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HOMESERVICE MANUALSOLDSMOBILE1998ACHIEVA 3.1 M, 4T40E/MN4REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 13 (BODY CONTROL MODULE)DIAGNOSTIC TESTSDTC B1492: GENERATOR "F" TERMINAL LOWTESTING
1998 Oldsmobile Achieva 3.1 M, 4T40E/MN4

DTC B1492: Generator "F" Terminal Low: Testing

1998 Oldsmobile Achieva 3.1 M, 4T40E/MN4SECTION Testing
WARNING: This page is about a different car, the 1998 Oldsmobile Cutlass and 1998 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in BFC DIAGNOSTIC SYSTEM CHECK  .
  2. On 2.4L, disconnect PCM Blue 80-pin connector C1, terminal No. 53 (Gray wire). On 3.1L, disconnect PCM Clear 80-pin connector C2, terminal No. 62 (Gray wire). Disconnect generator connector. On 2.4L, use DVOM to check resistance between PCM harness connector C1, terminal No. 53 (Gray wire) and ground. On 3.1L, use DVOM to check resistance between PCM harness connector C2, terminal No. 62 (Gray wire) and ground. If resistance is infinite, go to step 4). If resistance is not infinite, go to next step.
  3. Repair short to ground in Gray wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 10).
  4. On 2.4L, use DVOM to check resistance between PCM harness connector C1, terminal No. 53 (Gray wire) and generator harness connector terminal "C" (Gray wire). On 3.1L, use DVOM to check resistance between PCM harness connector C2, terminal No. 62 (Gray wire) and generator harness connector terminal "C" (Gray wire). If resistance is 0-2 ohms, go to step 6). If resistance is not 0-2 ohms, go to next step.
  5. Repair open in Gray wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 10).
  6. Connect a fused jumper wire between generator terminals "C" (Gray wire) and "D" (Orange wire). Start engine. Using scan tool, read generator PWM. If scan tool displays greater than 50 percent, go to next step. If scan tool does not display greater than 50 percent, go to step 8).
  7. Start engine. Repeatedly reconnect and disconnect generator connector. Using scan tool, read PCM generator PWM status. If PCM generator PWM oscillates, go to step 10). If PCM generator PWM does not oscillate, go to step 9).
  8. Replace PCM. See REMOVE/INSTALL/OVERHAUL article in ENGINE PERFORMANCE section. Go to step 10).
  9. Replace generator. See GENERATOR & REGULATOR article in ELECTRICAL section. Go to next step.
  10. Clear DTCs. Perform BFC DIAGNOSTIC SYSTEM CHECK  .


  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in BFC DIAGNOSTIC SYSTEM CHECK  .
  2. On 2.4L, disconnect PCM Blue 80-pin connector C1, terminal No. 53 (Gray wire). On 3.1L, disconnect PCM Clear 80-pin connector C2, terminal No. 62 (Gray wire). Disconnect generator connector. On 2.4L, use DVOM to check resistance between PCM harness connector C1, terminal No. 53 (Gray wire) and ground. On 3.1L, use DVOM to check resistance between PCM harness connector C2, terminal No. 62 (Gray wire) and ground. If resistance is infinite, go to step 4). If resistance is not infinite, go to next step.
  3. Repair short to ground in Gray wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 10).
  4. On 2.4L, use DVOM to check resistance between PCM harness connector C1, terminal No. 53 (Gray wire) and generator harness connector terminal "C" (Gray wire). On 3.1L, use DVOM to check resistance between PCM harness connector C2, terminal No. 62 (Gray wire) and generator harness connector terminal "C" (Gray wire). If resistance is 0-2 ohms, go to step 6). If resistance is not 0-2 ohms, go to next step.
  5. Repair open in Gray wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 10).
  6. Connect a fused jumper wire between generator terminals "C" (Gray wire) and "D" (Orange wire). Start engine. Using scan tool, read generator PWM. If scan tool displays greater than 50 percent, go to next step. If scan tool does not display greater than 50 percent, go to step 8).
  7. Start engine. Repeatedly reconnect and disconnect generator connector. Using scan tool, read PCM generator PWM status. If PCM generator PWM oscillates, go to step 10). If PCM generator PWM does not oscillate, go to step 9).
  8. Replace PCM. See REMOVE/INSTALL/OVERHAUL article in ENGINE PERFORMANCE section. Go to step 10).
  9. Replace generator. See GENERATOR & REGULATOR article in ELECTRICAL section. Go to next step.
  10. Clear DTCs. Perform BFC DIAGNOSTIC SYSTEM CHECK  .
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