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DTC P1634: Generator Terminal B Circuit Open: Testing

NOTE: Check for service bulletins and on-line information.
  1. Turn ignition on. Using scan tool, monitor ALTT V and B+ PIDs. Start engine. If ALTT V PID is more than 17 volts and B+ PID is less than 11 volts, go to next step. If ALTT V PID is 17 volts or less and B+ PID is more than 11 volts, problem is intermittent. See TROUBLE SHOOTING - NO CODES article.
  2. Turn ignition off. Check battery. If battery is okay, go to next step. If battery is faulty, replace battery and go to step  4 .
  3. Turn ignition off. Check generator terminal "B" nut and positive battery terminal. If both connections are tight, go to next step. If any connection is loose, tighten and go to step  4 .
  4. Disconnect both battery terminals. Disconnect generator terminal "B" (Black/Red wire). Check continuity between generator harness connector "B" and positive battery terminal connector. If continuity is present, go to next step. If continuity is not present, repair open circuit between generator harness connector "B" and positive battery terminal connector. After repair, go to next step.
  5. Reconnect all components. Using scan tool, clear DTCs. Turn ignition off. Start engine. Recheck DTCs. If same DTC is present, replace PCM and go to next step. PCM is mounted to passenger floor, behind glove box. If same DTC is not present, go to next step.
  6. Perform after repair procedure. See AFTER REPAIR PROCEDURE  . If no DTC is present, testing is complete. If any DTC is present, go to appropriate test for diagnosis and repair.
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