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Contents Wiring diagrams Section: Charging System All sections

Battery, Charging System and Starting System (Except Hybrid) Buick LaCrosse II

Charging System 10 illustrations ~13963 words

Fastener Tightening Specifications

ApplicationSpecification
MetricEnglish
Accessory DC Power Control Module Fastener22 N.m16 lb ft
Accessory Wiring Junction Block Fastener10 N.m89 lb in
Battery Hold Down Retainer Fastener10 N.m89 lb in
Battery Hold Down Strap Fastener12 N.m106 lb in
Battery Negative Cable Fastener (Battery Post)4.5 N.m40 lb in
Battery Negative Cable Ground Fastener (Engine Block)25 N.m18 lb ft
Battery Negative Cable Ground Fastener (Frame Rail)12 N.m106 lb in
Battery Positive Cable to Engine Wiring Junction Block Fastener17 N.m9 lb ft
Battery Positive Cable Fastener (Battery Post)4.5 N.m40 lb in
Battery Positive Cable Fastener (Battery Fuse Block)12 N.m106 lb in
Battery Positive Cable Fastener at the Starter (V6)25 N.m18 lb ft
Battery Tray Fastener20 N.m15 lb ft
Body Harness Negative Ground Fastener (Battery Post)9 N.m80 lb in
Engine Ground Strap to Engine Block Fastener22 N.m16 lb ft
Engine Ground Strap to Wheelhouse Panel Fastener22 N.m16 lb ft
Engine Control Module Wiring Harness Ground Cable to Cylinder Head Fastener12 N.m106 lb in
Engine Control Module Wiring Harness Ground Cable to Transmission Fastener9 N.m80 lb in
Generator BAT Terminal Fastener20 N.m15 lb ft
Generator Bracket Fastener58 N.m43 lb ft
Generator Fastener (V6)50 N.m37 lb ft
Starter Motor Mounting Fastener53 N.m39 lb ft
Starter Shield Fastener7 N.m62 lb in
Starter Solenoid Fastener10 N.m89 lb in

Fastener Tightening Specifications

Battery Usage

ApplicationSpecification
Cold Cranking Amperage (CCA)615 A
Amp Hour Rating70 Ah

Battery Usage

Generator Usage

ApplicationSpecification
2.4L (LAF)
Generator ModelTG13 (Valeo)
Rated Output125 A
Load Test Output87 A
3.0L (LF1) or 3.6L (LLT)
Generator ModelSC2 (Denso)
Rated Output155 A
Load Test Output108 A

Generator Usage

Scheme 1

Scheme 1: Starting
Scheme 1: Starting

Scheme 2

Scheme 2: Charging
Scheme 2: Charging

Diagnostic Code Index

DTCDescription
DTC B1325, B1330, B1517, C0800, P0560, P0562, or P0563DTC B1325 03 Device Power Circuit Voltage Below Threshold DTC B1325 07 Device Power Circuit Voltage Above Threshold DTC B1330 03 Device Power 2 Circuit Voltage Below Threshold DTC B1517 03 Battery Voltage Below Threshold DTC B1517 07 Battery Voltage Above Threshold DTC B1517 5A Battery Voltage Plausibility Failure DTC C0800 03 Device Power 1 Circuit Voltage Below Threshold DTC C0800 07 Device Power 1 Circuit Voltage Above Threshold DTC C0800 11 Device Power 1 Circuit High Input DTC C0800 0D Device Power 1 Circuit High Resistance DTC P0560 System Voltage Low DTC P0562 System Voltage Low DTC P0563 System Voltage High
DTC B1516DTC B1516 08 Battery Current Sensor Signal Invalid DTC B1516 66 Battery Current Sensor Wrong Mounting Position
DTC B151ADTC B151A 58 Low Battery Capacity Detected
DTC B1527DTC B1527 00 High Parasitic Load Detected
DTC P0615, P0616, or P0617DTC P0615 Starter Relay Control Circuit DTC P0616 Starter Relay Control Circuit Low Voltage DTC P0617 Starter Relay Control Circuit High Voltage
DTC P0621DTC P0621 Generator L-Terminal Circuit
DTC P0622DTC P0622 Generator F-Terminal Circuit
DTC P0625 or P0626DTC P0625 Generator F-Terminal Circuit Low Voltage DTC P0626 Generator F-Terminal Circuit High Voltage

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit/System Description

The vehicle control modules or sensors monitor the system voltage to verify the system voltage is within the normal operating range.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The control module or sensor detects a system voltage of less than approximately 9 V or greater than 18 V for approximately 5 seconds.

Action Taken When the DTC Sets

  1. A driver information center message and/or warning indicator may be displayed.
  2. The control module may be temporarily disabled.

Conditions for Clearing the DTC

The system voltage returns to normal operating range.

Diagnostic Aids

  1. A high or low voltage DTC set or voltage value in multiple modules/sensors indicates a concern in the charging system.
  2. A possible cause of this DTC could be overcharging with a battery charger or jump starting.

Reference Information

Schematic Reference

Connector End View Reference

  1. «COMPONENT CONNECTOR END VIEWS - INDEX»(/buick/lacrosse/ii-2009-2013/remont/body-electrical/#wiring-systems-and-power-management-component-connector-end-views-index)
  2. «Inline Harness Connector End Views»(/buick/lacrosse/ii-2009-2013/remont/body-electrical/#wiring-systems-and-power-management-inline-harness-connector-end-views)

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. DT 47825-10 Adapter Harness
  2. DT 47825-20 Adapter Harness
  3. DT 48616-10 Adapter Harness

For equivalent regional tools, refer to Special Tools .

Circuit/System Verification

  1. Ignition OFF, measure and record the battery voltage at the battery terminals. The battery voltage should stabilize between 12.4 and 12.8 V within a few minutes of turning the ignition OFF. If not within the specified range, refer to «Battery Inspection/Test»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  2. Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be at least 1 V greater than the voltage measured in step 1 but less than 15 V. If not within the specified range, refer to «Charging System Test»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  3. Observe the appropriate module scan tool B+ and ignition voltage parameters. The voltage readings should be within 1 V of the battery voltage.

Circuit/System Testing

Note. Use the schematic to identify the following: Control modules the vehicle is equipped with The control modules ground, B+, and ignition circuit terminal IDs and connectors

  1. Ignition OFF, disconnect the harness connectors at the appropriate control module.
  2. For the transmission control module only, connect the appropriate adapter harness to the transmission connector.
  3. Ignition OFF, scan tool disconnected, open and close the driver door and wait 1 minute. Test for less than 10 ohms between each ground circuit terminal and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. If equipped, test for greater than 9 V between each B+ circuit terminal and ground. If less than the specified range, test the B+ circuit for a short to ground or an open/high resistance.
  5. If equipped, ignition ON, test for greater than 9 V between each ignition circuit terminal and ground. If less than the specified range, test the ignition circuit for a short to ground or an open/high resistance.
  6. If all circuits test normal, replace the appropriate control module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for control module replacement, programming and setup

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V ReferenceB1516 08B1516 08
SignalB1516 08B1516 08B1516 08B1516 08, B1516 66
Low ReferenceB1516 08

The battery current sensor is a 3-wire hall effect current sensor. The body control module (BCM) supplies 5 V and ground to the battery current sensor. The battery current sensor measures the amount of current flowing to or from the battery, and supplies a pulse width modulation (PWM) signal to the BCM.

