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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: 561 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.
Component Details:
The ignition coil is mounted on thermostat housing, to have the shortest length of high tension cable connected to
spark plugs so as to reduce the level of electromagnetic radiation from HT cables and possible interference to ECU.
The ignition coil assembly - a duel spark coil with built-in power switch with a 4 pin connector operates on
conventional principle of secondary voltage generation due to induction. The primary switching (ON/OFF) is triggered
by ECU which maintain constant dwell time, i.e. time required to energize primary coil, throughout the operating
condition.
Ignition Coils A, B & C:-
An
ignition coil
(also called a
spark coil
) is an induction coil in an automobile's ignition system which transforms the
battery's low voltage to the thousands of volts needed to create an electric spark in the spark plugs to ignite the fuel.
The wire that goes from the ignition coil to the distributor and the high voltage wires that go from the distributor to each
of the spark plugs are called spark plug wires or high tension leads.
Ignition Coil Characteristics:
Stand Alone Diagnosis:
Diagnosis
Connector details
1. ECU pin 256: (cylinder 1)
2. ECU pin 254: (cylinder 2)
3. ECU pin 255: (cylinder 4)
4. Supply voltage (12V) after Main Relay
5. Ground (through solenoid)
Use multimeter to check primary coil resistance between pin (-) and pin (+B), which should be 0.6ohms.