check engine VOLKSWAGEN CORRADO 1993 Repair Manual

F - BASIC TESTING
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 09:10PM
to specification. If necessary, see the appropriate D - ADJUSTMENTS
article in this section. Refer to the following menu:
NOTE: For the appropriate D - ADJUSTMENTS article, go to:
* For Cabriolet, see: D - ADJUSTMENTS
* For Corrado SLC, see: D - ADJUSTMENTS
* For EuroVan, see: D - ADJUSTMENTS
* For Fox, see: D - ADJUSTMENTS
* For Golf, GTI, Jetta, see: D - ADJUSTMENTS
* For Passat GL 2.0L 4-Cylinder, see: D - ADJUSTMENTS - 4-CYL
* For Passat GLX 2.8L VR6, see: D - ADJUSTMENTS - VR6
IDLE SPEED & CO LEVELÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄApplication Idle RPM CO Level %
Cabriolet (1)
Digifant I ............. 750-850 ......... 0.3-1.2
Digifant II ............ 750-850 ......... 0.3-1.1
Corrado SLC (2) ......... 650-750 ......... 0.3-1.5
Fox ................... (3) 875-925 ....... 0.3-1.2
Golf, Jetta & GTI (2)
800-880
0.3-1.2
Passat GL ............ (4) 800-1000 ....... 0.2-1.2
Passat GLX (2) .......... 650-750 ......... 0.3-1.5
(1) - With engine running, after reconnecting Blue coolant
temperature sensor. See the D - ADJUSTMENTS article
in this section for more information. See menu above.
(2) - Idle speed and fuel mixture (CO level) are not
adjustable.
(3) - If A/C equipped, disconnect idle speed boost valve
harness connector when checking idle speed. Clamp
crankcase breather hose near emission control valve
when checking CO level.
(4) - Idle speed is not adjustable.
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄIGNITION TIMING (Degrees BTDC @ RPM)
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄApplication Checking Adjusting
Cabriolet (1) ....... 4-8 @ 2000-2500 .. 5-7 @ 2000-2500
Corrado SLC ............... (2) .................... (2)
Fox (1) ............. 4-8 @ 2000-2500 .. 5-7 @ 2000-2500
Golf, GTI & Jetta ... (3) 12 @ 800-880 ............ .....
Passat GL ........... 4-8 @ 800-1000 .... 5-7 @ 800-1000
Passat GLX ................ (2) .................... (2)
(1) - On Digifant I systems, ensure engine oil temperature

G - TESTS W/CODES
Article Text
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:11PM
ARTICLE BEGINNING
1993 ENGINE PERFORMANCE
Volkswagen Self-Diagnostics
Corrado SLC
INTRODUCTION
If no faults were found while performing preliminary
inspection procedures, proceed with self-diagnostics. If no fault
codes or only pass codes are present after entering self-diagnostics,
proceed to H - TESTS W/O CODES article for diagnosis by symptom (i.e.,
ROUGH IDLE, NO START, etc.).
NOTE: Scan Tester (VAG 1551) must be used to make full use of the
self-diagnostic system capabilities.
SELF-DIAGNOSTIC SYSTEM DESCRIPTION
Hard Failures
Hard failures of monitored sensors and/or components, cause
Malfunction Indicator Light (MIL) to come on and remain on until
problem is repaired. If malfunction indicator CHECK ENGINE light comes
on and remains on during vehicle operation, cause of malfunction must
be determined.
If malfunctions are present for more than 5 seconds, they are
stored as Diagnostic Trouble Codes (DTCs) and will be displayed as a
permanent malfunction even though the malfunction is not occurring at
the time DTCs are displayed. Malfunctions that affect oxygen sensor
control can only be read accurately after a test drive of at least 5
minutes.
Intermittent Failures
If a malfunction occurs for a maximum of 5 seconds, they are
stored and considered to be "sporadic" (intermittent failures). When
displayed on scan tester, malfunctions will have "SP" (sporadic) code.
RETRIEVING CODES
NOTE: See ENTERING SELF-DIAGNOSTICS for additional scan tester
operating instructions.
Corrado SLC
1) Turn ignition on. Connect Jumper Cable (357 971 514E) to
Data Link Connectors (DLC) located in center console. See Fig. 1.
Black end of jumper cable attaches to Black data link connector; White
end of cable attaches to White connector.
2) Leave jumper cable attached for 5 seconds, until on-board
diagnostic CHECK ENGINE light begins to blink. Remove jumper cable.
Allow on-board diagnostic code retrieval procedure to run until Code

