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Scan Tool Does Not Communicate With Class 2 Data Line

  1. Disconnect scan tool from DLC. Turn ignition to RUN. Check voltage with DVOM between DLC terminal Nos. 2 and 4. If voltage is greater than 7 volts, go to next step. If voltage is not greater than 7 volts, go to step  9.
  2. Turn ignition OFF. Disconnect C100. Check voltage with DVOM between DLC terminal Nos. 2 and 4. If voltage is not greater than 7 volts, go to next step. If voltage is greater than 7 volts, go to step  5.
  3. Turn ignition OFF. Connect C100. Disconnect EBCM connector C1. Check voltage with DVOM between DLC terminal Nos. 2 and 4. If voltage is greater than 7 volts, go to next step. If voltage is not greater than 7 volts, go to step  17.
  4. Turn ignition OFF. Disconnect PCM/VCM. Check voltage with DVOM between DLC terminal Nos. 2 and 4. If voltage is greater than 7 volts, go to step  7. If voltage is not greater than 7 volts, go to step  17.
  5. Turn ignition OFF. Disconnect EVO/Passlock™ module. Check voltage with DVOM between DLC terminal Nos. 2 and 4. If voltage is greater than 7 volts, go to next step. If voltage is not greater than 7 volts, go to step  17.
  6. Turn ignition OFF. Disconnect transfer case shift module connector C1. Check voltage with DVOM between DLC terminal Nos. 2 and 4. If voltage is greater than 7 volts, go to step  8. If voltage is not greater than 7 volts, go to step  17.
  7. Repair short to voltage in Purple 1807 circuit wiring between C100 and EBCM and PCM/VCM. Perform diagnostic system check for EBCM and PCM/VCM. See DIAGNOSTIC SYSTEM CHECK in ANTI-LOCK BRAKES and ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in SELF DIAGNOSTICS - GASOLINE or ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in SELF DIAGNOSTICS - DIESEL in TESTING & DIAGNOSTICS in ENGINE PERFORMANCE.
  8. Repair short to voltage in Purple 1807 circuit wiring between DLC and EVO/Passlock™ module, C100 and transfer case shift module. Connect C100. Perform diagnostic system check for EVO/Passslock™ module and transfer case shift module. See DIAGNOSTIC SYSTEM CHECK in ANTI-THEFT SYSTEMS article and TRANSFER CASE SYSTEM CHECK in TRANSFER CASE article in TRANSAXLE/TRANSMISSION.
  9. Turn the ignition OFF. Check for continuity with DVOM between ground and DLC terminal No. 2. If there is continuity, go to next step. If there is not continuity, perform diagnostic system check for all modules on 1807 circuit. See appropriate DIAGNOSTIC SYSTEM CHECK section or article.
  10. Disconnect C100. Check for continuity with DVOM between ground and DLC terminal No. 2. If there is not continuity, go to next step. If there is continuity, go to step  13.
  11. Reconnect C100. Disconnect EBCM connector C1. Check for continuity with DVOM between ground and DLC terminal No. 2. If there is continuity, go to next step. If there is not continuity, go to step  17.
  12. Disconnect the PCM/VCM. Check for continuity with DVOM between ground and DLC terminal No. 2. If there is continuity, go to step  15. If there is not continuity, go to step  17.
  13. Disconnect EVO/Passlock™ module. Check for continuity with DVOM between ground and DLC terminal No. 2. If there is continuity, go to next step. If there is not continuity, go to step  17.
  14. Disconnect transfer case shift control module connector C1. Check for continuity with DVOM between ground and DLC terminal No. 2. If there is continuity, go to step  16. If there is not continuity, go to step  17.
  15. Repair short to ground in Purple 1807 wiring between C100 and EBCM and PCM/VCM. Perform diagnostic system check for EBCM and PCM/VCM. See DIAGNOSTIC SYSTEM CHECK in appropriate ANTI-LOCK article in BRAKES and ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in SELF DIAGNOSTICS - GASOLINE or ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in SELF DIAGNOSTICS - DIESEL article in TESTING & DIAGNOSTICS in ENGINE PERFORMANCE.
  16. Repair short to ground in Purple 1807 wiring between DLC and EVO/Passlock™ module, C100 and transfer case shift control module. Connect C100. Perform diagnostic system check for EVO/Passlock™ module and transfer case shift control module. See DIAGNOSTIC SYSTEM CHECK in ANTI-THEFT SYSTEMS and TRANSFER CASE SYSTEM CHECK in TRANSFER CASE article in TRANSAXLE/TRANSMISSION.
  17. Replace module most recently disconnected. Perform diagnostic system check for all modules on 1807 circuit. See Appropriate DIAGNOSTIC SYSTEM CHECK in appropriate system article.
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