HARRIER BOOK 2

TATA MOTORS Ltd.

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SRS / Airbag

ECU – DTC Troubleshooting Guide

Version: 14.0

Date: 14-February-2017

Prepared by:Airbag COC Review &

Approved by:Sanjeev VM

Page: 371 of 549

U0401-81:- Invalid Data Received FromECM/PCM "A" - Invalid serial data received

Overview:-

ISO Code

U0401-81

Customer Symptom

N.A.

Fault Effects (On Vehicle)

No effect.

Lamp Status (If Any)

N.A.

Fault Detection Condition

Incorrect or implausible vehicle speed data received from

ECM control module by RCM (SRS) ECU.

Normal Operating Condition

Error free communication between RCM and ECM Control

Module.

Probable Trouble Area

Implausible vehicle speed data received from ECM ECU.

Healing Condition

Clearing of the functional failures in the ECM Module.

Component Details:-

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 ECM CAN_H (pin no. 19) vehicle side connector to OBD connector CAN_H (pin no.

6) and CAN_L (pin no. 18) vehicle side connector to OBD connector CAN_L (pin no.14).

5. Read IVN DTCs in IPC in Ignition ON condition.