G - TESTS W/CODES
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 09:11PM
4444 (no faults indicated) or Code 0000 (end of output) appears. To
end code retrieval procedure, reconnect jumper cable to data link
connectors or turn ignition off.
3) To erase fault codes, turn ignition off. Connect jumper
cable and turn ignition on. Leave jumper cable attached for 5 seconds,
until CHECK ENGINE light begins to blink.
4) When light displays code 4444 (no faults indicated),
reconnect jumper cable to data link connectors or turn ignition off to
end code clearing procedure. Fault memory is now erased.Fig. 1: Retrieving Fault Codes (Typical)
Courtesy of Volkswagen United States, Inc.
ECM LOCATION
ECU/ECM LOCATIONÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄApplication Location
Corrado .......... Below fresh air intake on firewall

G - TESTS W/CODES
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 09:11PM
Exceeded
00585 (2411) ... EGR Temperature Sensor ...... Short Ckt To Ground
Or Faulty Sensor
00586 (----) ........ EGR Control ........ EGR Valve Sticking Open
01025 (----) .. Malfunction Indicator Light .... Open/Short Ckt To
Ground Or Battery
Voltage
01242 (4332) ...... ECM Output Stage ........ Faulty Ckt To Output
Check Controlled
Components
01247 (4343) ... EVAP Frequency Solenoid ...... Open/Short Ckt To
Ground Or Battery
Voltage
01249 (4411) ....... Injector No. 1 ............ Open/Short Ckt To
Ground Or Battery
Voltage
01250 (4412) ....... Injector No. 2 ............ Open/Short Ckt To
Ground Or Battery
Voltage
01251 (4413) ....... Injector No. 3 ............ Open/Short Ckt To
Ground Or Battery
Voltage
01252 (4414) ....... Injector No. 4 ............ Open/Short Ckt To
Ground Or Battery
Voltage
01253 (4415) ....... Injector No. 5 ............ Open/Short Ckt To
Ground Or Battery
Voltage
01254 (4422) ....... Injector No. 6 ............ Open/Short Ckt To
Ground Or Battery
Voltage
01257 (4431) .. Idle Air Control (IAC) Valve ... Open/Short Ckt To
Ground Or Battery
Voltage
01259 (4433) ....... Fuel Pump Relay ....... Open Ckt Or Short Ckt
To Battery Voltage
01265 (4312) .. EGR Frequency (2-Way) Valve .... Open/Short Ckt To
Ground Or Battery
Voltage
65535 (1111) ... Electronic Control Module .... Replace Faulty ECM
(1) - For testing information, see J - PIN VOLTAGE CHARTS article.
(2) - Blink code is 4-digit malfunction indicator CHECK ENGINE
light code.
(3) - Check intake and exhaust systems for leaks. Check for too low
or too high a fuel pressure. Also check for malfunctioning
fuel injectors or engine misfire.
(4) - Check intake and exhaust systems for leaks. Check for mass
airflow sensor hot wire not burning off cleanly. Check for
faulty oxygen sensor control and for EVAP frequency solenoid
sticking open. Also check for malfunctioning fuel injectors or
engine misfire.

