765 / 5157
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: 761 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.
P0629-12: Fuel Pump Relay Control Circuit High – Circuit Short to Battery
Overview:
ISO Code
P0629-12
Customer Symptom
Engine stalls and does not start
Fault Effects (On Vehicle)
Engine stalls and does not start
Lamp Status (If Any)
CE lamp ON after 1 drive cycle
Fault Detection Condition
This fault gets logged if the Fuel pump realy control pin of EMS ECU is Short
circuited to battery
Normal Operating Condition
Proper Wiring Harness connections between EMS ECU and Fuel Pump realy
Probable Trouble Area
Wiring harness Connections, Fuel Pump Relay
Healing Condition
Engine Running and after 1 drive cycle of Fault Rectification
Fault permanent deletion
1. Clear DTC Command form Scan tool
2. Stack Over Flow.
3.40 warm up cycles.
4.ECU flashing
5. ECU Power-Fail
Component Details:
Fuel Pump is driven by a DC motor. EMS ecu controls the DC Motor supply voltage through Fuel Pump Relay to
control the Fuel Flow / Pressure. EMS ecu energizes the Fuel Pump relay coil to provide power supply to the DC
motor which drives the Fuel Pump.
Preliminary Checks:
1) Loose/ Damaged Connections between Fuel pump Relay and EMS ECU.
2) Loose/ Damaged Connections between Fuel pump Relay and Battery supply or Ground.
3) Check for back out of pins at ECU connector.
4) Check for damage of pins at ECU connector.
5) Check the continuity from Relay to the ECU pin and From battery/Ground to Relay.