Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
The cost to diagnose the B1891 code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.
The connection between the Instrument Cluster Module and Restraints Control Module (RCM) is used to signal a chime if the primary air bag indicator is inoperative and another Supplemental Restraint System (SRS) fault exists. The RCM monitors this connection to the Instrument Cluster Module. If the RCM detects a circuit failure on the connection to the cluster, it will store diagnostic trouble code (DTC) B1891 in memory and flash lamp on the air bag indicator.
B1891 Code - Air Bag Tone Warning Indicator Circuit Short to Battery
Precautions for SRS “AIR BAG” and “SEAT BELT PRE-TENSIONER” Service
Never probe the electrical connectors on air bag, side air curtain modules or seat belts.
Never disassemble or tamper with safety belt buckle/retractor pretensioners, adaptive load limiting retractors, safety belt inflators, or probe the electrical connectors.
Do not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 minutes. For approximately 3 minutes after the cables are removed,
it is still possible for the air bag and seat belt pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes have passed.
Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.