G - TESTS W/CODES
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 09:11PMÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ ENTERING SELF-DIAGNOSTICS
VAG ON-BOARD DIAGNOSTICS
NOTE: If VAG SELF-DIAGNOSIS (VAG ON-BOARD DIAGNOSTIC) display
does not appear on scan tester, check DLC terminals for
battery voltage and ground. Upper terminal should have
battery voltage, bottom terminals serve as ground.
Corrado SLC
1) Ensure battery voltage and fuses No. 18 and 22 are okay.
Ensure engine ground connections at cylinder head cover and at
manifold are okay.
2) Connect Scan Tester (VAG 1551) to Data Link Connectors
(DLC) located in center console, in front of shift lever. Attach Black
connector first, wait for VAG ON-BOARD DIAGNOSTIC display, then
connect White connector. DO NOT connect scan tester Blue connector.
3) Turn ignition on or start engine depending on function
being selected. See appropriate SELECTABLE FUNCTIONS table. Press "1"
button to select RAPID DATA TRANSFER function.
4) Press "0" and "1" buttons to select ENGINE ELECTRONICS
function. Press "Q" button to enter input. Electronic Control Module
(ECM) identification will be displayed on scan tester.
5) If CONTROL MODULE DOES NOT ANSWER message is displayed,
press HELP button to print a list of possible causes. With scan tester
in RAPID DATA TRANSFER function, press right arrow button. Press "02"
to "08" buttons to select desired function. Press "Q" button to enter
input.
SELECTABLE FUNCTIONS (CORRADO SLC) (1)
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄFunction Ignition On Engine On
02 (Read DTC/Fault Memory) .. ..... ............. X
03 (Output Check/
03 Diagnostic Test Mode) ...... X .......... .....
04 (Start Basic Setting) ..... ..... ............. X
05 (Erase DTC/Fault Memory) .. ..... ............. X
06 (End Output) ............... X ............... X
08 (Read Measuring Value Block) X ............... X
(1) - Press HELP button at any time to obtain additional
scan tester operating instructions.
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ OUTPUT CHECK DIAGNOSIS (OUTPUT DIAGNOSTIC TEST MODE)
NOTE: See ENTERING SELF-DIAGNOSTICS for additional scan tester
operating instructions.

GENERAL COOLING SYSTEM SERVICING
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 09:11PM
To flush engine, remove thermostat and replace housing.
Connect flushing gun to water outlet of engine. Flush using short air
bursts until water runs clean.
Heater Core
Flush heater core as described for radiator. Ensure heater
control valve is set to maximum heat position before flushing heater.
REFILLING
To prevent air from being trapped in engine block, engine
should be running when refilling cooling system. After system is full,
continue running engine until thermostat is open, then recheck fill
level. Do not overfill system.
TESTING
THERMOSTAT
1) Visually inspect thermostat for corrosion and proper
sealing of valve and seat. If okay, suspend thermostat and thermometer
in a 50/50 mixture of coolant and water. See Fig. 1. Do not allow
thermostat or thermometer to touch bottom of container. Heat water
until thermostat just begins to open.
2) Read temperature on thermometer. This is the initial
opening temperature and should be within specification. Continue
heating water until thermostat is fully open and note temperature.
This is the fully opened temperature. If either reading is not to
specification, replace thermostat.Fig. 1: Testing Thermostat in Anti-Freeze/Water Solution
PRESSURE TESTING
A pressure tester is used to check both radiator cap and
complete cooling system. Test components as follows, following tool

