positive lead to the following anti-theft
control module connector terminals:
* 10-pin harness connector terminal No. "5" (Gray wire).
* 10-pin harness connector terminal No. "8" (Brown/Red wire).
* 10-pin harness connector terminal No. "9" (Brown/Green wire).
* 10-pin harness connector terminal No. 10 (Brown/White wire for
Corrado SLC; Brown/Green wire for Passat).
If continuity is present, check for circuit short to ground. If
circuit is okay, replace switch. If continuity is not present, go to
next step.
8) Indicator Light Check
Leave ohmmeter negative lead connected to ground. Connect
negative battery cable. Using multimeter set on 10 A DC scale, connect
positive lead to anti-theft control module 10-pin wiring harness
connector terminal No. "2". If indicator light comes on, replace anti-
theft control module. If indicator light does not come on, repair open
circuit in wiring harness.
ALARM SYSTEM WILL NOT SWITCH OFF
1) Ground Circuit Check
Ensure battery is fully charged. Obtain radio security code.
Disconnect battery cable terminals. Disconnect anti-theft control
module 6-pin and 10-pin wiring harness connector. See ANTI-THEFT
CONTROL MODULE LOCATION table. Reconnect battery cable terminals.
2) Connect voltmeter negative lead to ground. Connect

ANTI-THEFT SYSTEM
Article Text (p. 3)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:57PM
positive lead to anti-theft control module 10-pin wiring harness
connector terminal No. "7" (Red/Yellow wire for Corrado SLC;
Yellow/Red wire for Passat). Insert key in driver's door lock. Turn
key against stop and hold momentarily. Voltmeter should register 12
volts. Repeat procedure for passengers door. If voltage is correct for
each door, go to next step. If voltage is correct, repair door switch
or open circuit.
3) Door Lock Switch Check
Connect voltmeter negative lead to ground. Connect positive
lead to anti-theft control module 10-pin wiring harness connector
terminal No. "6" (Red/Black wire). Insert key in driver's door lock.
Turn key against stop and hold momentarily. Voltmeter should register
12 volts. Repeat procedure for passengers door. If voltage is correct
for each door, replace control module. If voltage is not correct,
repair door switch or open circuit.
ALARM HORN INOPERATIVE
1) Alarm Horn Check
Ensure battery is fully charged. Obtain radio security code.
Disconnect battery cable terminals. Disconnect anti-theft control
module 6-pin and 10-pin wiring harness connector. See ANTI-THEFT
CONTROL MODULE LOCATION table.
2) Connect ohmmeter negative lead to ground. Connect positive
lead to anti-theft control module 6-pin wiring harness connector
terminal No. "4" (Black/Yellow wire). If continuity is present,
replace anti-theft control module. If continuity is not present, check
for open circuit and repair as necessary. If circuit is okay, replace
alarm horn.
LIGHTS DO NOT FLASH
1) Alarm Horn Check
Ensure battery is fully charged and emergency flasher system
is functional. Obtain radio security code. Disconnect battery cable
terminals. Disconnect anti-theft control module 6-pin and 10-pin
wiring harness connector. See ANTI-THEFT CONTROL MODULE LOCATION
table.
2) Connect voltmeter negative lead to ground. Connect
positive lead to anti-theft control module 6-pin wiring harness
connector terminal No. "1" (Black/White wire for Corrado SLC; Black
Yellow wire for Passat). Turn emergency flashers on. When lights flash
on, battery voltage should be present.
3) Remove voltmeter positive from terminal No. "1" and
connect to terminal No. "2" (Black/Green wire for Corrado SLC;
Green/Black wire for Passat). Turn emergency flashers on. When lights
flash on, battery voltage should be present. If voltage is correct,
replace anti-theft control module. If voltage is not correct, repair
open circuit in wiring harness between anti-theft control module and
lights.
ENGINE DOES NOT CRANK WITH ALARM SYSTEM OFF

B - EMISSION APPLICATION
Article Text (p. 2)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:57PM
2.0L 4-Cyl. CIS-E Motronic
Major Control Systems & Devices ............. PCV, EVAP, TWC, FR,
(2) EGR, SPK, AP,
(1) O2, CEC, (2) MIL
Components & Other Related Devices ........ (4) EVAP-PV, EVAP-CV,
EGR-VA, EGR-TVV, SPK-CC
2.8L VR6 Motronic MFI
Major Control Systems & Devices ........ PCV, EVAP, TWC, FR, EGR,
SPK, AP, (1) O2, CEC, (2) MIL
Components & Other Related Devices ...... AP-EAP, AP-ERLY, AP-SV,
AP-SOV, EVAP-PV, EVAP-VC,
EGR-CV, EGR-TS, SPK-CC
(1) - Heated O2 sensor.
(2) - California only.
(3) - Digifant II only.
(4) - Two required.ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ ABBREVIATION DEFINITIONS
ABBREVIATION DEFINITION TABLE
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄAbbreviation Definition
AP ............................. Air Pump Injection System
AP-EAP .............................. AP Electric Air Pump
AP-ERLY ....................... AP Electric Air Pump Relay
AP-SV .......................... AP Solenoid (Inlet) Valve
AP-SOV ................................. AP Shut Off Valve
CEC ......................... Computerized Engine Controls
EGR ............................ Exhaust Gas Recirculation
EGR-CV ..................... EGR Control (Frequency) Valve
EGR-TS ............................ EGR Temperature Sensor
EGR-TVV ......................... EGR Thermal Vacuum Valve
EGR-VA .............................. EGR Vacuum Amplifier
EVAP ............................. Fuel Evaporative System
EVAP-CS ............................ EVAP Control Solenoid
EVAP-PV ................................. EVAP Purge Valve
EVAP-VC .............................. EVAP Vapor Canister
FR .................................. Fill Pipe Restrictor
HAI ....................................... Hot Air Intake
MIL ........... Malfunction Indicator (CHECK ENGINE) Light
MFI ............................. Multiport Fuel Injection
O2 ......................................... Oxygen Sensor
PCV ....................... Positive Crankcase Ventilation
SPK ................................. Spark Control System
SPK-CC ........................... SPK Computer Controlled
TWC ................................... Three-Way Catalyst
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄEND OF ARTICLE

BRAKE SYSTEM
Article Text (p. 3)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:57PMFig. 1: Identifying Brake Pressure Regulator Components (Typical)
Courtesy of Volkswagen United States, Inc.
BRAKE PRESSURES TABLEÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Front Gauge Rear Gauge
Application psi (kg/cm
ý) psi (kg/cmý)
1st Reading ......... 725 (51) ......... 391-478 (28-34)
2nd Reading ........ 1450 (102) ........ 696-783 (49-55)
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ STOPLIGHT SWITCH
NOTE: Stoplight switches mounted on master cylinder are
non-adjustable.
Adjustable stoplight switch is located above brake pedal. See
Fig. 2. To adjust, loosen lock nut. Turn switch until distance between
brake pedal arm and first thread on switch body is .20-.24" (5-6 mm).
Tighten lock nut.Fig. 2: Adjusting Stoplight Switch
Courtesy of Volkswagen United States, Inc.