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Home >> Oldsmobile >> 1998 >> Regency >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control Systems Tests W/Codes >> Diagnostic Trouble Codes >> DTC P1571 - Traction Control System Desired Torque Circuit >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. After performing OBD system check, go to next step.
  2. Turn ignition on. Using scan tool, read DESIRED TORQUE. If PWM is about 100 percent, go to step 4). If PWM is not as specified, go to next step.
  3. Turn ignition off. Disconnect Electronic Brake and Traction Control Module (EBTCM) connector. Turn ignition on. Using a DVOM, check voltage between engine ground and EBTCM harness connector desired torque PWM circuit. If voltage is 5 volts, go to next step. If voltage is not 5 volts, go to step 6).
  4. Turn ignition off. Connect ABS/TCS Pinout Box and Adapter (J39700-25) between EBTCM and EBTCM connector. Using DVOM in Hertz (Hz) scale, check frequency between engine ground and desired torque PWM circuit. Turn ignition on. If frequency is 120-135 Hz, go to next step. If frequency is not as specified, go to step 7).
  5. Using DVOM in duty cycle scale, check duty cycle between engine ground and desired torque PWM circuit. Turn ignition on, engine off. If duty cycle is 5-95 percent, go to step 9). If measured duty cycle is not as specified, go to step 7).
  6. Turn ignition off. Disconnect harness PCM. Turn ignition on. Check desired torque PWM circuit for open, short to ground or short to voltage. Repair as necessary . After repairs are complete, go to step 11). If circuit is okay, go to step 9).
  7. Check for faulty connection at EBTCM. Repair as necessary. After repairs, go to step 11). If connection is okay, go to next step.
  8. Replace EBTCM. After replacing EBTCM, go to step 11).
  9. Check for faulty connection at PCM. Repair as necessary. After repairs, go to step 11). If connection is okay, go to next step.
  10. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  11. Clear DTCs. Turn ignition on and observe DESIRED TORQUE PWM scan tool display. If scan tool displays about 100, repair is complete. If scan tool does not display about 100 percent, return to step 2)
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