Dodge Ram 2004 - Engine Gauge Rx Failure (Active)

Symptom List:
ENGINE GAUGE RX FAILURE (ACTIVE)
PCM COMMUNICATION FAILURE (ACTIVE)
REFRIGERANT PRESSURE RX FAILURE (ACTIVE)
VIN RX FAILURE (ACTIVE)
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be ENGINE GAUGE RX FAILURE
(ACTIVE).
When Monitored and Set Condition:
ENGINE GAUGE RX FAILURE (ACTIVE)
When Monitored: With the ignition on.
Set Condition: This DTC will set if the A/C - Heater Control Module does not receive the
message from the PCM for more than 5 seconds. This message provides Battery Voltage,
Battery Temperature, and Engine Coolant Temperature.
PCM COMMUNICATION FAILURE (ACTIVE)
When Monitored: With the ignition on.
Set Condition: This DTC will set if the A/C - Heater Control Module does not receive the
message from the PCM for more than 5 seconds. This message provides Engine RPM and
Vehicle Speed.
REFRIGERANT PRESSURE RX FAILURE (ACTIVE)
When Monitored: With the ignition on.
Set Condition: This DTC will set if the A/C - Heater Control Module does not receive the
Refrigerant Pressure message from the PCM for more than 20 seconds.
VIN RX FAILURE (ACTIVE)
When Monitored: With the ignition on.
Set Condition: This DTC will set if the A/C - Heater Control Module does not receive the
VIN message from the PCM for more than 5 seconds.
POSSIBLE CAUSES
CHECK FOR ADDITIONAL HVAC DTCS
CHECK FOR PCM DTCS
A/C - HEATER CONTROL MODULE
PCM - NO MESSAGE TO A/C - HEATER CONTROL MODULE
388
HEATING & A/C