Automatic Idle Control Valve - Troubleshooting
88saab08FILE IN S.I. Man VOL. I
SEC. A-2,B-2 PG. 209
ISSUE 10/88-1081, 1082
SUBJECT: AUTOMATIC IDLE CONTROL VALVE TROUBLESHOOTING
APPLICATION: 900, 9000 MODELS WITH THE LH 2.2 OR 2.4 FUEL INJECTION SYSTEMS
Troubleshooting an automatic idle control (AIC) valve is easily accomplished using a digital volt-ohmmeter (VOM). Listed below are the procedures to troubleshoot the AIC valves used in LH 2.2 and 2.4 fuel injection systems.
Tool: Digital volt-ohm-meter P/N 02 80 719
LH 2.2 AIC Valve Troubleshooting
NOTE
Resistance measurements are strongly affected by temperature. The valve should be checked at room temperature. The engine should not be run before starting this troubleshooting sequence.
1. Unplug the connector from the AIC valve.
FIGURE 1:
2. Connect a digital VOM to the actuator terminal pins as shown in Figure 1 and check the actuator resistance.
3. If an intermittent fault is suspected, lightly tap the actuator while reading the resistance from the center pin to the two outer pins (pins 1 and 3).
4. If the resistance is incorrect, install a new AIC valve. If the resistance is correct, proceed to the "Operational Check" procedure.
LH 2.4 AIC Valve Troubleshooting
NOTE
Resistance measurements are strongly affected by temperature. The valve should be checked at room temperature. The engine should not be run before starting this troubleshooting procedure.
1. Unplug the connector from the AIC valve.
FIGURE 2 - LH 2.4 AIC VALVE TERMINALS.:
2. Check the AIC valve resistance by connecting a digital VOM across the terminals (Figure 2). The resistance should be 7 ohms +/- 5.
3. If the resistance is out of specification, install a new AIC valve. If the resistance is within specification, continue with step 4.
4. Perform the component and signal testing procedure in Service Manual Section 0 "News". valve should audibly open and close during the component test cycle. If the valve does not operate properly install a new valve.
5. As with the LH 2.2 AIC valve troubleshooting, you can plug the suspect valve into a normally operating LH 2.4 vehicle for a simple operational check (see Operational Check").
Operational Check for LH 2.2 or LH 2.4
1. Remove the suspect AIC valve (See Service Manual).
2. Start a normally functioning car with the appropriate fuel injection system and allow it to idle.
3. Unplug the connector from the AIC valve of the idling car.
FIGURE 3 - AIC VALVE CUTAWAY.:
4. Plug the suspect AIC valve into the harness connector of the idling test car. Do not connect the air hoses to the suspect AIC valve.
5. The valve should vibrate noticeably and the valve shutter should increase the port opening (Figure 3) as you slow the engine speed by unplugging an injector wire or cycling the AC. If the shutter binds and does not operate smoothly throughout its travel, the valve is faulty.
6. Turn off the engine. Unplug the suspect valve. Reconnect the harness connector to the test car's AIC valve.
7. If the suspect valve did not operate properly replace it-with a new valve (See Service Manual).
Warranty Information: For warranty claims, use Failure Code 24641-79-0-01-
01. The warranty labor allowance is Operation #24641 (0.2 hour) for removing and replacing an AIC valve. This includes time to make the above check. The resulting readings must be included in the claim's technical explanation.