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Powertrain Diagnostic System Check

NOTE: Check for applicable Technical Service Bulletins (TSB) before proceeding. Perform the following procedure only if a driveability complaint exists, or if you were sent here from another procedure or article. DO NOT turn ignition off during the following procedure or clear DTCs unless instructed to do so.
  1. Install scan tool. Turn ignition on, with engine off. Observe scan tool. If scan tool turns on, go to next step. If scan tool does not turn on, perform SCAN TOOL DOES NOT POWER UP under SYSTEM TESTS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  2. Using scan tool, attempt to establish communication with Electronic Brake Control Module (EBCM), Instrument Panel Cluster (IPC), Heating, Ventilation and Air Conditioning (HVAC), Powertrain Control Module (PCM) and Vehicle Theft Deterrent Module (VTD). If scan tool communicates with all control modules, go to next step. If scan tool does not communicate with any of control module, perform SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  3. Attempt to start engine. If engine starts and idles, go to next step. If engine does not start, go to NO START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
  4. Using scan tool, select DTC display function for EBCM, HVAC, IPC, PCM and VTD. If scan tool displays any DTCs, go to next step. If scan tool does not display any DTCs, go to step  9.
  5. Using scan tool, select CAPTURED INFO in order to store PCM DTC information. After storing DTC information, go to next step.
  6. If scan tool displays any "U" series DTCs, perform SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If scan tool does not display any "U" series DTCs, go to next step.
  7. If DTC P0601, P0602, P0604 or P1683 is set, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If DTC P0601, P0602, P0604 or P1683 is not set, go to next step.
  8. If DTC P0562, P0563, P1637 or P1638 is set, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If DTC P0562, P0563, P1637 or P1638 is not set, go to next step.
  9. If problem is transmission related, diagnose transmission. See appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS in appropriate lemon-25® TRANSMISSION SERVICE & REPAIR manual. If problem is not transmission related, go to next step.
  10. If problem is I/M testing related, go to INSPECTION/MAINTENANCE SYSTEM CHECK  under INSPECTION/MAINTENANCE PROCEDURES. If problem is not I/M testing related, go to next step.
  11. Check for cause of hard start, surges/chuggles, lack of power, sluggishness, or sponginess. Check for cause of detonation/spark knock, hesitation, sag, stumble, cuts out, misses, poor fuel economy, rough/unstable, or incorrect idle and stalling. Check for cause of dieseling, run-on, backfire, MIL inoperative, or MIL always on. If problem is found, repair as necessary. See appropriate TROUBLESHOOTING - NO CODES article. If no problem is found, problem is intermittent.
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