All 2006-2011 Mitsubishi Galant four-cylinder vehicles with California (PZEV) emissions are equipped with a Direct Ozone Reduction (DOR) radiator with a tamper-proof monitor. DTC P1580 is set if the PCM does not receive the proper signal from the monitor to confirm a DOR radiator is installed in the vehicle.
On rare occasions, an unknown random occurrence momentarily interrupts the communication between the PCM and the tamper-proof monitor. This condition may set a false DTC P1580 and illuminate the MIL. The MIL will not switch off and the DTC remains stored regardless of the number of drive cycles with DOR confirmation detected. If the DTC has been cleared, it has not reoccurred in customer vehicles. Lab investigations have not been able to duplicate this anomaly. No defect exists with this condition.
Note that this does not apply only to vehicles originally sold in California. Other states may require California emissions on vehicles sold in those states starting in model year 2004.
Check the vehicle’s warranty history on the Super Screen to confirm that this is the first occurrence of DTC P1580. If so, continue with the following procedure. If DTC P1580 has been reported before, replace the radiator/sensor assembly.
1. Do NOT erase any DTCs in PCM memory until step 4 of this procedure.
2. Confirm that a DOR radiator is installed in the vehicle. Check for the following part numbers located on the radiator, or check for the “PremAir” label affixed to the top of the radiator tank.
3. Verify that the connector and wiring between the tamper-proof monitor and the wiring harness are in good condition.
4. Erase DTCs from the system.
If DTC P1580 resets, diagnose for DTC P1580 per Group 13A-Fuel in the service manual. If DTC P1580 does not reset, the procedure is complete.