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Mechanic’s Education Association

www.MEAtraining.com Instructor: Al Dambrauskas

RVC Regulated Voltage ControlRegulates Alt Output Based On Battery State of

Charge and Estimated Battery Temperature

Extends Battery Life and Improves Fuel Mileage

2004 and Newer Trucks and Cars

Generator Battery Control Module (GBCM)

Body Control Module (BCM)

Engine Control Module (ECM)

Dash Integration Module (DIM)

Instrument Panel Module (IPM)

Instrument Panel Cluster (IPC)

Battery Current Sensor

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9 Modes Of Operation

• Charge Mode

• Fuel Economy Mode

• Voltage Reduction Mode

• Start Up Mode

• Headlamp Mode

• Battery Sulfation Protection Mode

• Windshield Wiper Voltage Boost Mode

• Fuel Pump Voltage Boost Mode

• De – Ice Voltage Boost Mode

Battery Must Be Charged: System May Not Turn On Alternator If Voltage Is Too Low

• Charge Mode: – Battery SOC Is Less Than

80%– Cooling Fans On High

Speed– Rear Defogger On– Current Sensor NOT

Between – 8 to 15 amps– Outside Air Temp Is Less

Than 0 Celsius

9 Modes Of Operation

• Fuel Economy Mode: – Battery SOC Is More Than 80%– Cooling Fans On Low Speed Or

Off– Rear Defogger Off– Current Sensor Is Between Or Less

Than – 8 to 15 amps– Outside Air Temp Is More Than 0

Celsius

In this mode: alternator output will be ramped up to 13.4v – 15.5v at a rate of 20 milli-volts per second

In this mode: when all

criteria is met, the target

voltage will be 13.0 volts

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• Voltage Reduction Mode: – Battery SOC Is More Than 80%– Cooling Fans On Low Speed Or Off– Rear Defogger Off– Current Sensor Is Between Or Less

Than – 7 to 2 amps– Outside Air Temp Is More Than 0

Celsius

9 Modes Of Operation

In this mode:

Voltage can Reduced To 12.9 Volts

12.9V

• Start Up Mode: – Voltage Target Is 14.5

Volts for 30 Seconds

14.5V

• Battery Sulfation Mode: – Alternator Output Has Been

13.2 volts For More Than 45 Minutes

– Will Enter Charge Mode For 3 Minutes To See If Battery Voltage Comes Up

9 Modes Of Operation

13.2V

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9 Modes Of Operation

• Headlamp Mode

• Windshield Wiper Voltage Boost Mode

• Fuel Pump Voltage Boost Mode

• De – Ice Voltage Boost Mode

Voltage Is Increased When Any Of These

Accessories Are Turned On To Maintain SOC

RVC: Regulated Voltage Control

2 Types Of RVC Systems and

Stand Alone RVC: Integrated RVC:

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SARVC: Stand Alone Regulated Voltage Control

Alternator With New Style Regulator

Battery Control Module With Internal Current Sensor

PCM Communicate With Battery Control Module By

Class 2 Data

Instrument Panel Cluster Communicates Over Class 2 To Notify Driver Of Charging

System Malfunctions Mounted On Negative Battery Cable Near

Battery

2007 GMC Sierra P/U SARVC

Stand Alone Regulated Voltage Control

Used On Trucks

L Terminal Charge Indicator

Control

F Terminal Generator Field

Duty Cycle Signal

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2007 GMC Sierra 3500 P/U 6.0L SARVC

Generator Battery Control Module

ALT IPC

Terminal F

Terminal L

Current Sensor Internal

Power Feeds

Grounds

Class 2 Communication

Engine On Signal

Pin B: Grey Wire

F TerminalPin D: Brown

WireL Terminal

Generator Battery Control Module Pins

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SARVC: Stand Alone Regulated Voltage Control (Under Load)

L Terminal @ 128Hz: Voltage Aprox. 2.60 Volts ( 0 – 4 volts )

F Terminal @ 400Hz: Voltage Aprox. 6.94 Volts ( 0 – 9 volt )

L Terminal Voltage

Varies From Aprox, 2 – 4

volts

F Terminal Voltage

Varies From Aprox, 3 – 8

volts

Pin G: Engine On Signal (Dark Blue Wire)

