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Home >> Acura >> 1998 >> Integra GS-R, 4D Sedan >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Air Induction Systems >> Intake Air By-Pass (IAB) System >> IAB System Inspection (3.2TL)
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IAB System Inspection (3.2TL)

  1. IAB control solenoid valves are located at right front corner of engine compartment next to power steering fluid reservoir. IAB high and low control diaphragm valves are located at rear of engine. Ensure IAB valve shaft move smoothly and do not bind or stick. If necessary, clean linkage and shafts.
  2. If testing IAB low control valve, remove vacuum hose No. 2 from vacuum hose manifold. If testing IAB high control valve, remove vacuum hose No. 8 from vacuum hose manifold. On either low or high IAB control valve, connect vacuum pump to hose. Apply vacuum. Ensure that IAB control diaphragm valve holds vacuum. As vacuum is applied and released, IAB control diaphragm valve rod should move in and out. If IAB control diaphragm does not perform as specified, replace IAB control diaphragm valve and retest.
  3. Start engine and allow to idle. Remove vacuum hose No. 2 from IAB low control diaphragm. See Fig 1. Connect vacuum gauge to hose. If vacuum is present, go to step 8). If vacuum is not present, go to next step.
  4. Disconnect vacuum hose No. 4 at IAB low control solenoid valve. See Fig 1. Connect vacuum gauge to hose and check for vacuum. With engine at idle, if vacuum is present, go to next step. If vacuum is not present, check for a blockage or vacuum leak between IAB vacuum tank and intake manifold. Repair as necessary and recheck.
  5. Turn ignition off. Disconnect IAB control solenoid valve assembly 4-pin connector. Start engine and allow to idle. On all models, measure voltage between IAB control solenoid valve assembly connector Black/Yellow wire and Red/Blue wire terminals. If battery voltage is present, replace IAB low control solenoid valve. If voltage is not present, go to next step.
  6. Measure voltage between ground and IAB control solenoid valve assembly connector Black/Yellow wire terminal. If battery voltage is present, go to next step. If battery voltage is not present, repair open in Black/Yellow wire between solenoid valve connector and ECU (20-amp) fuse, located in underdash fuse/relay box.
  7. Turn ignition off. Check for continuity in Red/Blue wire between PCM 26-pin connector terminal No. 20 and IAB control solenoid valve connector. See Figure. If continuity does not exist, repair open in Red/Blue wire. If continuity exists, substitute a known good PCM, then recheck. If symptom or indication goes away, replace original PCM.
  8. With engine idling, disconnect vacuum hose No. 8 from IAB high control diaphragm. Connect vacuum gauge to hose. If vacuum is present, go to next step. If vacuum is not present, go to step 11).
  9. Increase engine speed to 3400 RPM. Check for vacuum at low control diaphragm hose No. 2. If vacuum is not present, go to next step. If vacuum is present, go to step 15).
  10. Increase engine speed to 4000 RPM. Check for vacuum at high control diaphragm hose No. 8. If vacuum is not present, system is okay. If vacuum is present, go to step 17).
  11. Disconnect vacuum hose No. 4 from IAB low control solenoid valve. See Fig 1. Connect vacuum gauge to hose and check for vacuum. With engine at idle, if vacuum is present, go to next step. If vacuum is not present, check for a blockage or vacuum leak between IAB vacuum tank and intake manifold. Repair as necessary and recheck.
  12. Turn ignition off. Disconnect IAB high control solenoid valve assembly 4-pin connector. Start engine and allow to idle. Measure voltage between IAB control solenoid valve assembly connector Black/Yellow wire and Yellow wire terminals. If battery voltage is not present, go to next step. If battery voltage is present, replace IAB high control solenoid valve.
  13. Measure voltage between ground and IAB control solenoid valve assembly connector Black/Yellow wire terminal. If battery voltage is present, go to next step. If battery voltage is not present, repair open in Black/Yellow wire between IAB solenoid valve assembly connector and ECU (20-amp) fuse.
  14. Turn ignition off. Check for continuity in Yellow wire between PCM 26-pin connector terminal No. 22 and IAB control solenoid valve assembly connector. See Figure. If continuity does not exist, repair open in Yellow wire. If continuity exists, substitute a known good PCM, then recheck. If symptom or indication goes away, replace original PCM.
  15. Disconnect IAB high control solenoid valve assembly 4-pin connector. With engine speed at 3400 RPM, if vacuum is not present, go to next step. If vacuum is present, replace IAB low control solenoid valve.
  16. Turn ignition off. Disconnect PCM 26-pin connector. See Figure. Check continuity between ground and PCM 26-pin connector terminal No. 20 (Yellow wire). If continuity exists, repair short in Yellow wire between PCM and IAB control solenoid valve assembly. If continuity does not exist, substitute a known good PCM, then recheck. If symptom or indication goes away, replace original PCM.
  17. Disconnect IAB high control solenoid valve assembly 4-pin connector. With engine speed at 4000 RPM, if vacuum is not present, go to next step. If vacuum is present, replace IAB high control solenoid valve.
  18. Turn ignition off. Disconnect PCM 26-pin connector. See Figure. Check continuity between ground and PCM 26-pin connector terminal No. 22 (Yellow wire). If continuity exists repair short in yellow wire. 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 Control System (3.2TL)
    G97D06008Courtesy of AMERICAN HONDA MOTOR CO., INC.
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