B1516 08

The BCM is awake.

B1516 66

  1. The BCM is awake.
  2. The engine is OFF.

B1516 08

The battery current signal is less than 4 percent or greater than 96 percent duty cycle for 2 minutes.

B1516 66

The battery current polarity is positive for 2 minutes.

The regulated voltage control (RVC) is disabled.

The DTC passes when the battery current returns to the normal range for 15 seconds.

DTC B1516 08 could be set by overcharging with a battery charger or jump starting.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

B1516 08

  1. Ignition OFF, disconnect the harness connector at the B18 battery current sensor.
  2. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 30 ohms between the low reference circuit terminal B and ground. If greater than specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K9 BCM.
  3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal A and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
  4. Ignition ON, test for 4.8-5.2 V between the signal circuit terminal C and ground. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
  5. If all circuits test normal, test or replace the B18 battery current sensor.

B1516 66

  1. Verify that the B18 battery current sensor is installed securely around the negative battery cable, with the tape tab pointing away from the negative terminal on the C1 battery. If the B18 battery current sensor is not installed correctly, remove and reinstall the sensor properly.
  2. Replace the B18 battery current sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Battery Current Sensor Replacement»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The body control module (BCM) monitors the battery voltage level during an engine crank event to detect a low battery voltage condition.

The vehicle is ON

A minimum crank battery voltage is less than the minimum crank battery voltage threshold for 16 consecutive crank events.

A driver information center (DIC) message is displayed.

The DTC will clear if the minimum crank voltage is greater than the minimum crank voltage threshold during a crank event.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Before replacing the C1 battery perform the Battery Inspection/Test .

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The body control module (BCM) monitors the state of charge of the electrical system. If the BCM senses that the state of charge at ignition On is 30 percent lower than what it was when the engine was running.

The ignition must be in Accessory or Run mode for this code to set.

The state of charge at ignition ON is 30 percent lower than when the engine was running and battery drain is more than 2 A.

There is no battery telltale illuminated or DIC message displayed.

  1. The DTC will clear if the fault does not return after 50 consecutive ignition cycles.
  2. The DTC will clear when run state of charge is greater than or equal to 80 percent.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
ControlP0615*, P0616**P0615*, P0616**P0615*, P0617**
GroundP0615*, P0616**
* LAF, LF1, LUK ** LLT

When the ignition switch is placed in the START position, a discrete signal is supplied to the body control module (BCM) notifying it that the ignition is in the START position. The BCM then sends a message to the engine control module (ECM) that crank has been requested. The ECM then verifies that the clutch pedal is depressed or the transmission is in Park/Neutral. If it is, the ECM then supplies 12 V to the control circuit of the starter relay. When this occurs, battery voltage is supplied through the switch of the starter relay to the starter solenoid.

With LUK engine

  1. The ignition is in the RUN or START position.
  2. The system voltage is between 9.5-18 V.

Without LUK engine

  1. The ignition is in the START position.
  2. The system voltage is between 9.5-18 V.

The ECM detects improper voltage on the control circuit of the starter relay.

DTC P0615, P0616, and P0617 are C type DTCs.

DTC P0615, P0616, and P0617 are C type DTCs.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the KR27 starter relay.
  2. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5.0 ohms between the relay ground circuit terminal 86 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground.
  4. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
  5. Parking brake applied and the transmission is in NEUTRAL or PARK. Momentarily install a 30 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the M64 starter motor is activated. If the M64 starter motor does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the M64 starter motor.
  6. Ignition OFF, connect a test lamp between the control circuit terminal 85 and the ground circuit terminal 86.
  7. Transmission in park or neutral, command the starter relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for short to voltage. If the circuit tests normal, replace the K20 ECM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  8. If all circuits tests normal, replace the KR27 starter relay.

Component Testing

Relay Test

  1. Ignition OFF, disconnect the KR27 starter relay.
  2. Test for 60-180 ohms between terminals 85 and 86. If not within the specified range, replace the KR27 starter relay.
  3. Test for infinite resistance between the following terminals: 30 and 86 30 and 87 30 and 85 85 and 87 If not the specified value, replace the KR27 starter relay.
  4. Install a 20 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than specified range, replace the KR27 starter relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Within an Electrical Center)»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions__relay-replacement-within-an-electrical-center) , «Relay Replacement (Attached to Wire Harness)»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
B+P0622P0621
ControlP0621P0621P0621
SignalP0622P0622P0622P0622

The engine control module (ECM) uses the G13 Generator turn ON control circuit to control the load of the G13 Generator on the engine. A high side driver in the ECM applies a voltage to the voltage regulator. This controls the voltage regulator to turn the field circuit ON and OFF. The ECM monitors the state of the G13 Generator turn ON control circuit. The ECM should detect low voltage on G13 Generator turn on control circuit when the ignition is ON and the engine is OFF, or when the charging system malfunctions. With the engine running, the ECM should detect high voltage on the G13 Generator turn on control circuit.

  1. The ignition ON, engine OFF for ignition on test.
  2. The engine is running for the run test.
  1. During the ignition on test, the ECM detects voltage on the G13 Generator turn on control circuit for 5 seconds.
  2. During the run test, the ECM detects low voltage on the G13 Generator turn on control circuit for 15 seconds.

DTC P0621 is a C type DTC.

DTC P0621 is a C type DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Verify that a test lamp illuminates between the G13 Generator terminal B+ X2 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF. Test for greater than 100 ohms between the B+ circuit and ground. If 100 ohms or less, repair the short to ground on the circuit. If greater than 100 ohms, replace the G13 Generator. If the test lamp illuminates
  2. Ignition OFF, disconnect the X1 harness connector at the G13 Generator, ignition ON.
  3. Test for 3.5 V or greater between the control circuit terminal 1 X1 and ground. If less than 3.5 V Ignition OFF, disconnect the harness connectors at the K20 Engine Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If greater the 2 ohms, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 Engine Control Module. If 3.5 V or greater Ignition OFF, disconnect the harness connectors at the K20 Engine Control Module. Test for less than 1 V between the control circuit and ground. If less than 1 V, replace the G13 Generator. If 1 V or greater, repair the short to voltage on the circuit.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Generator Replacement (V6)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for K20 Engine Control Module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
B+P0622P0621
ControlP0621P0621P0621
SignalP0622P0622P0622

The engine control module (ECM) uses the generator field duty cycle signal circuit, or F-terminal circuit, to monitor the duty cycle of the generator. The generator field duty cycle signal circuit connects to high side of the field windings in the generator. A pulse width modulated (PWM) high side driver in the voltage regulator turns the field windings ON and OFF. The ECM uses the PWM signal input to determine the generator load on the engine. This allows the ECM to adjust the idle speed to compensate for high electrical loads. The ECM monitors the status of the generator field duty cycle signal circuit. When the ignition is ON and the engine is OFF, the ECM should detect a duty cycle near 0 percent. When the engine is running, the duty cycle should be between 5-99 percent.

