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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 should be disconnected at ignition distributor end and connected to ground. Use Digital Multimeter (US 1119).

5000S 5-CYLINDER VOLTAGE CHECKS (1)

Voltmeter Between Terminals Components Checked Specifications
No. 1 & No. 2 Voltage Supply To ECU Battery voltage with ignition on. If not check fuse 24. If good check open ground circuit between intake manifold & ECU.
No. 2 & No. 24 Voltage Supply From Starter Minimum reading of 8 volts w/ 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 at ignition distributor end. Unplug ECU connector with ignition off. Set multimeter to 20 volts DC scale.
5000S 5-CYLINDER RESISTANCE CHECKS (1)

Ohmmeter Between Terminals Components Checked Specifications
No. 2 & No. 22 Ground Bridge Reading of 0 ohms.If not check for open in bridge across terminals.
No. 2 & No. 15 Ground Bridge Reading of 0 ohms.If not check for open in bridge across terminals.
No. 7 & No. 8 O2 Sensor Wire Reading of infinity ohms. If not check for open circuit in O2 sensor lead.
No. 2 & No. 8 O2 Sensor Wiring Reading of 0 ohms w/ Green O2 sensor lead unplugged grounded If not check for open in circuit in Green O2 sensor lead
No. 10 & No. 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 & No. 17 Potentiometer & Wiring Reading below 12,000 ohms with airflow sensor plate in rest position and altitude sensor unplugged. If not check wirings to terminals 14 & 17 for opens. If wiring is good, adjust or replace airflow sensor plate potentiometer.
No. 17 & No. 18 Potentiometer & Wiring Reading above 35,000 ohms with airflow sensor plate in rest position and altitude sensor unplugged. If not check wirings to terminals 14 & 17 for opens. If wiring is good, adjust or replace airflow sensor plate potentiometer.
No. 18 & No. 14 Altitude Sensor Reading of 21-26,000 ohms with potentiometer unplugged. If not check for open circuit in wiring. If wiring is good, replace altitude sensor
No. 11 & No. 14 Altitude Sensor Reading of 200-38,000 ohms w/ potentiometer unplugged. Ifnot check for open circuit in wiring. If wiring is good, replace altitude sensor
No. 21 & No. 2 Temperature Sensor Reading of 2500 ohms at 68°F (20°C). Reading should be higher at lower temperatures & lower at higher temperatures. If not, check for open circuitin wiring. If wiring is good, replace temperature sensor
No. 1 & No. 5 Full Throttle Switch Reading of 0 ohms with switch in full throttle position. Reading should be infinity ohms w/ full throttle switch closed. If not, check for open circuit If wiring is good, adjust or replace full throttle switch.
No. 1 & No. 13 Idle Switch Reading of 0 ohms with switch in idle position. Reading should be infinity ohms with switch in any open throttle position. If not, check 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.
4000S 4-CYLINDER VOLTAGE CHECKS (1)

Voltmeter Between Terminals Components Checked Specifications
No. 1 & No. 2 Voltage Supply To ECU Battery voltage with ignition on. If not check fuse 24. If good check open circuit in wiring.Check ground connection on cold start valve.
No. 1 & No. 15 Ground Connection 2/15 Battery voltage with ignition on. If not check ground connection bridge in multi- port connector
No. 1 & No. 9 (2) Ground Connection 15/9 Battery voltage with ignition on. If not check ground connection bridge in multi- port connector
No. 1 & No. 22 (3) Ground Connection 15/22 Battery voltage with ignition on. If not check ground connection bridge in multi- port connector
No. 2 & No. 24 Wiring Between Starter & ECU Minimum 8 volts with starter cranking. If not check wiring for open.
(1) TESTING CONDITIONS : Disconnect and ground high tension lead at ignition distributor end. Unplug ECU connector with ignition off. Set multimeter to 20,000-ohm scale. Prevent Ohmmeter damage by checking ONLY terminals listed.
(2) No specifications given for testing altitude sensor, if equipped.
(3) Potentiometer terminals No. 1, 2 and 3 are connected respectively to terminals No. 18, 17 and 14 on ECU connector. On automatic transmissions only.
4000S 4-CYLINDER RESISTANCE CHECKS (1)

Ohmmeter Between Terminals Components Checked Specifications
No. 7 & No. 8 O(2) Sensor Wire Shield Reading should be infinity ohms. If not, check shielding for shorts.
No. 8 & No. 2 O(2) Sensor & Wiring Reading should be zero ohms with Green O(2) sensor lead unplugged and grounded. If not, check Green wire for open. Reading should be in- finity ohms with O(2) sensor lead connected. If not, O(2) sensor is defective and should be replaced.
No. 10 & No. 12 Differential Pressure Reg. & Wiring Reading should be 17.5-21.5 ohms. If not, check wires 10 and 12. If wiring is good, differential pressure reg- ulator is defective and should be replaced.
No. 14 & No. 17 Potentio- meter & Wiring (2) Reading of less than 1000 or more than 4 k/ohms with air- flow 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 & No. 18 Potentio- meter & Wiring (2) Reading of less than 1000 or more than 4 k/ohms with air- flow sensor plate in rest position. If not, check wires 14, 17 and 18 for open. If wires are good, adjust or replace potentiometer.
No. 21 & No. 2 Temperature Sensor & Wiring Reading of 2.5 k/ohms at 68°F (20°C). Resistance reading should be higher at lower temperatures and lower at higher temperatures (about 600 ohms with engine warmed up). If not, check for open circuit in wiring. If wiring is good, replace temperature sensor.
(1) TESTING CONDITIONS: Disconnect and ground high tension lead at ignition distributor end. Unplug ECU connector with ignition off. Set multimeter to 20,000-ohm scale. Prevent ohmmeter damage by checking ONLY TERMINALS LISTED.
(2) Potentiometer terminals No. 1, 2 and 3 are connected respectively to terminals No. 18, 17 and 14 on ECU connector.
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