U0028:88
PINPOINT TEST 30: DTCs U0028:08 AND U0028:88
Normal Operation
The Restraints Control Module (RCM) supplies the stability/traction control system with the yaw rate, roll rate, lateral and longitudinal accelerometer over a dedicated Controller Area Network 2 (CAN2) bus. If the RCM detects a fault with communications with the ABS module or CAN2 bus circuits, it will store DTC U0028:08 or DTC U0028:88 in memory.The RCM will not request the Instrument Cluster (IC) module to illuminate the air bag warning indicator if either DTC U0028:08 or DTC U0028:88 is set. The air bag warning indicator will remain off if either of these DTCs are set.
- DTC U0028:08 (Vehicle Communication Bus A: Bus Signal / Message Failures) - When the RCM does not receive CAN2 bus messages from the ABS module for 5 seconds, a fault will be indicated. An open CAN2 circuit, incorrect installed ABS module or loss of power and/or ground to the ABS module can set this DTC.
- DTC U0028:88 (Vehicle Communication Bus A: Bus Off) - When the RCM detects the CAN2 circuits are shorted to ground, shorted to voltage or shorted to each other, a fault will be indicated.The ABS module may set DTCs U0151 (Lost Communication With Restraints Control Module) and U0452 (Invalid Data Received From Restraints Control Module).
Possible Causes
- Wiring, terminals or connectors
- RCM
- ABS module
Diagnostic Procedure
WARNING:Do not handle, move or change the original horizontal mounting position of the restraints control module (RCM) while the RCM is connected and the ignition switch is ON. Failure to follow this instruction may result in the accidental deployment of the safety canopy and cause serious personal injury or death.
WARNING:Never probe the electrical connectors on air bag, safety canopy or side air curtain modules. Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.
WARNING:Never probe the electrical connectors on safety belt buckle/retractor pretensioners or adaptive load limiting retractors. Failure to follow this instruction may result in the accidental deployment of the safety belt pretensioners or adaptive load limiting retractors, which increases the risk of serious personal injury or death.
CAUTION:Use the correct probe adapter(s) from the Flex Probe Kit when taking measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE:Supplemental Restraint System (SRS) components should only be disconnected or reconnected when instructed to do so within a pinpoint test step. Failure to follow this instruction may result in incorrect diagnosis of the SRS.
NOTE:The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
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