H - TESTS W/O CODES
Article Text
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:11PM
ARTICLE BEGINNING
1993 ENGINE PERFORMANCE
Volkswagen Trouble Shooting - No Codes
Cabriolet, Corrado SLC, EuroVan, Fox
Golf, GTI, Jetta, Passat GL, Passat GLX
INTRODUCTION
PRELIMINARY INFORMATION
Before diagnosing symptoms or intermittent faults, perform
steps in the F - BASIC TESTING article in this section. Use this
article to diagnose driveability problems existing when a hard fault
code is not present or vehicle is not equipped with a self-diagnostic
system.
NOTE: Some driveability problems may have been corrected by
manufacturer with a revised computer calibration chip or
computer control unit. Check with manufacturer for latest
chip or computer application.
Symptom checks can direct the technician to malfunctioning
component(s) for further diagnosis. A symptom should lead to a
specific component, system test or an adjustment.
Use intermittent test procedures to locate driveability
problems that DO NOT occur when the vehicle is being tested. These
test procedures should also be used if a soft (intermittent) trouble
code was present, but no problem was found during self-diagnostic
testing.
NOTE: For specific test procedures, see the I - SYS/COMP TESTS
article in this section. For adjustment procedures, see the
appropriate D - ADJUSTMENTS article. For Engine Performance
related specifications, see appropriate C - SPECIFICATIONS
article in this section. See the following menus:
C - SPECIFICATIONS ARTICLES MENU
NOTE: For the appropriate C - SPECIFICATIONS article, go to:
* For Cabriolet, see: C - SPECIFICATIONS
* For Corrado SLC, see: C - SPECIFICATIONS
* For EuroVan, see: C - SPECIFICATIONS
* For Fox, see: C - SPECIFICATIONS
* For Golf, GTI, Jetta, see: C - SPECIFICATIONS
* For Passat, see: C - SPECIFICATIONS
D - ADJUSTMENTS ARTICLES MENU
NOTE: For the appropriate D - ADJUSTMENTS article, go to:

H - TESTS W/O CODES
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 09:11PM
* For Cabriolet, see: D - ADJUSTMENTS
* For Corrado SLC, see: D - ADJUSTMENTS
* For EuroVan, see: D - ADJUSTMENTS
* For Fox, see: D - ADJUSTMENTS
* For Golf, GTI, Jetta, see: D - ADJUSTMENTS
* For Passat GL 2.0L 4-Cylinder, see: D - ADJUSTMENTS - 4-CYL
* For Passat GLX 2.8L VR6, see: D - ADJUSTMENTS - VR6
I - SYS/COMP TESTS ARTICLES MENU
NOTE: For the appropriate I - SYS/COMP TESTS article, go to:
* For Cabriolet, see: I - SYSTEM/COMPONENT TESTS
* For Corrado SLC, see: I - SYSTEM/COMPONENT TESTS
* For EuroVan, see: I - SYSTEM/COMPONENT TESTS
* For Fox, see: I - SYSTEM/COMPONENT TESTS
* For Golf, GTI, Jetta, see: I - SYSTEM/COMPONENT TESTS
* For Passat GL 2.0L 4-Cylinder, see:
I - SYSTEM/COMPONENT TESTS - 4-CYL
* For Passat GLX 2.8L VR6, see:
I - SYSTEM/COMPONENT TESTS - VR6
SYMPTOMS
SYMPTOM DIAGNOSIS
Symptom checks cannot be used properly unless the problem is
actually happening while the vehicle is being tested. To reduce
diagnostic time, ensure battery voltage is okay and starter motor
turns engine over before attempting to diagnose a symptom.
Check engine mechanical condition (compression pressure,
valve timing, etc.), wiring harness and connections (terminals not
corroded or pushed back), and vacuum hose (not disconnected or
leaking).
Also check for correct tire sizes, as recommended by
manufacturer. Ensure wheels rotate freely (brake drag or bad wheel
bearings). Ensure no speed reducing accessories are installed.
Symptoms available for diagnosis include the following.
* Engine Does Not Start Or Is Difficult To Start When Cold
* Engine Does Not Start Or Is Difficult To Start When Warm
* Uneven Idle Or No Idle With Cold Engine Or During Warm-Up
* Engine Starts But Stalls
* Idle Speed Exceeds Specification
* Poor Acceleration With Cold Engine Or During Warm-Up
* Engine Stalls While Driving
* Poor Performance
* Engine Run-On (Dieseling)
* High Fuel Consumption
* Engine Knock
* Engine Runs Unevenly Over Entire Speed Range

