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

Prepared by: Airbag COC Review Approved by: Sanjeev VM Page: 524 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 U0028-13:- Vehicle Communication Bus A - circuit open ISO Code U0028-13 Customer Symptom SRS Warning Lamp continuously ON in Instrument Cluster. Fault Effects (On Vehicle) 1. SRS (Airbag) Warning lamp functionality will be affected. 2. SBR Chime functionality will be affected. 3. Door unlock & hazard light functionality will be affected. Lamp Status (If Any) SRS Warning Lamp continuously ON in Instrument Cluster. Fault Detection Condition 1. Open circuit of the CAN_H (pin A12), CAN_L (pin A11) and/or both lines 2. Short circuit of CAN_H (pin A12) – Battery and/or CAN_L (pin A11) - Ground Normal Operating Condition SRS ECU should communicate properly with other ECU’s in vehicle. Probable Trouble Area CAN_H and CAN_L wires (Wiring harness), ECU connectors, ECU pins. Healing Condition 1. Re-connection of the CAN_H (Pin A12) and CAN_L (Pin A11) to RCM ECU. 2. Removal of the above short circuits. Airbag Warning Lamp behaviour for U0028-13 DTC:- U0028-13 IVN DTC is healed in the same IGN cycle; once corresponding failure detection conditions are not present. However, Airbag Warning Lamp (triggered due to this failure/DTC) will turn off in following two conditions. a. When above mentioned DTC is in healed state and Clear DTC command is sent; in this case Lamp will be OFF in same IGN cycle b. When above mentioned DTC is in healed state and IGN OFF/ON (1 time) operation is done. This is implemented as per supplier’s strategy. 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. Ensure the proper locking of Airbag ECU wiring harness connectors in the vehicle by the locking sound. 2. Check resistance between diagnostic CAN pin number 6 and 14 in OBD connector. It should be 120 ohm. 3. Check for short conditions between CAN_H-CAN_L, CAN_H-GND, CAN_L-GND, CAN_H-Vbat and CAN_LVbat. There should not be any short circuit conditions. 4. Check continuity between IPC CAN_H vehicle side connector to OBD connector CAN_H and CAN_L vehicle side connector to OBD connector CAN_L 5. Read IVN DTC’s in IPC in Ignition ON condition.