  1. Ignition ON engine OFF, for the Ignition ON test.
  2. Engine running, engine speed less than 3, 000 RPM for the RUN test.
  1. DTC P0621 is not set.
  2. Ignition ON engine OFF, the ECM detects a PWM signal that is greater than 65 percent for 5 seconds.
  3. Engine running, the ECM detects a PWM signal that is less than 5 percent for 15 seconds.

DTC P0622 is a C type DTC.

DTC P0622 is a C type DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Engine running, observe the scan tool GEN-F Terminal Signal Circuit parameter. The GEN-F Terminal Signal Circuit parameter should display between 5-99 percent.

  1. Verify that a test lamp illuminates between the G13 generator B+ terminal A X2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  2. Ignition OFF, disconnect the X1 harness connector at the G13 generator.
  3. Ignition ON, verify the scan tool ECM GEN-F Terminal Signal parameter displays less than 5 percent. If greater than the specified range, test the signal circuit terminal 2 for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Install a 3 A fused jumper wire between B+ and the signal circuit terminal 2.
  5. Verify the scan tool ECM GEN-F Terminal Signal parameter displays greater than 95 percent. If less than the specified range, test the signal circuit terminal 2 for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  6. If the circuit tests normal replace the G13 generator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator Replacement (V6)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
B+P0625P0625
SignalP0625P0625P0626
ControlP0621P0621P0621

The engine control module (ECM) uses the generator field duty cycle signal circuit, or F-terminal circuit, to monitor the duty cycle of the generator. The generator field duty cycle signal circuit connects to high side of the field windings in the generator. A pulse width modulated (PWM) high side driver in the voltage regulator turns the field windings ON and OFF. The ECM uses the PWM signal input to determine the generator load on the engine. This allows the ECM to adjust the idle speed to compensate for high electrical loads. The ECM monitors the status of the generator field duty cycle signal circuit. When the ignition is ON and the engine is OFF, the ECM should detect a duty cycle near 0%. When the engine is running, the duty cycle should be between 5-99%.

P0625

  1. The engine is running.
  2. The engine speed is less than 3 000 RPM.

P0626

  1. The engine is not running.
  2. The ignition is in the ON position.

P0625

The ECM detects a pulse width modulated (PWM) signal less than 5% for 15 s.

P0626

The ECM detects a pulse width modulated (PWM) signal greater than 65% for 15 s.

DTC P0625 and P0626 are C type DTCs.

DTC P0625 and P0626 are C type DTCs.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Engine running.
  2. Verify the scan tool GEN-F Terminal Signal Circuit parameter changes between 5 and 99 percent. If the parameter does not change Refer to Circuit/System Testing below. If the parameter changes
  3. All OK.
  1. Verify a test lamp illuminates between the G13 generator B+ circuit terminal X2 B+ and ground. If the test lamp does not illuminate and the circuit fuse is good Disconnect the B+ cable at the G13 generator. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for infinite resistance between the signal circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the G13 generator. If the test lamp illuminates
  2. Ignition OFF, disconnect the X1 harness connector at the G13 generator.
  3. Verify the scan tool ECM GEN-F parameter is less than 5 percent. If 5 percent or greater Ignition ON. Test for less than 1 V between the signal circuit terminal 2 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K20 engine control module. If less than 5 percent
  4. Install a 3 A fused jumper wire between the signal circuit terminal 2 and B+.
  5. Verify the scan tool ECM GEN-F Terminal Signal parameter is greater than 95 percent. If 95 percent or less Ignition OFF, disconnect the harness connector at the K20 engine control module. Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms Test for infinite resistance between the signal circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K20 engine control module. If greater than 95 percent.
  6. Replace the G13 generator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Generator Replacement (V6)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup and programming

Symptoms - Engine Electrical

Note. The following steps must be completed before using the symptom tables.

  1. Perform «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
  2. Review the system descriptions and operations in order to familiarize yourself with the system functions. Refer to one of the following system operations: «Battery Description and Operation»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid__battery-description-and-operation) «Charging System Description and Operation»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) «Electrical Power Management Description and Operation»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) «Starting System Description and Operation»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid__starting-system-description-and-operation)

Visual/Physical Inspection

  1. Inspect for aftermarket devices which could affect the operation of the starting and charging systems. Refer to «Checking Aftermarket Accessories»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
  2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

  1. «Battery Inspection/Test»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  2. «Battery Electrical Drain/Parasitic Load Test»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  3. «Charging System Test»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  4. «Generator Noise Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  5. «Starter Solenoid Does Not Click»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  6. «Starter Solenoid Clicks, Engine Does Not Crank»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  7. «Engine Cranks Slowly»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  8. «Starter Noise Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
WARNINGRefer to Battery Disconnect Warning .

Note. The battery test using the regionally available battery tester requires correct connections to the battery terminals. Ensure that battery tester clamps are connected directly to either the battery post or the battery cable terminal. Do not connect clamps to battery cable fasteners. Failure to obtain the correct connections during the test may result in a failed test on a good battery. Use the Out of Vehicle test for each battery when testing a vehicle with dual batteries.

Follow these instructions in order to avoid an incorrect diagnosis because of connections

  1. If testing the vehicle with the battery cables still connected, wiggle the battery tester clips on the terminal. This may cut through any coating or through any oxidation that may be present on the terminal.
  2. If correct connections to the battery terminals in the vehicle are in doubt, perform the following steps: Disconnect the negative battery cable. Disconnect the positive battery cable. Follow the instructions for testing a removed battery.
  3. If the tester displays a REPLACE BATTERY or BAD CELL-REPLACE result for a battery tested in the vehicle with the battery cables connected, perform the following steps: Disconnect the negative battery cable. Disconnect the positive battery cable. NOTE: Always write the test code displayed by the tester on the repair order for any warranty purposes. The number is a unique code that describes the test data for a particular battery at a particular time. The test code may occasionally repeat when you retest the same battery. More often, each test will result in a different code. Use the test code from the second, or Out of Vehicle test. Follow the instructions for testing a removed battery. Replace the battery only if the second test shows a REPLACE BATTERY or BAD CELL-REPLACE result. Use the test code from the second test for any warranty purposes.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

Battery Tester, for regionally available devices, refer to Special Tools .