Generator Battery Control Module Engine On Signal

.5 volts Key On

13.78 volts Running

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RVC: Regulated Voltage Control

Works With 2 Wire To Alternator L and F

128 Hz Signal Is Sent To Alt on L Terminal: 0 To 5 volt

Square Wave

Duty Cycle Control on L Terminal Sets Regulator In

Alternator

F Terminal Is Feedback From Alternator (@ 400Hz)

Orange: Generator Turn On Signal: .148 volts

KOEO, 3.97 volts Running Open Circuit

Grey: Generator Field Duty Cycle Signal:

.007 volts KOEO.047 volts Running Open

Circuit

Orange: Generator Turn On Signal (L) 3.67 volts Varying

Grey: Generator Field Duty Cycle (F) 6.08 volts Varying

Alternator At Idle

If “L” Terminal Is Open or Grounded, Alternator Will Default To 13.8 volt Output

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Command On “L” Terminal To Change Regulator Set Point

If Command Is Less Than 10% or Higher Than 90% Alternator Defaults To Internally Regulated

At 13.8 volts

Normal Range

Scan Data

L Terminal Command

F Terminal Load Feedback

60% Command Would Result In Alternator Outputting 13.81 volts

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Alternator No Load

L Terminal 0 – 5 volt Square Wave

F Terminal 0 – 7 volt Square Wave

Alternator Heavy Load

Limitation Using Scope

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Scan DataEPM Data

SOC 88%

Desired Voltage

Voltage

2008 Impala 5.3L V8 RVC

Current Sensor Terminal L

Terminal FBody Control Module

ECM

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2008 Impala 5.3L v8

Battery Current SensorOpen Circuit KOEO

Pink: (Reference Voltage) 5.10 volts

Brown: (Signal Ground) .081 volts

White: (Signal) 5.09 volts

Battery Current Sensor

White: Signal 3.5 volts, Frequency 120Hz, Duty

Cycle 32%

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Battery Current Sensor

0 – 5 volt Square Wave

Functional Tests

Generator L-Terminal

Control

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Functional Tests

Generator L-Terminal

Control

L-Terminal Normal Operation

5 Volt Square Wave @ Aprox.

75% Duty Cycle

Command From PCMVoltage On

Meter Will Be Aprox. 14.5

volts

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Functional Tests Generator L Terminal Command On To 85%

L Terminal @ 85% Duty

CycleVoltage On Meter Goes

To Aprox. 15 volts

Functional Tests Generator L Terminal Command On To 15%

L Terminal @ 15% Duty

CycleVoltage On Meter Goes

To Aprox. 12 volts

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Battery Saver MessageBattery Voltage High:

System Voltage Is Greater Than 16 Volts

Battery Voltage Low:

System Voltage Is Less Than 11 Volts

Battery Saver Active:

One or More System Is Altered To Reduce Load On Charging System

Idle Boost

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Load Shedding

BCM Monitors Battery For Excessive Loads

BCM Strategy Is To Lower Loads To Save

Battery

Can Be Monitored On Scan Tool

Loads Subject To Periodic Deactivations

Air Conditioning Clutch

Heated Mirrors

Heated Seats

Rear Window Defogger

HVAC Blower

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Load Shed Level

Affected Systems Action Taken

Load Shed

Level 0

No System Affected

Normal Operation

Load Shed

Level 1

Load Shed

Level 2

Load Shed

Level 3

Load Shedding

Message Center

Message Center

Message Center

Heated Rear View Mirrors Cycled at 80% Duty Cycle, Off for 4 of every 20 second cycle

No Messages or Indicators Displayed

Heated Rear View Mirrors, Rear Defrost,

Heated Seats

Heated Rear View Mirrors, Rear Defrost,

Heated Seats

Cycled at 50% Duty Cycle, Off for 10 of every 20 second cycle

“Battery Saver Action” Message Displayed, or Flashing Indicator

Turned Off

“Battery Saver Action” Message Displayed, Battery charging system Indicator on

2003 Chevrolet Impala 3.4LOver Heats

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Isolate Splice Pack 205

Find The Splice Pack SP205

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Disconnect Body Module

Communication Wire

Splice Pack 205

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