P0602

P0602 is set when the PCM detects that it has not been programmed, has been programmed incorrectly, or is missing the VIN, calibration, or variant coding it expects. This is almost always a service-event code: it appears after a failed flash, after installing a used or remanufactured PCM that was not properly configured, or after a parts-store module that shipped with generic calibration. The cheapest first step is to read the current calibration ID and VIN from the PCM with a scan tool — if the VIN field is blank, all zeros, or does not match the dash VIN, the module simply needs to be programmed and configured with the correct OEM software (GM SPS, Ford FDRS/IDS, Chrysler wiTECH, etc.). Verify battery voltage stays above 13.5V during the entire reflash by connecting a dedicated programming-grade power supply, not a trickle charger, because a voltage dip mid-flash is what created many P0602 conditions in the first place. The expensive misdiagnosis is assuming the module is bad and ordering another one, when in reality the existing module just needs the correct calibration loaded — many independent shops have replaced perfectly good PCMs because they lacked J2534 programming capability.

Vehicle-specific patterns: 2006-2012 GM vehicles after a SPS reflash interruption commonly latch P0602 and require a recovery procedure documented in GM bulletin 09-06-04-026; the module is recoverable, not dead. 2005-2010 Ford trucks that received a junkyard PCM throw P0602 until the dealer or a locksmith runs PATS relearn and loads the VIN-matched strategy file via FDRS. 2007-2013 Chrysler/Dodge/Jeep vehicles with a SKREEM/SKIM mismatch set P0602 together with immobilizer faults after a used PCM swap, requiring wiTECH and the proper PIN. 2004-2009 Toyota and Lexus with replacement ECMs require the dealer's TIS to write the immobilizer code and 4-digit security; without it the engine starts and stalls and P0602 stays active. Estimated repair: $150 to $900.