For 1990-2009 cars only
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. |
| • | Use a scan tool to clear DTCs. |
| • | Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to ECC System Check in Section 1 | Go to A Powertrain On Board Diagnostic (OBD) System Check |
