IAB System Inspection
- IAB control solenoid valve is located on top of intake manifold. Start and idle engine. Disconnect vacuum hose from IAB control diaphragm. See Fig 1 . Connect vacuum gauge to hose. If vacuum exists, go to step 7). If vacuum does not exist, go to next step.
- Remove vacuum hose from IAB vacuum storage tank. If vacuum is present, go to next step. If vacuum is absent, repair vacuum hose between vacuum source and vacuum tank.
- Turn ignition off. Unplug 2-pin connector from IAB control solenoid valve. Turn ignition on. Measure voltage between solenoid harness connector terminals. If battery voltage does not exist, go to next step. If battery voltage exists, Replace IAB control solenoid valve.
- With ignition on, measure voltage between Black/Yellow wire at IAB control solenoid harness connector and body ground. If battery voltage exists, go to step 6). If battery voltage does not exist, repair open in Black/Yellow wire between IAB solenoid harness connector and ECM fuse No. 4 located in underdash fuse box.
- Turn ignition off. Check for continuity between Black wire at IAB solenoid valve harness connector and body ground. If continuity exists, substitute a known-good PCM and recheck for symptom. If continuity does not exist, repair open ground wire between IAB solenoid valve harness connector and chassis ground point.
- Turn ignition on. Connect jumper wire between PCM terminals A9 and A26. See Fig 1 . If solenoid clicks when jumper wire is connected, substitute a known-good PCM and recheck operation. If solenoid valve does not click, repair open circuit between harness connector Pink/Blue wire and PCM terminal A17.
- Increase engine speed to 5000 RPM. Check for vacuum at IAB control diaphragm hose. If there is no vacuum, system is okay. If vacuum exists, unplug 2-pin connector from IAB control solenoid valve. If vacuum still exists, replace IAB control solenoid valve. If vacuum does not exist, check IAB control solenoid wires for short to power or ground. If wires are okay substitute a known-good PCM and recheck operation.