U1900

Step 1-Step 2:

Step 3-Step 4:

PINPOINT TEST 21: DTC U1900 - CAN COMMUNICATION BUS FAULT - RECEIVE ERROR (RCM)

Normal Operation
The 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 Conditions
The 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 Causes
A 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.

Step 1-Step 2:

Step 3-Step 4:

PINPOINT TEST 22: DTC U1900 - CAN COMMUNICATION BUS FAULT - RECEIVE ERROR (OCS)

Normal Operation
The occupant classification sensor (OCS) module monitors the HS-CAN for messages from the restraints control module (RCM). If the OCS module 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 Conditions
The OCS module monitors for the following fault conditions:
- Missing message from the RCM

Possible Causes
A CAN communication bus fault - receive error can be caused by:
- damaged wiring, terminals or connectors.
- 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.