H - TESTS W/O CODES
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 09:11PM
NOTE: Symptoms listed are for CIS-E Motronic system. When working
on Digifant and Motronic systems, use symptoms listed only
as a diagnostic guide. A list of specific symptoms for
Digifant and Motronic systems is not available from
manufacturer.
ENGINE DOES NOT START OR IS DIFFICULT TO START WHEN COLD
* Check for insufficient fuel in tank.
* Check fuel pump relay and fuel pump.
* Check fuel system for leaks.
* Check auxiliary air intake system.
* Check fuel system after-start, acceleration enrichment and
warm-up circuits.
* Check cold-start valve.
* Check airflow sensor lever adjustment and control plunger.
* Check sensor plate rest position and idle circuit.
* Check fuel system differential and residual pressures.
* Check fuel injection volume.
* Check engine coolant temperature sensor.
* Check ignition timing, spark plugs, distributor, secondary
ignition wiring and coil.
* Check Hall Effect sensor.
* Check ignition coil power output stage.
ENGINE DOES NOT START OR IS DIFFICULT TO START WHEN WARM
* Check radiator cooling fan after-run circuit.
* Check fuel pump check valve.
* Check fuel evaporative frequency solenoid(s).
* Check fuel system for leaks.
* Check auxiliary air intake system.
* Check idle speed.
* Check fuel system after-start, acceleration enrichment and
warm-up circuits.
* Check cold-start valve.
* Check injector fuel pressure and volume.
* Check sensor plate rest position and idle circuit.
* Check sealing ring under control plunger.
* Check fuel system differential and residual pressures.
* Check engine coolant temperature sensor.
* Check ignition timing, spark plugs, distributor, secondary
ignition wiring and coil.
UNEVEN IDLE OR NO IDLE WITH COLD ENGINE OR DURING WARM-UP
* Check fuel evaporative frequency solenoid(s).
* Check fuel system for leaks.
* Check auxiliary air intake system.
* Check idle speed.
* Check oxygen sensor control circuit.

H - TESTS W/O CODES
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 09:11PM
* Check cold-start valve.
* Check injector fuel pressure and volume.
* Check throttle potentiometer.
* Check fuel system differential and residual pressures.
* Check idle switch.
* Check engine coolant temperature sensor.
* Check exhaust system.
* Check ignition timing and spark plugs.
ENGINE STARTS BUT STALLS
* Check fuel pump relay and fuel pump.
* Check auxiliary air intake system.
* Check idle speed.
* Check fuel system after-start, acceleration enrichment and
warm-up circuits.
* Check airflow sensor lever adjustment and control plunger.
* Check sensor plate rest position and idle circuit.
* Check fuel system differential and residual pressures.
* Check idle switch.
* Check engine coolant temperature sensor.
IDLE SPEED EXCEEDS SPECIFICATION
* Check throttle cable adjustment.
* Check fuel evaporative frequency solenoid(s).
* Check auxiliary air intake system.
* Check idle speed.
* Check throttle potentiometer.
* Check idle switch.
* Check engine coolant temperature sensor.
* Check throttle body basic adjustment.
* Check ignition timing.
POOR ACCELERATION WITH COLD ENGINE OR DURING WARM-UP
* Check fuel pump.
* Check auxiliary air intake system.
* Check oxygen sensor control circuit.
* Check fuel system after-start, acceleration enrichment and
warm-up circuits.
* Check airflow sensor lever adjustment and control plunger.
* Check throttle potentiometer.
* Check fuel system differential and residual pressures.
* Check injector fuel pressure and volume.
* Check idle switch.
* Check engine coolant temperature sensor.
* Check throttle body basic adjustment.
* Check exhaust system.
* Check ignition timing, spark plugs, distributor, secondary
ignition wiring and coil.