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Home >> Oldsmobile >> 1998 >> Regency >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control Systems Tests W/Codes >> Diagnostic Trouble Codes >> DTC P1673 - Engine Hot Light Control Circuit >> Diagnostic Procedures
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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 off. Disconnect PCM harness connector. Turn ignition on. Check voltage between ground and ENGINE HOT light control circuit at PCM harness connector. If battery voltage is present, go to next step. If battery voltage is not present, go to step 6).
  3. Check current between ground and ENGINE HOT light control circuit at PCM harness connector. Monitor reading for at least 2 minutes. If current reads between .05-.50 amp. go to step 11). If current does not read between .05-.50 amp, go to next step.
  4. Turn ignition off. Disconnect instrument panel connector. Leave PCM connector disconnected. Turn ignition on. Check voltage between ground and ENGINE HOT control circuit. If DVOM reads zero volts, go to step 10). If DVOM does not read zero volts, go to next step.
  5. Locate and repair short to voltage in ENGINE HOT light control circuit. After repairs, go to step 15).
  6. Check ignition feed fuse for instrument panel indicators. If fuse is blown, go to next step. If fuse is okay, go to step 8).
  7. Locate and repair short to ground in ignition feed circuit for instrument panel indicators. Replace fuse. After repairs, go to step 15).
  8. Turn ignition off. Disconnect instrument cluster. Turn ignition on. Check voltage between ground and ignition feed circuit for instrument cluster indicators. If battery voltage is present, go to next step. If battery voltage is not present, go to step 13).
  9. Check ENGINE HOT light control circuit for open or short to ground. Repair as necessary. After repairs, go to step 15). If circuit is okay, go to step 13).
  10. Check ENGINE HOT light control circuit and instrument panel indicators ignition feed circuit for poor connection at instrument panel and PCM. Repair as necessary. After repairs, go to step 15). If connections are okay, diagnose or repair instrument panel. See INSTRUMENT PANEL article in ACCESSORIES/SAFETY EQUIPMENT section.
  11. Turn ignition off. Reconnect PCM harness connector. Disconnect instrument cluster connector. Turn ignition on. Connect test light between ENGINE HOT light control circuit and ignition feed circuit at instrument panel harness connector. Using scan tool, cycle ENGINE HOT light on and off. If test light flashes on and off, see DIAGNOSTIC AIDS. If test light does not flash on and off, go to next step.
  12. Check ENGINE HOT light control circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 15). If connection is okay, go to step 14).
  13. Locate and repair open in ignition feed control circuit to instrument panel indicators. After repairs, go to step 15).
  14. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  15. Using scan tool, read and record FAIL RECORDS data, and clear DTCs. Operate vehicle within conditions noted in FAIL RECORDS data. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step 2). If scan tool does not display that this DTC FAILED THIS IGN, repair is complete.
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