OBD-II Code · Computer
P0602
Control Module Programming Error
Severity
high
Left alone, this one tends to take other parts with it.
Can you drive it
Not for long
Driving on this one risks further damage. Get it to a shop rather than carrying on with it.
Indicative cost (USD)
$150–$1,500
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
PCM not programmed or corrupted.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- No start
- Check engine light
Likely causes
- Incomplete reflashMost common
- Failed PCM
Read the full diagnostic procedureP0602 is set when the PCM detects that it has not been programmed, has been programmed incorrectly, or is missing the VIN, calibration, or variant co…
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 patterns2006-2012 GM vehicles after a SPS reflash interruption commonly latch P0602 and require a recovery procedure documented in GM bulletin 09-06-04-026;…
- 2006-2012GM 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.
- 2005-2010Ford 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.
- 2007-2013Chrysler/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.
- 2004-2009Toyota 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.
Look up another code
P0602 — frequently asked
What does a P0602 code mean?
PCM not programmed or corrupted.
What causes a P0602 code?
Common causes: Incomplete reflash; Failed PCM.
What are the symptoms of a P0602 code?
Typical symptoms: No start; Check engine light.
Is it safe to drive with a P0602 code?
Not for long. Driving on this one risks further damage. Get it to a shop rather than carrying on with it. Estimated repair: $150-$1,500.
How do I diagnose a P0602 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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