Hyundai Elantra (CN7): Charging System / Alternator

Hyundai Elantra (CN7) 2021-2025 Service Manual / Engine Electrical System / Charging System / Alternator

Description and operation

Description

The Alternator has eight built-in diodes, each rectifying AC current to DC current.

Therefore, DC current appears at alternator "B" terminal.

In addition, the charging voltage of this alternator is regulated by the battery voltage detection system.

The alternator is regulated by the battery voltage detection system.

The main components of the alternator are the rotor, stator, rectifier, capacitor brushes, bearings and V-ribbed belt pulley.

The brush holder contains a built-in electronic voltage regulator.

1. Brush
2. Drive belt pully
3. Stator
4. Rotor

Specifications

Specification

Item		Specification
Rated voltage		13.5V, 130A
Speed in use		1,000 - 18,000 rpm
Voltage regulator		IC Regulator built-in type
Regulator Setting Voltage	External mode	10.6 - 16 ± 0.3V
	Internal mode	14.55 ± 0.3V
Temperature Gradient	External mode	0 ± 2 mV / °C
	Internal mode	-3.5 ± 2mV / °C

Schematic diagrams

Circuit Diagram

•	COM signal - When controlling the voltage generated, the ECM sends the target voltage data to the alternator via a PWM signal. (High Voltage : 4V, Low Voltage : 2V)

•

FR signal - The transistor activation signal inside the alternator monitors the voltage generated by the alternator to control the excitation current before it sends the FR signal to the ECM. (At certain RPM/electric loads, the FR duty can remain static. However, more often, the RPM, electric load, target voltage, etc. are always changing in the vehicle, so the FR must also change constantly)

•	L signal - Turns on the battery warning lamp on the dashboard when the battery charging system malfunctions. (Conditions for turning on the lamp - overcharge, over discharge, a field coil blown inside the alternator)

•	B+ terminal - The output voltage from the generator travels to the battery via the B+ terminal.

Repair procedures

Removal

1.	Turn ignition switch OFF and disconnect the negative (-) battery cable.

2.	Remove the drive belt tensioner. (Refer to Engine Mechanical System - "Drive Belt Tensioner")

3.	Remove the drive belt. (Refer to Engine Mechanical System - "Drive Belt")

Remove return hose & pipe braket bolt (A).

Tightening torque : 9.8 - 11.8 N.m (1.0 - 1.2 kgf.m, 7.2 - 8.7 lb-ft)

Disconnect the cable (C) from alternator "B" terminal after disconnect the compressor connector (A) and the alternator connector (B).

Tightening torque : 9.8 - 11.8 N.m (1.0 - 1.2 kgf.m, 7.2 - 8.7 lb-ft)

Remove the alternator (B) after loosening the mounting nuts (A).

Tightening torque : 40.03 - 63.7 N.m (5.0 - 6.5 kgf.m, 36.1 - 47.0 lb-ft)

Installation

1.	Install in the reverse order of removal.

Disassembly

1.	Remove the rear cover (A).

Remove the mounting bolts and the regulator assembly (A).

•	When removing take care not to damage the surrounding parts.

Remove the OAP cap (A).

•	When installing, replace with new OAP cap.

4.	Remove the OAP pulley (A) by using the SST (09373-27000).

5.	Remove the rectifier assembly (A) after disconnecting the stator leads.

6.	Remove the through bolts (A).

7.	Disconnect the rotor (A) and housing (B).

Reassembly

1.	Reassemble in the reverse order of disassembly.

Inspection

[Rotor]

1.	Check that there is continuity between the slip rings (C).

2.	Check that there is no continuity between the slip ring (C) and the rotor (B) or rotor shaft (A).

3.	If the rotor fails either continuity check, replace the alternator.

[Stator]

1.	Check that there is continuity between each pair of leads (A).

2.	Check that there is no continuity between each lead and the coil core.

3.	If the coil fails either continuity check, replace the alternator.

❮Repair procedures

InspectionInspecion Item• Battery efficiency inspection• Battery voltage inspection• Charging voltage insptection• General inspection• Terminal tightening state inspection• Engine/ transaxle ground state inspection• Wiring hareness ground state inspection• Electrical Specified Value Inspection• Vehicle parasitic current inspection • Inspect the battery capacityBattery Efficiency Inspection • Check that the battery cables are connected to the correct terminals.

Battery❯

Description and operation Description1.The CMF (Closed Maintenance Free) battery is, as the name implies, totally maintenance free and has no removable battery cell caps.

Other information:

Hyundai Elantra (CN7) 2021-2025 Service Manual: Components and components location

Hyundai Elantra (CN7) 2021-2025 Service Manual: Blower Resistor (Manual)

Repair procedures Inspection1.Measure the resistance between the terminals.2.The measured resistance is not within specification, the blower resistor must be replaced. (After removing the resistor)Replacement1.Disconnect the negative (-) battery terminal.