NEXON DIAGNOSTIC MANUAL

Nexon Gasoline – EMS ECU Bosch

DTC Troubleshooting Manual

Version: 0.1

Date: 26-08-2017

Prepared By: Sunu S Babu/Yogesh Jadhav

Checked By: Yeshwant Jadhav

Approved By: Satish Kumar

Document Part No: 2921 02 224 A1736

Page: 113 of 1203

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.

Trouble Shooting:-

Step Checks

IF YES

IF NO

Check the bypass valve Connector for any damage

Replace connector

Go to step 2

Is there any dirt or Rust on Connector

Remove the

connector and clean

it and refit it tightly

Go to Step 3

Perform the bypass valve actuator test. Is the test

successful

Go to step 4

Some problem in

Wiring harness

connections

Check the continuity between the EMS ECU pin 149 and

connector pin 2. Check the continuity between the bypass

valve connector pin 1 and EMS main relay supply. Is

continuity test successful

Go to step 5

Establish continuity

by rectifying wiring

harness

connections as per

the schematic.

Is the bypass connector pin 1 short Circuited to

battery/Ground? Perform this test by keeping Ignition Off.

Go to Step 6

Rectify Wiring

Harness

connections as per

the schematic

Check whether the bypass valve control pin 149 is Short

Circuited to battery/Ground or Open Circuited

Rectify Wiring

Harness

connections as per

the schematic

Go to step 7

7. Is the resistance across the bypass valve terminals less

than

ohms?

Go to Step 8

Replace the

Bypass valve

Check whether any bypass pins are backed out at ECU

Connector or bypass valve connector

Rectify the

connections

Go to Step 9

Is there any physical damage to bypass valve connector /

ECU Connector

Replace the

respective

connectors

Go to step 10

10 If the fault still persists

Replace the EMS

ECU

Repeat the above

procedure for

reconfirmation

DTC’s confirmation:-

After rectification, ensure the following points by referring engine parameters using TML diagnostic tool before

handing over to customer.

Perform the actuator test for bypass valve / Dump valve. Test result should be successful.