WARNINGUnless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components. For Vehicles equipped with OnStar® (UE1) with Back Up Battery: The Back Up Battery is a redundant power supply to allow limited OnStar® functionality in the event of a main vehicle battery power disruption to the VCIM (OnStar®module). Do not disconnect the main vehicle battery or remove the OnStar® fuse with the ignition key in any position other than OFF. Retained accessory power (RAP) should be allowed to time out or be disabled (simply opening the driver door should disable RAP) before disconnecting power. Disconnecting power to the OnStar® module in any way while the ignition is On or with RAP activated may cause activation of the OnStar® Back-Up Battery (BUB) system and will discharge and permanently damage the back-up battery. Once the Back-Up Battery is activated it will stay on until it has completely discharged. The BUB is not rechargeable and once activated the BUB must be replaced.
  1. Verify the C1 battery case is not cracked, broken, or damaged, which may be indicated by battery acid leakage. If there is any apparent damage Replace the C1 battery. If there is no damage
  2. Verify the cold cranking amperage and amperage hour rating of the C1 battery. Refer to the manufacturer specifications on the battery label. If the C1 battery does not meet or exceed specifications Replace the C1 Battery. If the C1 Battery meets or exceeds specifications
  3. Verify that the battery cables are clean and tight. The battery terminal bolts should be torqued as specified in «Fastener Tightening Specifications»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid__fastener-tightening-specifications) . If the battery cables need to be cleaned or tightened Clean as required and tighten as specified. If the battery cables are clean and tight
  4. Install the battery tester and follow directions supplied by the tester.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Special Tools

EL 42000 Battery Tester

For equivalent regional tools, refer to Special Tools .

  1. For best results, use an automatic taper-rate battery charger with a voltage capability of 16 V.
  2. The charging area should be well ventilated.
  3. Do not charge a battery that appears to be frozen. Allow the battery to warm to room temperature and test it using the EL 42000 before charging.

Battery State of Charge

Note. Using voltage to determine the batteries state of charge is only accurate after the battery has been at rest for 24 hours. This is enough time for the acid in each cell to equalize. If the battery has been charged or discharged in the past 24 hours, the battery state of charge will only be an estimate.

The maintenance-free batteries state of charge is estimated by reading the voltage of the battery across the battery terminals. Because the voltage is affected by current flow into or out of the battery, the engine must be stopped and all electrical loads turned OFF, including parasitic loads, when checking the voltage. The voltage can also be affected if the battery has just been charged or discharged, so it is important to consider what has happened to the battery in the time just before testing. Use the following procedure to determine the batteries state of charge

  1. Be sure all electrical loads are turned OFF.
  2. Determine whether the battery has been used in a vehicle or charged within the past 12 hours. If the answer is no, the terminal voltage will be stabilized and no action is necessary before reading the voltage. Skip to step 3. If the answer is yes, terminal voltage will not be stabilized and you should wait 12 hours since the last time the battery was used.
  3. Estimate the battery temperature by determining the average temperature to which the battery has been exposed for the past 12 hours.
  4. Measure the battery voltage at the battery terminals. Refer to the following table to determine the state of charge according to the estimated battery temperature
Battery Voltage% Charge at 0°C (32°F)% Charge at 25°C (75°F)
12.75 V100%100%
12.7 V100%90%
12.6 V90%75%
12.45 V75%65%
12.2 V65%45%
12.0 V40%20%

Use the state of charge information as follows

  1. A battery with a state of charge that is below 65 percent must always be recharged before returning it to service or continuing storage.
  2. A battery with a state of charge that is 65 percent or greater is generally considered to be charged enough in order to be returned to normal service or in order to continue storage. However, if the battery is being used in slow traffic or with short drive times, or if the temperature is very hot or very cold, the battery should be fully charged, to at least 90 percent, before returning it to service or continuing storage.

Charging Time Required

The time required to charge a battery will vary depending upon the following factors

  1. The battery charger capacity-The higher the charger amperage, the less time it will take to charge the battery.
  2. The state of charge of the battery-A completely discharged battery requires more than twice as much charging time as a half charged battery. In a discharged battery with a voltage below 11 V, the battery has a very high internal resistance and may only accept a very low current at first. Later, as the charging current causes the acid content to increase in the electrolyte, the charging current will increase. Extremely discharged batteries may not activate the reversed voltage protection in some chargers. Refer to the manufacturer's instructions for operating this circuitry.
  3. The temperature of the battery-The colder the battery is, the more time it takes to recharge the battery. The charging current accepted by a cold battery is very low at first. As the battery warms, the charging current will increase.

Charging Procedure

CAUTIONTurn OFF the ignition when connecting or disconnecting the battery cables, the battery charger or the jumper cables. Failure to do so may damage the ECM/PCM or other electronic components.
CAUTIONRefer to Fastener Caution .

When charging side-terminal batteries with the battery cables connected, connect the charger to the positive cable bolt and to a ground located away from the battery. When charging side-terminal batteries with the battery cables disconnected, install the battery side terminal adapters and connect the charger to the adapters.

Tighten

Tighten the battery side terminal adapters to 15 Y (11 lb ft).

Use the following procedure to charge the battery

  1. Turn OFF the charger.
  2. Ensure that all of the battery terminal connections are clean and tight.
  3. Connect the charger positive lead to the battery positive terminal on the battery or the remote jumper stud underhood.
  4. Connect the negative charger lead to a solid engine ground or to a ground stud in the engine compartment that is connected directly to the battery negative terminal, but away from the battery. If the negative battery cable is disconnected and a terminal adapter is being used, connect directly to the adapter.
  5. Turn ON the charger and set to the highest setting for normal charging.
  6. Inspect the battery every half hour after starting the battery charger. Charge the battery until the taper-rate charger indicates that the battery is fully charged. Estimate the battery temperature by feeling the side of the battery. If it feels hot to the touch or its temperature is over 45°C (125°F), discontinue charging and allow the battery to cool before resuming charging.
  7. After charging, test the battery. Refer to «Battery Inspection/Test»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .

12 V Battery

The following procedure is for the 12 V battery only.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Components most likely to cause a parasitic draw on the vehicles battery are switches, relays, and control modules. After the ignition is turned OFF the control modules will begin to go to sleep (shut OFF). All control modules do not go to sleep at the same time, some may take up to 30 min or longer after turning the ignition off before going to sleep, like the HVAC and body control modules. Others such as the ON Star and keyless entry control modules may periodically wake up then go back to sleep. These are all normal conditions.

