Upstream Solenoid

Connect a voltmeter between light blue wire of solenoid and ground (using jumper wire if required). With ignition "ON", battery voltage should be present. If not, check for battery voltage at dark blue wire. If voltage is present at dark blue wire, replace solenoid; if not, check for short in solenoid voltage circuit.
Start engine and idle at 700 RPM. One volt should register on voltmeter. Accelerate engine from idle to 3000 RPM for 1-2 seconds. During acceleration period, battery voltage should be indicated. One volt should be indicated at idle. If system does not perform as stated, check Open Loop 2 system and replace if necessary. Refer to Computerized Emission Control in AMERICAN MOTORS Section.
If vacuum switches and Open Loop 2 operate properly, replace upstream solenoid. If voltmeter indication does not change, locate short between solenoid and Open Loop 2 switch.

Fig 1: AMC Air Guard System (Federal Models)
Courtesy of AMERICAN MOTORS/RENAULT CORP.

Fig 2: AMC Air Guard System (California Models)
Courtesy of AMERICAN MOTORS/RENAULT CORP.