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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: 74 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.
Check the bypass valve Connector for any damage
Replace connector
Go to step 2
2.
Is there any dirt or Rust on Connector
Remove the connector
and clean it and refit it
tightly
Go to Step 3
3
Perform the bypass valve actuator test. Is the test
successful
Go to step 4
Some problem in Wiring
harness connections
4.
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.
5.
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
6.
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
10
ohms?
Go to Step 8
Replace the Bypass
valve
8
Check whether any bypass pins are backed out at
ECU Connector or bypass valve connector
Rectify the
connections
Go to Step 9
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.
1. Fuel system status
2. Engine load
3. Engine coolant temperature.
4. Long term fuel trim.
5. MAP Sensor.
6. Engine Speed.
7. Vehicle Speed.
8. Spark timing.
9. Absolute throttle position.
10. Distance Travelled after MIL ON.
11. Distance travelled since fault memory last cleared.
12. Battery voltage.
Perform the actuator test for bypass valve / Dump valve. Test result should be successful.