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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: 819 of 1203
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.
Trouble Shooting:-
Step Checks
IF YES
IF NO
1.
Are Relay Contacts weld / Stuck Open
Replace the Relay
Go to Step 2
2.
Is there wiring harness electrical continuity between
ECUpin 131&AC relay pin X. Also Check continuity
between the Main Relay supply and the AC relay pin X.
Also check continuity from AC Relay pin X to GND.
Go to Step 3
Establish continuity
by rectifying
harness
connections as per
the circuit
schematic
3. Are there any pins damaged at EMS ECU Connector
Replace the
connector or wiring
harness
Go to step 4
4
Are there any pins backed out from the EMS ECU
Connector
Rectify/Replace
Connectors
Go to Step 5
5
Is relay getting Supply at its pin
Go to Step 6
Repair the harness
as per the
schematic
6
Is AC Relay control Pin 131, Short circuited to GND
Repair the harness
as per the schematic Go to Step 7
7
Is AC Compressor Working or stalled
Rectify / Replace AC
Compressor
Go to Step 8
8
Fault Still Persists?
Replace relay and
then if Fault still
persists then
Replace EMS ECU
Follow the steps
again 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 Actuator test of AC Relay. Test should be successful.