  1. Rule out any possible aftermarket equipment causing an unacceptable parasitic current drain. Aftermarket accessories installed into the courtesy lamp circuit can cause the inadvertent power timer in the body control module (BCM) to keep resetting. This may cause the BCM to remain awake and cause a current drain on the battery.
  2. Rule out customer driving habits such as regular short trips that do not allow enough time to properly charge the battery. Refer to «Battery Description and Operation»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid__battery-description-and-operation) .
  3. Verify that the battery and charging system are in proper working order. Refer to «Battery Charging»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) , and «Charging System Test»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  4. A battery discharging for no apparent reason while the vehicle is parked can be caused by an intermittent draw, such as a module waking up, or a continuous draw, such as a dome light or stuck relay.
  5. Some systems and modules such as OnStar®, and regulated voltage control, if equipped, are designed to wake up, perform a task, and go back asleep at regular intervals. Refer to «Body Control System Description and Operation»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#data-communications-system__body-control-system-description-and-operation) for the system or modules description and operation.
  6. An engine off natural vacuum evaporative test can occur if the engine control module (ECM) determines the drive cycle has met the appropriate criteria immediately after key off. The ECM will stay awake and the vent solenoid will stay energized for as long as 45 min. The typical current draw for this is about 1 A.
  7. Digital OnStar generator 6 and later vehicle communication interface module do not "wake up" every 10 min for the first 48 h as the generator 5 and prior. Generator 6 and later vehicle communication interface module current draw is very low, less than 40 mA, so the OnStar system is left in that state for up to the first 48 h. Parasitic draw of up to 40 mA with an occasional spike as high as 80 mA through the vehicle communication interface module for the first 48 h is normal.
  8. Some automatic climate control systems can remain in a semi awake state for up to three hours, actual draw amounts vary by vehicle platform but are typically not greater than 50 mA.
  9. An extremely low mA current level is consumed by the remote keyless entry receiver for monitoring purposes, actual system wake up only occurs when the fobs for the vehicle are used. When other devices on the same remote keyless entry operating frequency are activated, such as the 4 tire pressure monitoring sensors and other vehicle FOBs in the vicinity, the remote keyless entry receiver will have a 100 mA spike. These spikes are normal and occur too briefly to have a significant effect on battery drain. Competing signals may cause remote keyless entry performance issues such as jamming but should not cause excessive battery draw.
  10. If an excessive current draw is not present during initial testing, continue periodic testing over a 1-2 hour period to see if the current draw increases and stays above an unacceptable level.
  11. The battery run down time will vary depending on the batteries reserve capacity. If the reserve capacity is higher, then the battery run down time may be longer. If the reserve capacity is lower, then the battery run down time may be shorter. The graph below indicates roughly how many days a 690 cold cranking amperage battery with a 110 min. reserve capacity starting at 80 percent state of charge will last with a constant current draw until it reaches 50 percent state of charge. Differences in battery reserve capacity and temperature will affect the results.
Current DrainDays
25 mA33
50 mA16.5
75 mA11
100 mA8.25
250 mA3.3
500 mA1.65
750 mA1
1 A0.8
2 A0.4

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  3. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL 38758 Parasitic Draw Test Switch

For equivalent regional tools, refer to Special Tools .

Note. Most vehicle systems will go to sleep within 30 min but it can take up to 2 h before all systems power down allowing the parasitic draw test to pass. An occasional increase in the parasitic draw is normal as long as it returns within 1 s. Closing the door latches/ajar switch while leaving the doors open is recommended, this allows the vehicle systems to perform in a "doors closed" mode while allowing vehicle interior access that may be needed to complete the diagnostic steps. Locking doors will arm the vehicle content theft deterrent system if equipped. Failure to arm the system may cause a theft system fault to not be present during testing. There are many things that can prevent the vehicle from completely going to sleep and passing the parasitic draw test. Make sure all the conditions listed below are met before performing the parasitic current draw test. Ignition OFF Key out of the ignition switch - when not equipped with keyless access and start Retained Accessory Power OFF - open and close the driver door after ignition OFF Scan tool not communicating with a vehicle control module - in some cases it may need to be disconnected from the DLC All access doors closed Headlamps OFF - auto headlamps disabled Any delay lighting OFF If equipped with an under hood lamp disable it HVAC after blow OFF Any accessory that can work with ignition OFF inactive or OFF Wait up to 2 min or longer, after all other listed conditions are met

Using an Inductive Pickup Probe

  1. Connect an inductive pickup probe to the negative battery cable that can read down to 1 mA.
  2. Ignition OFF, as the vehicle systems shut down test for less than 30 mA of parasitic current drain. If greater than the specified range, refer to Circuit/System Testing below.

Using the EL 38758 Parasitic Draw Test Switch

  1. Ignition OFF, disconnect the battery negative cable from the battery. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  2. Turn the EL 38758 switch knob to the OFF position.
  3. Install the male end of the EL 38758 switch to the battery ground terminal.
  4. Install the battery negative cable to the female end of the EL 38758 switch.
  5. Turn the EL 38758 switch knob to the ON position.
  6. Road test the vehicle and activate all of the accessories such as the radio and air conditioning.
  7. Ignition OFF, connect a 10 A fused jumper wire to the test switch tool terminals.
  8. Turn the EL 38758 switch knob to the OFF position. The current now flows through the jumper wire.
  9. Check the fuse in the jumper wire. The fuse should be OK. Failed: If the jumper wire fuse is blown, refer to Circuit/System Testing below. Passed
  10. Turn the EL 38758 switch knob to the ON position. Remove the fused jumper wire.
  11. Connect a DMM set to the 10 A DC scale between the test switch tool terminals.
  12. Turn the EL 38758 switch knob to the OFF position. The current now flows through the DMM.
  13. As the vehicle systems shut down test for less than 30 mA of parasitic current drain. If greater than the specified range, refer to Circuit/System Testing below.

Note. Removing or installing a fuse, relay, or connector, to determine the area causing high parasitic draw may wake up control modules. You must wait for the control modules to go back to sleep before retesting. It is best to install any removed or disconnected components after the diagnosis is completed. Fuses for power mode master components such as the BCM should be removed last to avoid misdiagnosis. If a scan tool is connected to the DLC, either disconnect it or subtract the scan tool current draw from the DMM reading to get the actual vehicle parasitic current draw.

If the vehicle has an unacceptable amount of parasitic current draw, remove each fuse one at a time until the current draw falls to an acceptable level. A drop of more than 10-20 mA, when disabling a single system or circuit, is an indication of an overly high current draw that could be causing the battery drain. Refer to Power Distribution Schematics to diagnose exactly which circuit of the suspect system is causing the high parasitic drain. The following is a list of common components that could cause a high current draw

  1. Stuck switch
  2. Stuck relay
  3. Control module

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for control module replacement, programming and setup

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Engine running, observe the charge indicator on the instrument cluster or message in the driver information center display. The charge indicator on the instrument cluster should be turned OFF and the driver information center display should not display any charging system message.

