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System Testing

Following VOLTAGE CHECKS and RESISTANCE CHECKS charts show procedure for checking CIS-E system components from ECU connector. ECU connector terminal numbers are called out in testing procedures. Ignition MUST be off whenever ECU connector is disconnected or reconnected. Use care to avoid any terminal damage when testing, removing or attaching connectors.

Always check all connections used in test procedure. If readings are incorrect, disconnect terminals and determine if wiring or components are at fault. High tension lead (from coil) at distributor cap should be removed and grounded. Use Digital Multimeter (US 1119).

Fig 1: Fox ECU Connector
G93406Courtesy of VOLKSWAGEN UNITED STATES, INC.
16 VALVE CIS-E INJECTION - VOLTAGE CHECKS

Voltmeter Between Terminals Test Conditions (1) Specifications
No. 1 & 2 Ignition on Battery voltage
No. 2 & 3 Ignition on Battery voltage
No. 2 & 4 Ignition on Battery voltage
No. 2 & 5 Ignition on, operate throttle switch to full on position. Battery voltage
No. 2 & 13 Ignition on. Throttle at idle position, ensure idle switch is on. Battery Voltage
No. 2 & 24 Operate Starter Minimum 8 Volts
No. 2 & 25 Use LED Tester (US 1115), operate starter. LED must flicker. If not, check for open wire 25 to ignition ECU. If wire is okay, check wiring between ignition distributor and ignition ECU. If wiring is good, replace Hall sensor. If wiring and Hall sensor are good, replace ignition ECU.
No. 2 & 6 (2) Ignition On, Switch On A/C. Battery voltage
No. 2 & 16 (2) Ignition On, Switch On A/C. Battery voltage
No. 2 & 19 (2) Ignition On, Switch On A/C. Battery voltage
(1) TESTING CONDITIONS: Disconnect and ground high tension lead (from coil) at distributor cap. Unplug ECU connector with ignition off. Set multimeter to 20-volt DC scale.
(2) Vehicles with A/C.
Fig 2: All Except Fox ECU Connector
G93407Courtesy of VOLKSWAGEN UNITED STATES, INC.
16 VALVE CIS-E INJECTION - RESISTANCE CHECKS

Ohmmeter Between Terminals Test Conditions (1) Specifications
No. 2 & 7 n/a Continuity
No. 2 & 22 n/a Continuity
No. 2 & 15 n/a Continuity
No. 2 & 20 n/a Continuity
No. 2 & 8 Disconnect O2 sensor, ground Green wire Continuity
No. 2 & 8 Reconnect O2 sensor Infinity ohms
No. 10 & 12 n/a 17.5-21.5 ohms
No. 14 & 17 n/a Less than 1K ohms
No. 17 & 18 n/a Greater than 4K ohms
No. 2 & 21 (Temperature Sensor) See Temp. Sensor Testing (2)
(1) TESTING CONDITIONS: Disconnect CIS-E ECU connector with ignition off. Set multimeter ohm scale.
(2) Reading of 6k/ohms at 32°F (0°C). Reading of 2.5k/ohms at 68°F (20°C). Reading of 300 ohms at 176°F (80°C). If readings are incorrect, check ground wire. If wiring is good, replace temperature sensor.
FOX CIS-E INJECTION - VOLTAGE CHECKS

Voltmeter Between Terminals Test Conditions (1) Specifications
No. 1 & 2 Ignition on Battery voltage
No. 2 & 24 Operate Starter Minimum 8 Volts
(1) TESTING CONDITIONS: Disconnect CIS-E ECU connector with ignition off. Remove and ground high tension lead (from coil) at distributor cap. Set multimeter to 20-volt DC scale.
FOX CIS-E INJECTION - RESISTANCE CHECKS

