Concord L6-258 4.2L VIN C 2-bbl (1982)
Upstream Solenoid: Testing and Inspection
1. Connect one lead of voltmeter to light blue wire at rear of upstream solenoid and the other lead to ground.
2. Turn ignition switch on, do not start engine. Voltmeter should indicate battery voltage. If not, check for battery voltage at dark blue wire. If battery
voltage is indicated at dark blue wire, replace solenoid. If battery voltage is not indicated at dark blue wire, check for short or open in solenoid
voltage circuit.
3. Start engine and idle at 700 rpm. Voltmeter should indicate about 1 volt.
4. Accelerate engine from idle to about 3,000 rpm for two seconds. Voltmeter should indicate battery voltage during acceleration and return to about
1 volt when engine returns to idle.
5. If system operation is not as described in step 4:
a. Disconnect open loop switch electrical connector. Connect one lead of test lamp to battery positive terminal and other lead to Open Loop 2 pin
(blue wire).
b. When manifold vacuum is present at Open Loop 2 switch nipple, lamp should not go on.
c. Disconnect vacuum hose. Lamp should go on. If not, replace Open Loop 2 switch assembly.
d. If vacuum switches are operating normally, replace upstream solenoid and connect all connections, hoses, etc.
6. Accelerate engine as described in step 4 and observe voltmeter for proper operation. If voltmeter indication does not change, locate short circuit in
harness between upstream solenoid and Open Loop 2 switch.
