TIAGO TIGOR BSVI - SERVICE MANUAL - DTC 24-12-2021

Prepared by: Airbag COC Review Approved by: Sanjeev VM Page: 504 of 648 Copyright © TATA MOTORS Ltd. This document must not be used in any way, such as copying and redistributing to third parties, without the consent of author. SRS / Airbag ECU AB12 DTC Troubleshooting Guide Version: 2.0 Date: 21-June-2021 U0121-08 Lost Communication With Anti-Lock Brake System (ABS) Control Module - Bus Signal / Message Failures ISO Code U0121-08 Customer Symptom ABS Communication is lost. DTC U0121-08 is qualified Fault Effects (On Vehicle) SBR Functionality not guaranteed. Lamp Status (If Any) SRS Warning Lamp continuously ON in Instrument Cluster. Fault Detection Condition 1. Check connector pin backout or damaged crimp for ABS ECU side 2. ABS Communication is lost. Normal Operating Condition ECU Communication is proper. DTC U0121-08 should not be present. Probable Trouble Area 1. CAN_H and CAN_L wires (Wiring harness), Tx ECU connectors, Tx ECU pins. 2. ABS ECU message transmission. Healing Condition 1. Fix the Wiring harness at the sender 2. Check the communication from sender ECU. Component Details:- (Refer Annexure 2 for Mounting Location of AB12 Airbag ECU) Airbag ECU : - It is fitted in the floor of central console in the car. The Airbag Electronic Control Unit (ECU) controls the deployment system to allow an appropriate igniting of the Airbags and belt pre-tensioners to restrain the driver and passengers. Preliminary Checks:- 1. Check Battery Voltage (12 V & above) 2. Check for any faults in Airbag Warning Lamp indication in Instrument Cluster. 3. Ensure the proper locking of Airbag ECU wiring harness connectors in the vehicle by the locking sound. Troubleshooting:-