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IAB System Inspection

  1. IAB control solenoid valve is located on top of intake manifold. Start engine and allow to idle. Disconnect IAB control diaphragm vacuum hose. Check for vacuum at hose. See Fig 1 . If vacuum exists, go to step 6). If vacuum does not exist, go to next step.
  2. Remove vacuum hose from IAB vacuum tank. If vacuum exists at vacuum tank, go to next step. If vacuum does not exist at vacuum tank, repair blockage or vacuum leak between intake manifold and vacuum tank.
  3. Turn ignition off. Disconnect IAB control solenoid valve 2-pin connector. Turn ignition on. Measure voltage between solenoid valve connector terminals No. 1 (Pink/Blue wire) and No. 2 (Black/Yellow wire). If battery voltage is not present, go to next step. If battery voltage is present, replace IAB control solenoid valve.
  4. Ensure ignition is on. Measure voltage between ground and solenoid valve connector terminal No. 2 (Black/Yellow wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open in Black/Yellow wire between IAB control solenoid valve and ECM fuse No. 4 (20-amp), located in underdash fuse box.
  5. Connect a fused jumper wire between PCM 26-pin connector terminals No. 9 (Pink/Black wire) and No. 26 (Brown/Black wire). See Figure . If solenoid valve does not click when jumper wire is connected, repair open in Pink/Blue wire between IAB control solenoid valve and PCM. See WIRING DIAGRAMS article. If solenoid clicks when jumper wire is connected, substitute a known good PCM, then recheck. If symptom or indication goes away, replace original PCM.
  6. Increase engine speed to more than 5000 RPM. Check for vacuum at IAB control diaphragm hose. If vacuum does not exist, system is okay. If vacuum exists, go to next step.
  7. Disconnect IAB control solenoid valve 2-pin connector. Check for vacuum at IAB control diaphragm hose. If vacuum exists, replace IAB control solenoid valve. If vacuum does not exist, go to next step.
  8. Turn ignition off. Disconnect PCM 26-pin connector. Check for continuity between ground and IAB control solenoid valve connector terminal No. 1 (Pink/Blue wire). If continuity exists, repair short in Pink/Blue wire between PCM 26-pin connector terminal No. 9 and IAB control solenoid valve. If continuity does not exist, substitute a known good PCM, then recheck. If symptom or indication goes away, replace original PCM.
    Fig 1: Identifying IAB System Components
    G96I10064Courtesy of AMERICAN HONDA MOTOR CO., INC.
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