  1. Ignition ON, verify that no G13 Generator or B18 battery current sensor DTCs are set that would cause a charging system concern. If DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Ignition OFF, measure the voltage across the battery terminals. The voltage should read 12.0 V or greater at room temperature. If not within the specified value, refer to «Battery Inspection/Test»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  3. Engine ON, increase engine speed to 2, 500 RPM. Verify the battery voltage is between 12.6-15.0 V. If not within specified range, replace the G13 generator.
  4. Engine ON, increase engine speed to 2, 500 RPM. Turn ON all vehicle accessories. Verify the battery voltage is between 12.6-15.0 V. If not within specified range, replace the G13 generator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Noise from a generator may be due to electrical or mechanical noise. Electrical noise or magnetic whine usually varies with the electrical load placed on the generator and is a normal operating characteristic of all generators. When diagnosing a noisy generator, it is important to remember that loose or misaligned components around the generator may transmit the noise into the passenger compartment and that replacing the generator may not solve the problem.

  1. Start the engine. Verify the noise can be heard. Compare the concern to a similar vehicle.
  2. Perform a charging system test. Verify that the generator is charging properly.
  3. Inspect the generator, generator mounting, wiring harness, heater hoses, A/C lines, or other accessory equipment that may be misrouted or be the cause of noise being transmitted into the passenger compartment.
  4. Ignition OFF, remove the engine drive belt. Verify the generator, A/C compressor, water pump pulley, power steering pump, idler pulley, and tensioner pulley spin freely. If any of the pulleys do not spin freely, replace the affected component.
  5. Start the engine, with the drive belt removed. Verify that the noise goes away. Operate the engine for no longer than 30-40 seconds. If the noise is still present, the generator is not the cause of the noise.
  6. Loosen all generator mounting bolts and ensure the generator is properly aligned. Tighten the mounting bolts to specification, refer to «Generator Replacement (V6)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Drive Belt Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-24l__drive-belt-replacement) for the 2.2L or 2.4L engines
  2. «Drive Belt Tensioner Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-24l__drive-belt-tensioner-replacement) for the 2.2L or 2.4L engines
  3. «Drive Belt Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle) for the 2.8L, 3.0L, 3.2L and 3.6L engines
  4. «Drive Belt Tensioner Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle) for the 2.8L, 3.0L, 3.2L and 3.6L engines
  5. «Drive Belt Idler Pulley Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle) for the 2.8L, 3.0L, 3.2L and 3.6L engines
  6. «Generator Replacement (V6)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
B+11
Signal21
Relay Coil Control Terminal 8513
Starter Control Terminal 87113
Ground1
1. Starter Solenoid Does Not Click 2. Cranks In Any Gear 3. Cranks All The Time

When the ignition mode switch is placed in the START position, a discrete signal is supplied to the body control module (BCM) notifying it that the ignition is in the START position. The BCM then sends a serial data message to the engine control module (ECM) that crank has been requested. The ECM then verifies that the clutch is fully depressed or the automatic transmission is in Park/Neutral. If it is, the ECM then supplies 12 V to the control circuit of the starter relay. When this occurs, battery voltage is supplied through the switch of the starter relay to the starter solenoid.

Schematic Reference

  1. «Starting and Charging Schematics»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  2. «Automatic Transmission Controls Schematics»(/buick/lacrosse/ii-2009-2013/remont/automatic-trans/#automatic-transmission-6t70-wiring-schematic-diagrams) for the MH2 and MH4 transmission
  3. «Automatic Transmission Controls Schematics»(/buick/lacrosse/ii-2009-2013/remont/automatic-trans/#automatic-transmission-6t40-wiring-schematic-diagrams) for the MH7 transmission

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, verify that no ignition, starter relay, brake pedal position sensor, immobilizer, or automatic transmission DTCs are set that would cause the ECM to disable engine starting. If DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Ignition ON, observe the scan tool BCM 5 V Ignition Switch parameter. Place the ignition switch in the crank position, the parameter should display Crank Request. If not the specified value, refer to «Power Mode Mismatch»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures) .
  3. Transmission range selector in park, verify the scan tool TCM Internal Mode Switch parameters display Park. If the TCM Internal Mode Switch parameter does not indicate Park. Refer to «Transmission Internal Mode Switch Logic»(/buick/lacrosse/ii-2009-2013/remont/automatic-trans/#automatic-transmission-6t70-specifications__transmission-internal-mode-switch-logic) , for the MH2 or MH4 transmission or «Transmission Internal Mode Switch Logic»(/buick/lacrosse/ii-2009-2013/remont/automatic-trans/#automatic-transmission-6t40-specifications__transmission-internal-mode-switch-logic) for the MH7 transmission.
  4. Transmission in park or neutral, attempt to start the vehicle. The crank relay should click and the engine should begin cranking. If the KR27 starter relay does not click or the engine does not crank, refer to Circuit/System Testing below.
  1. Ignition ON, with a scan tool verify the ECM Ignition 1 Signal parameter is greater than 10 V. If less than the specified range, test the ECM ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  2. Ignition OFF, disconnect the KR27 starter relay.
  3. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5.0 ohms between the relay ground circuit terminal 86 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse or starter fuse is open, test the control circuit terminal 87 for a short to ground.
  5. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit terminal 87 for a short to voltage.
  6. Ensure the parking brake is applied and the T12 transmission is in PARK. Momentarily install a 30 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the M64 starter motor is activated. If the M64 starter motor does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the M64 starter motor.
  7. Connect a test lamp between the control circuit terminal 85 and the ground circuit terminal 86.
  8. Transmission in park/neutral, command the starter relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  9. If all circuits test normal, test or replace the KR27 starter relay.

