P1605

CIRCUIT DESCRIPTION

This diagnostic test checks for the loss of or invalid Heater and A/C (HVAC) programmer serial data to the PCM. When such a condition exists for 11 seconds, DTC P1605 is set.

CONDITIONS FOR SETTING THE DTC

Test Conditions

^ DTC P0322 not set.
^ Engine speed 500 RPM or more for 10 seconds continuously.

Failure Condition

Invalid or no serial data from the HVAC programmer to the PCM for 11 seconds.

ACTION TAKEN WHEN THE DTC SETS

^ The Malfunction Indicator Lamp (MIL) will not illuminate.
^ No message will be displayed.

CONDITIONS FOR CLEARING THE DTC

^ A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test.
^ A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.
^ PCM battery voltage is interrupted.
^ Using a Scan tool.