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Home >> Cadillac >> 1998 >> Eldorado Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P1575 - Extended Travel Brake Switch Circuit >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK , then go to next step.
  2. Turn ignition on. Using scan tool in ENGINE 1 mode, note EXT TRAVEL BRAKE display. If scan tool display indicates RELEASED, go to next step. If scan tool display does not indicate RELEASED, go to step 7).
  3. Depress brake pedal about half way. If scan display indicates APPLIED, fault is not present. See DIAGNOSTIC AIDS. If scan tool display does not indicate APPLIED, go to next step.
  4. Disconnect extended travel brake switch connector. If scan tool display indicates APPLIED, go to step 21). If scan tool display does not indicate APPLIED, go to next step.
  5. Store fluid life index as indicated on scan tool. Turn ignition off and wait 30 seconds, then disconnect PCM harness connector C1. Turn ignition on. Using DVOM, check voltage between ground and TCC brake switch input circuit terminal at PCM harness connector C1. If voltage is greater than .5 volt, go to next step. If voltage is not greater than .5 volt, go to step 19).
  6. Repair short to voltage between extended travel brake switch input circuit.
  7. Note TCC BRAKE SWITCH display on scan tool. If scan tool display indicates RELEASED, go to next step. If scan tool display does not indicate RELEASED, go to step 11).
  8. Disconnect extended travel brake switch harness connector. Using DVOM, check voltage between ground and extended travel brake switch terminal "C". If voltage reading is 10 volts or greater, go to next step. If voltage reading is not 10 volts or greater, go to step 17).
  9. Using jumper wire, jumper extended travel brake switch terminals 'C" and "D". If scan tool display indicates RELEASED, go to step 21). If scan tool display does not indicate RELEASED, go to next step.
  10. Store fluid index as indicated on scan tool. Turn ignition off and wait 30 seconds, then disconnect PCM harness connector C1. Turn ignition on. Using DVOM, check voltage between ground and TCC brake switch input circuit at PCM harness connector C1 terminal. If voltage reading is 10 volts or greater, go to step 13). If voltage reading is not 10 volts or greater, go to step 18).
  11. Check fuse to shift solenoid. If fuse is faulty, go to step 13). If fuse is okay, go to next step.
  12. Disconnect extended travel brake switch connector. Using DVOM, check voltage between ground and extended travel brake switch connector terminal "C". If voltage reading is 10 volts or greater, go to step 21). If voltage reading is not 10 volts or greater, go to step 16).
  13. Store fluid life index as indicated on scan tool. Turn ignition off and wait 30 seconds, then disconnect PCM harness connector C1. Using DVOM, individually check the resistance to all the extended travel switch connector terminals. If resistance is less than 100 ohms on any of the terminals, go to next step. If resistance is not less than 100 ohms on any of the terminals, go to step 15).
  14. Repair short in the circuits with low resistance. Replace fuse.
  15. Check for intermittent short to ground on both extended travel and TCC brake switch circuits. Repair as necessary. Replace fuse.
  16. Repair open in circuit to EBTCM.
  17. Repair open in circuit to shift solenoid fuse.
  18. Repair open in circuit between switch and EBTCM.
  19. Check terminal contact at PCM harness connector C1. Repair as necessary. If terminal contact is okay, go to next step.
  20. Replace PCM. Program replacement PCM using required equipment.
  21. Check for proper adjustment of extended travel brake switch. Adjust as necessary. If adjustment was not necessary, go to next step.
  22. Replace extended travel brake switch.
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