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HOMESERVICE MANUALSOLDSMOBILE1998ACHIEVA 3.1 M, 4T40E/MN4REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 13 (BODY CONTROL MODULE)DIAGNOSTIC TESTSDTC B1493: GENERATOR "F" TERMINAL HIGHTESTING
1998 Oldsmobile Achieva 3.1 M, 4T40E/MN4

DTC B1493: Generator "F" Terminal High: 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. Turn ignition switch to RUN position, with engine off. Disconnect generator connector. Using scan tool, read generator PWM. If scan tool displays zero percent, go to next step. If scan tool does not display zero percent, go to step 5).
  3. Reconnect generator connector. Start engine. Using scan tool, read generator PWM from PCM. 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 5).
  4. Replace generator. See GENERATOR & REGULATOR article in ELECTRICAL section. Go to next step.
  5. Disconnect generator connector. On 2.4L, disconnect PCM Blue 80-pin connector C1. On 3.1L, disconnect PCM Clear 80-pin connector C2. On all models, use DVOM to check voltage at generator terminal "C" (Gray wire). If reading is zero volts, go to step 7). If reading is not zero volts, go to next step.
  6. Repair short to battery in Gray wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 8).
  7. Replace PCM. See REMOVE/INSTALL/OVERHAUL article in ENGINE PERFORMANCE section. Go to next step.
  8. 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, BFC DIAGNOSTIC SYSTEM CHECK  .
  2. Turn ignition switch to RUN position, with engine off. Disconnect generator connector. Using scan tool, read generator PWM. If scan tool displays zero percent, go to next step. If scan tool does not display zero percent, go to step 5).
  3. Reconnect generator connector. Start engine. Using scan tool, read generator PWM from PCM. 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 5).
  4. Replace generator. See GENERATOR & REGULATOR article in ELECTRICAL section. Go to next step.
  5. Disconnect generator connector. On 2.4L, disconnect PCM Blue 80-pin connector C1. On 3.1L, disconnect PCM Clear 80-pin connector C2. On all models, use DVOM to check voltage at generator terminal "C" (Gray wire). If reading is zero volts, go to step 7). If reading is not zero volts, go to next step.
  6. Repair short to battery in Gray wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 8).
  7. Replace PCM. See REMOVE/INSTALL/OVERHAUL article in ENGINE PERFORMANCE section. Go to next step.
  8. Clear DTCs. Perform BFC DIAGNOSTIC SYSTEM CHECK  .
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
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  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
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