Pinpoint Test 21: DTC U1900 - Can Communication Bus Fault - Receive Error (RCM)
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PINPOINT TEST 21: DTC U1900 - CAN COMMUNICATION BUS FAULT - RECEIVE ERROR (RCM)
Normal OperationThe restraints control module (RCM) monitors the HS-CAN for messages from the instrument cluster module, occupant classification sensor (OCS) module and the powertrain control module (PCM). If the RCM detects a communication bus fault or missing messages, it will store diagnostic trouble code (DTC) U1900 in memory and illuminate the air bag indicator.
Fault ConditionsThe RCM monitors for the following fault conditions:
- Missing message from the instrument cluster module
- Missing message from the PCM
- Missing message from the OCS module
Possible CausesA CAN communication bus fault - receive error can be caused by:
- damaged wiring, terminals or connectors.
- a faulted instrument cluster module.
- a faulted PCM.
- a faulted OCS module.
- a faulted RCM.
NOTE:Most faults are due to connector and/or wiring concerns. Carry out a thorough Inspection and Verification before proceeding with the pinpoint test.