Relay Test

  1. Ignition OFF, disconnect the KR27 starter relay.
  2. Test for 60-180 ohms between terminals 85 and 86. If not within the specified range, replace the relay.
  3. Test for infinite resistance between the following terminals: 30 and 86 30 and 87 30 and 85 85 and 87 If not the specified value, replace the relay.
  4. Install a 20 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than specified range, replace the relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Manual Shift Detent Lever with Shaft Position Switch Assembly Replacement»(/buick/lacrosse/ii-2009-2013/remont/automatic-trans/#automatic-transmission-6t40-repair-instructions-on-vehicle)
  2. «Relay Replacement (Within an Electrical Center)»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions__relay-replacement-within-an-electrical-center) , «Relay Replacement (Attached to Wire Harness)»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, measure and record the battery voltage at the C1 Battery terminals.
  2. Verify the measured voltage is between 12.0-15.0 V. If voltage is less than 12.0 V or greater than 15.0 V Refer to «Battery Inspection/Test»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) . If voltage is between 12.0-15.0 V
  3. Remove the drive belts. Refer to «Drive Belt Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-24l__drive-belt-replacement) , for the LAF engine or «Drive Belt Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle) for the LF1 or LLT engine.
  4. Verify the crankshaft rotates rotate the crankshaft by hand using the appropriate tools. If the crankshaft does not rotate Refer to «Engine Will Not Crank - Crankshaft Will Not Rotate»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-24l__engine-will-not-crank-crankshaft) . If the crankshaft rotates
  5. Verify the engine does not crank when attempting to start the vehicle. If the engine cranks Inspect the engine and belt drive system for mechanical binding, seized engine, or seized generator. If the engine does not crank
  6. Verify that a test lamp illuminates between the M64 starter motor B+ terminal A X2 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF. Test for greater than 100 ohms between the B+ circuit and ground. If 100 ohms or less, repair the short to ground on the circuit. If greater than 100 ohms, replace the M64 starter motor. If the test lamp illuminates
  7. Test for less than 0.5 V between the positive battery post and terminal A X2 at the M64 starter motor with the ignition in the START position. If 0.5 V or greater Replace the positive battery cable. If less than 0.5 V
  8. Test for less than 0.5 V between the negative battery post and the M64 starter motor case with the ignition in the START position. If 0.5 V or greater Replace the negative battery cable. less than 0.5 V
  9. Replace the M64 starter motor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Battery Positive and Negative Cable Replacement (V6)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) , «Battery Positive and Negative Cable Replacement (LUK)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  2. «Starter Replacement (V6)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) , «Starter Replacement (LUK)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, measure and record the battery voltage at the C1 terminals. The voltage should be between 12.0-15.0 V. If not within the specified range, refer to «Battery Inspection/Test»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  2. Remove the drive belts. Refer to «Drive Belt Tensioner Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-24l__drive-belt-tensioner-replacement) , or «Drive Belt Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-24l__drive-belt-replacement) , for the LAF engine, or «Drive Belt Tensioner Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle) , or «Drive Belt Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle) for the LF1 or LLT engine.
  3. Ignition Start, verify the engine does not crank normal. If the engine cranks normal, inspect the engine and belt drive system for mechanical binding, seized engine, or seized generator.
  4. Verify that a test lamp illuminates between the M64 starter motor B+ terminal A X2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  5. Test for less than 0.5 V between the positive battery cable and terminal A X2 at the M64 starter motor as ignition is switched to start position. If greater than the specified value, replace the positive battery cable.
  6. Test for less than 0.5 V between the negative battery cable and the M64 starter motor case as ignition is switched to start position. If greater than the specified value, replace the negative battery cable.
  7. If all circuits test normal, replace the M64 starter motor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Battery Positive and Negative Cable Replacement (V6)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) , «Battery Positive and Negative Cable Replacement (LUK)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  2. «Starter Replacement (V6)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) , «Starter Replacement (LUK)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)
  1. Remove the flywheel inspection cover.
  2. Inspect the flywheel for the following: Loose flywheel bolts Chipped gear teeth Missing gear teeth Bent flywheel If not within specifications, secure the flywheel bolts or replace the flywheel. If all inspections were within specification, replace the starter motor.
  1. «Fastener Tightening Specifications (LAF, LEA, or LUK)»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-24l__fastener-tightening-specifications-luk) for the 2.2L and 2.4L engine
  2. «Automatic Transmission Flex Plate Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-24l) for the 2.2L and 2.4L engine
  3. «Fastener Tightening Specifications»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-specifications__fastener-tightening-specifications) for the 2.8L, 3.0L, 3.2L, 3.6L engine
  4. «Engine Flywheel Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle) for the 2.8L, 3.0L, 3.2L, 3.6L engine
  5. «Starter Replacement (V6)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) , «Starter Replacement (LUK)»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid)

Scheme 3

Scheme 3: Battery Negative Cable Disconnection and Connection
Scheme 3: Battery Negative Cable Disconnection and Connection
CalloutComponent Name
Preliminary Procedures Turn the ignition OFF. Record radio and engine oil life resets.
1Battery Cover
2Battery Negative Cable Fastener WARNING: Refer to Battery Disconnect Warning . CAUTION: Refer to Fastener Caution . Tighten 4.5 N.m (40 lb in)
3Battery Negative Cable
WARNING
Refer to Battery Disconnect Warning .
CAUTION
Refer to Fastener Caution .

Battery Negative Cable Disconnection and Connection

Removal Procedure

  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  2. Disconnect the body harness electrical connector (2) from the battery current sensor.
  3. Remove the negative battery cable frame ground ring terminal nut (3) and detach the negative battery ring terminal.
  4. Detach the battery current sensor (2) from the current sensor bracket (3).
  5. Slide the sensor from the negative battery cable (1).

Installation Procedure

  1. Slide the NEW battery current sensor (2) up onto the battery cable (1).
  2. Attach the sensor to the battery current sensor bracket (3).
  3. Install the negative battery cable frame ground and tighten nut (3) to 12 N.m (9 lb ft).
  4. Connect the body harness electrical connector (2) to the battery current sensor.
  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  2. Open the battery fuse block cover (1).
  3. Remove the battery positive nut (2) from battery fuse block and detach retainers from the battery tray.
  4. Remove the battery negative nut (1) and terminal (2) from the left front frame rail.
  5. Remove the nut (1) from underneath the protective boot behind the generator.
  6. Remove the battery positive cable terminal from the generator.
  7. Remove the starter shield bolt and shield.
  8. Remove the starter solenoid nut (2) and battery positive cable terminal from the starter solenoid.
  9. Remove the negative battery cable bolt (3) and terminal from the back of the left cylinder head.
  10. Remove the battery positive and negative cable retainer clip nut (4).
  11. Remove the battery positive and negative cable.
  1. Install the retainers that hold the battery cable harness to the battery tray.
  2. Install the battery cable harness to the engine block with retainer (4).
  3. Install the negative battery cable terminal and bolt (3) to the left rear cylinder head. Tighten to 25 N.m (18 lb ft).
  4. Install the battery positive cable terminal and nut (2) to the starter solenoid. Tighten to 25 N.m (18 lb ft).
  5. Install the starter heat shield and tighten to 20 N.m (15 lb ft)
  6. Install the battery positive cable terminal and nut (1) to the back of the generator. Tighten to 20 N.m (15 lb ft).
  7. Install the battery negative cable terminal (2) and nut (1) to the left front frame rail. Tighten to 25 N.m (18 lb ft).
  8. Install the positive battery cable terminal and nut (2) to the battery fuse block. Tighten to 12 N.m (106 lb in).
  9. Close battery fuse block cover (1) and install battery negative cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  2. Release the tabs (1) and open the battery fuse block cover (2).
  3. Remove the battery positive nut (1) and the cable (2), from the battery fuse block. Unclip the battery positive cable from the battery tray.
  4. Remove the battery negative nut (1) and terminal (2) from the left front frame rail.
  5. Remove the battery positive and negative cable (1) from the ground frame stud.
  6. Remove the battery positive and negative cable bolt (1) and the ground terminal (2).
  7. Remove the starter solenoid nut (1) and battery positive cable (2) from the starter solenoid.
  8. Remove the battery positive and negative cable from the engine compartment.
  1. Install the battery positive cable (2) to the battery fuse block and tighten the nut (1) to 10 N.m (88 lb in).
  2. Install the battery positive and negative cable (1) to the frame rail stud.
  3. Install the negative battery cable terminal (2) and tighten the nut (1) to 12 N.m (9 lb ft).
  4. Install the battery positive and negative cable terminal and nut (1) to the starter solenoid. Tighten to 10 N.m (88 lb in).
  5. Install the battery positive and negative cable (2) to the engine block. Tighten the bolt (1) to 25 N.m (18 lb ft).
  6. Close battery fuse block cover (2) and connect battery negative cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .

