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Generator Control System Test: Prelude

CAUTION: On Prelude, when substituting a known-good ECM, immobilizer code must be rewritten using Honda PGM tester, or engine will not start.
  1. Turn ignition off. Disconnect 4-pin generator harness connector. Start engine and turn on headlights (high beam). Check voltage between generator 4-pin harness connector terminal No. 2 (White/Green wire) and battery positive terminal. See WIRING DIAGRAMS  . If voltage reading is one volt or less, go to next step. If voltage reading is not one volt or less, go to step  3 .
  2. Turn ignition and headlights off. Disconnect 32-pin ECM harness connector. Check continuity in White/Green wire between ECM harness connector terminal No. 19 and generator harness connector terminal No. 2. If continuity exists, test and repair generator components. If continuity does not exist, repair open White/Green wire between generator and ECM.
  3. Turn ignition and headlights off. Disconnect 32-pin ECM harness connector. Check continuity between body ground and ECM harness connector terminal No. 19 (White/Green wire). If continuity exists, repair short in White/Green wire between ECM and generator harness connectors. If continuity does not exist, go to next step.
  4. Substitute a known-good ECM. Recheck system operation. If specified voltage is now available, replace original ECM.
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