This diagnostic test checks for the loss of or invalid Instrument Panel Cluster (IPC) serial data to the PCM. When such a condition exists for 11 seconds, DTC P1604 is set.
| • | DTC P0322 not set. | 
| • | Engine speed 500 RPM or more for 10 seconds continuously. | 
Invalid or no serial data from the IPC to the PCM for 11 seconds.
| • | The Malfunction Indicator Lamp (MIL) will not illuminate. | 
| • | No message will be displayed. | 
| • | 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 Powertrain Control Module Description . | 
Step  | Action  | Value(s)  | Yes  | No  | 
|---|---|---|---|---|
1  | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?  | --  | Go to Step 2  | |
2  | The IPC is not communicating with the PCM. Refer to PCM Replacement in order to diagnose the Serial Data circuit and the IPC.  | --  | --  | --  |