LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Buick >> 1996 >> Roadmaster Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control Systems - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P0372 - Ignition High Resolution Circuit >> Diagnostic Procedures
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) System Check. After performing OBD system check, go to next step.
  2. Start and warm engine to normal operating temperature. Using scan tool, monitor high resolution signal. If scan tool displays signal as inactive, go to step 4). If scan tool displays signal as active, go to next step.
  3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within the conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME/FAILURE RECORDS as possible. Select DTC function, then enter DTC P0372. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see DIAGNOSTIC AIDS.
  4. Turn ignition off. Disconnect ignition system test connector. Turn ignition on. Using DVOM, check voltage on terminal "B" at PCM side of ignition test connector. If voltage is 5 volts, go to next step. If voltage is not as specified, go to step 8).
  5. Turn ignition off. Reconnect ignition test connector. Disconnect distributor connector. Turn ignition on. Using DVOM, check voltage on terminal "B" of distributor harness connector. If voltage is about 5 volts, go to step 11). If voltage is not as specified, go to next step.
  6. If voltage was greater than 5 volts, go to next step. If voltage was less than 5 volts, go to step 12).
  7. Repair short to voltage on high resolution signal circuit to ignition test connector. After repairs, go to step 14).
  8. If voltage was greater than 5 volts, go to step 10). If voltage was less than 5 volts, go to next step.
  9. Repair open or grounded high resolution circuit from ignition test connector to PCM. After repairs, go to step 14). If circuit is okay, go to step 13).
  10. Repair short to voltage on high resolution signal circuit from ignition test connector to distributor. After repairs, go to step 14).
  11. Repair faulty distributor connection or faulty distributor. After repairs, go to step 14).
  12. Repair open or grounded high resolution circuit from ignition test connector to distributor. After repairs, go to step 14). If circuit is okay, go to next step.
  13. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  14. Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0372. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step 2).
  15. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTC(s) are displayed, go to applicable DTC test.
scientia non olet · About LEMON Manuals