Ohmmeter Between Terminals Test Conditions (1) Specifications
No. 2 & 15 Ground Connection Reading of zero ohms
No. 9 & 15 Ground Connection Reading of zero ohms
No. 7 & 8 O2 Sensor Shield Reading of zero ohms
No. 2 & 8 O2 Sensor & Wiring Reading of zero ohms with Green O2 lead disconnected and grounded. If not, Green wire has open.
No. 2 & 8 O2 Sensor & Wiring Reading of infinity ohms with Green O2 lead connected to harness. If not, O2 is defective and should be replaced.
No. 10 & 12 Differential Pressure Reg. & Wiring Reading of 17.5-21.5 ohms. If not, check wire 10 or 12 for open. If wires are good, differential pressure regulator is defective and should be replaced.
No. 14 & 17 Potentiometer & Wiring Reading of less than 1000 ohms with airflow sensor plate in rest position. If not, check wires 14, 17, and 18 for open. If wires are good, adjust or replace potentiometer.
No. 17 & 18 Potentiometer & Wiring Reading of more than 4000 ohms. If not, check wires 14, 17, and 18 for open. If wires are good, adjust or replace potentiometer.
No. 2 & 21 Temperature Sensor & Wiring Reading of 2.5k ohms at 68°F (20°C). Lower ohm reading below 68°F or higher above 68°F. If readings are incorrect, check ground line (wire 21) between intake manifold and ECU. If wiring is good, temp. sensor is defective and should be replaced.
(1) TESTING CONDITIONS: Always disconnect ECU with ignition off. Disconnect main ECU connector behind glove box. Wiring connectors on temperature sensor, potentiometer, and differential pressure regulator must be connected. Set multimeter to 20k ohm scale. Prevent ohmmeter damage by checking ONLY terminals listed.
QUANTUM & QUANTUM SYNCRO VOLTAGE CHECKS

Voltmeter Between Terminals Test Conditions (1) Specifications
No. 1 & 2 Voltage Supply To ECU Battery voltage with ignition on. If not, check fuse 24. If fuse good, check open ground circuit between intake manifold and ECU.
No. 2 & 24 Voltage Supply From Starter Minimum of 8 volts with starter cranking. If not, check wiring from starter to ECU. If wiring good, check starter solenoid.
(1) TESTING CONDITIONS: Disconnect and ground high tension lead (from coil) at distributor cap. Unplug ECU connector with ignition off. Set multimeter to 20-volt DC scale.
QUANTUM & QUANTUM SYNCRO RESISTANCE CHECKS

Ohmmeter Between Terminals Test Conditions (1) Specifications
No. 2 & 22 Ground Bridge Reading of zero ohms. If not, check for open in bridge across terminals.
No. 2 & 15 Ground Bridge Reading of zero ohms. If not, check for open in bridge across terminals.
No. 7 & 8 O2 Sensor Wire Reading of infinity ohms. If not, check for open circuit in O2 sensor lead.
No. 2 & 8 O2 Sensor Wiring Reading of zero ohms with Green O2 sensor lead unplugged and grounded. If not, check for open in circuit in Green O2 sensor lead.
No. 10 & 12 Differential Pressure Reg. & Wiring Reading of 17.5-21.5 ohms. If not, check for open in circuit between regulator and ECU. If wiring is good, replace differential pressure regulator.
No. 14 & 17 Potentiometer & Wiring Reading below 12 k/ohms with airflow sensor plate in rest position and altitude sensor unplugged. If not, check wiring to terminals No. 14 and 17 for opens. If wiring is good, adjust or replace airflow sensor plate potentiometer.
No. 17 & 18 Potentiometer & Wiring Reading above 35 k/0hms with airflow sensor plate in rest position and altitude sensor unplugged. If not, check wiring to terminals No. 14 and 17 for opens. If wiring is good, adjust or replace airflow sensor plate potentiometer.
No. 18 & 14 Altitude Sensor Reading of 21-26 k/ohms with potentiometer unplugged. If not, check for open circuit in wiring. If wiring is good, replace altitude sensor.
No. 11 & 14 Altitude Sensor Reading of 200-38,000 ohms with potentiometer unplugged. If not, check for open circuit in wiring. If wiring is good, replace altitude sensor.
No. 21 & 2 Temperature Sensor Reading of 2.5 k/ohms at 68°F (20°C). Resistance reading should be higher at lower temperatures and lower at higher temperatures. If not, check for open circuit in wiring. If wiring is good, replace temperature sensor.
No. 1 & 5 Full Throttle Switch Reading of zero ohms with switch in full throttle position. Reading of infinity with full throttle switch in closed position. If not, check wiring for open circuit. If wiring is good, adjust or replace full throttle switch.
No. 1 & 13 Idle Switch Reading of zero ohms with switch in idle position. Reading of infinity with switch in any open throttle position. If not, check wiring for open circuit. If wiring is good, adjust or replace idle switch.
(1) TESTING CONDITIONS: Disconnect and ground high tension lead at ignition distributor end. Unplug ECU connector with ignition off. Set multimeter to 20-k/ohm scale. Prevent ohmmeter damage by checking ONLY terminals listed.
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