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DTC P1685: Invalid Skim Key: Testing

  1. Turn ignition on. Using scan tool, read PCM DTCs. If DTC P1685 is displayed and STARTS SINCE SET counter is equal to zero, go to next step. If DTC P1685 is not displayed and STARTS SINCE SET counter is not equal to zero, go to step  7 .
  2. Using scan tool, attempt to communicate with SKIM. If scan tool communicates with SKIM, go to next step. If scan tool does not communicate with SKIM, go to BUS +/- SIGNAL OPEN FROM SKIM under COMMUNICATIONS under SYSTEM TESTS in BODY CONTROL MODULES - PT CRUISER article in ACCESSORIES & EQUIPMENT.
  3. Using scan tool, check for SKIM DTCs. If no SKIM DTCs are present, go to next step. If any DTCs are present, repair SKIM DTCs before continuing with this test. See BODY CONTROL MODULES - PT CRUISER article in ACCESSORIES & EQUIPMENT.
  4. Using scan tool, display Vehicle Identification Number (VIN) that is programmed into PCM. If VIN is programmed into PCM, go to next step. If VIN has not been programmed into PCM, use scan tool and program VIN into PCM.
  5. Using scan tool, display VIN that is programmed into PCM. If correct VIN is displayed, go to next step. If correct VIN is not displayed, replace PCM.
  6. Turn ignition off. Replace SKIM and program new SKIM. See REMOVAL & INSTALLATION in BODY CONTROL MODULES - PT CRUISER article in ACCESSORIES & EQUIPMENT. Start engine. Using scan tool, read PCM DTCs. If DTC P1685 resets, replace PCM. If DTC P1685 does not reset, test is complete.
  7. DTC P1685 may have been set if SKIM was disconnected or recently replaced. All customer's ignition keys for this vehicle must be tested at this time. Turn ignition on. Using scan tool, verify correct VIN is programmed in PCM and SKIM. Turn ignition off and remove ignition key. Using another customer key, turn ignition on and crank engine. Using scan tool, read PCM DTCs. If DTC P1685 is displayed and STARTS SINCE SET counter is equal to zero, replace ignition key. If DTC P1685 is not displayed and STARTS SINCE SET counter is not equal to zero, test is complete. If DTC P1685 cannot be reset, there may have been a theft attempt.
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