Scheme 4

Scheme 4: Battery Negative Cable Replacement
Scheme 4: Battery Negative Cable Replacement
CalloutComponent Name
Preliminary Procedure Turn the ignition OFF. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .
1Body Harness Ground Fastener CAUTION: Refer to Fastener Caution . Tighten 9 (80 lb in)
2Battery Current Sensor Connector
3Battery Negative Cable Frame Ground Nut Tighten 25 (18 lb ft)
4Battery Negative Cable Procedure: Note the location of the current sensor. Cut the tape retaining the battery current sensor to the battery negative cable. Slide negative battery cable through current sensor. Transfer the current sensor to the NEW battery negative cable, in the same location.
CAUTION
Refer to Fastener Caution .

Battery Negative Cable Replacement

Scheme 5

Scheme 5: Battery Positive Fuse Block Cable Replacement
Scheme 5: Battery Positive Fuse Block Cable Replacement
CalloutComponent Name
Preliminary Procedure Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection . Open the battery fuse block cover.
1Nut CAUTION: Refer to Fastener Caution . Tighten 4.5 N.m (44 lb in)
2Nut Tighten 20 N.m (15 lb ft)
3Battery Positive Fuse Block Cable
CAUTION
Refer to Fastener Caution .

Battery Positive Fuse Block Cable Replacement

  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  2. Open the battery fuse block cover (2) with the release tab (1).
  3. Release the tabs and open the battery fuse block cover. Remove the battery positive cable fastener and cable, from the battery fuse block.
  4. Remove the battery fuse block cable clamp fastener (3) and the battery hold-down strap (4).
  5. Remove the battery fuse block (2) with the retainers (1) and set aside.
  6. Remove the battery retainer fastener (1) and the retainer (2).
  7. Remove the battery (1) from the engine compartment.
  1. Install the battery (1) into position on the battery tray.
  2. Install the battery retainer (2) and tighten the fastener (1) to 10 N.m (88 lb in).
  3. Install the battery fuse block (2) to the battery with the retainers (1).
  4. Install the battery positive cable (2) to the battery fuse block and tighten the fastener (1) to 10 N.m (88 lb in).
  5. Install the battery hold-down strap (4) to the battery positive post.
  6. Install the battery positive clamp to the post and tighten the fastener (3) to 4.5 N.m (44 lb in).
  7. Connect the battery negative cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  8. Close the cover (2) on the battery fuse block.
  9. Install the battery cover (2) with the retaining tabs (1).

Scheme 6

Scheme 6: Battery Tray Replacement
Scheme 6: Battery Tray Replacement
CalloutComponent Name
Preliminary Procedure Remove the battery. Refer to Battery Replacement . Remove the engine control module. Refer to Engine Control Module Replacement . Remove battery current sensor from battery tray bracket, if necessary.
1Battery Tray Bolt (Qty: 3) CAUTION: Refer to Fastener Caution . Tighten 20 N.m (15 lb ft)
2Battery Tray TIP: Unclip harnesses as necessary.
CAUTION
Refer to Fastener Caution .

Battery Tray Replacement

  1. Turn OFF the ignition.
  2. Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  3. Remove the heat shield (2) from the starter.
  4. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#general-information__lifting-and-jacking-the-vehicle)
  5. Disconnect the knock sensor connector.
  6. Remove the battery positive nut (1) and the engine harness connector (2), from the starter solenoid (3).
  7. Remove the starter motor bolts (1).
  8. Remove the starter motor (2).
  1. Install the starter motor (2).
  2. Install the starter motor mounting bolts. Tighten to 58 N.m (43 lb ft).
  3. Install the battery positive cable and engine harness connector to the starter. Tighten the battery positive cable nut (1) to 25 N.m (18 lb ft).
  4. Install the engine harness connector to the starter solenoid.
  5. Install the starter heat shield (2) and tighten the bolt (1) to 7 N.m (62 lb in).
  6. Connect the knock sensor connector.
  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#general-information__lifting-and-jacking-the-vehicle) .
  3. Remove the secondary air injection pump, if equipped. Refer to «Secondary Air Injection Pump Replacement»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-24l-repair-instructions) .
  4. Disconnect the engine wiring harness electrical connector (1) from the starter.
  5. Remove the positive battery cable to starter motor nut (1).
  6. Remove the positive battery cable lead (2) from the starter motor.
  7. Remove the starter motor bolts and starter.
  1. Install the starter motor and bolts and tighten to 53 N.m (39 lb ft).
  2. Install the positive battery cable lead (2) to the starter motor.
  3. Install the positive battery cable to starter motor nut (1) and tighten to 10 N.m (89 lb in).
  4. Connect the engine wiring harness electrical connector (1) to the starter.
  5. Lower the vehicle.
  6. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  7. Install the secondary air injection pump. Refer to «Secondary Air Injection Pump Replacement»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-24l-repair-instructions) .

Scheme 7

Scheme 7: Generator Bracket Replacement
Scheme 7: Generator Bracket Replacement
CalloutComponent Name
Preliminary Procedures Disconnect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection . Remove the starter generator. Refer to Starter Generator Replacement . Reposition the A/C compressor. Refer to Air Conditioning Compressor Replacement (V6) , Air Conditioning Compressor Replacement (LUK) .
1Bolt (Qty: 3) CAUTION: Refer to Fastener Caution . Tighten 58 N.m (43 lb ft)
2Generator Bracket
CAUTION
Refer to Fastener Caution .

Generator Bracket Replacement

  1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .
  2. Reposition the positive battery cable boot at the generator terminal.
  3. Disconnect the engine harness electrical connector (1) from the generator.
  4. Remove the positive battery cable nut (2) at the generator.
  5. Remove the positive battery cable terminal (3) from the generator.
  6. Remove the drive belt. Refer to «Drive Belt Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle) .
  7. Remove the idler pulley bolt (1) and idler pulley (2). Refer to «Drive Belt Idler Pulley Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle) .
  8. Remove the generator bolts (3).
  9. Remove the generator (4).
  1. Position the generator (4) to the engine.
  2. Loosely install the generator bolts (3).
  3. Install the idler pulley. Refer to «Drive Belt Idler Pulley Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle) .
  4. Tighten the generator bolts to 50 N.m (37 lb ft).
  5. Install the drive belt. Refer to «Drive Belt Replacement»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle) .
  6. Connect the engine harness electrical connector (1) to the generator.
  7. Install the positive battery cable terminal (3) to the generator.
  8. Install the positive battery cable nut (2) at the generator and tighten to 20 N.m (15 lb ft).
  9. Position the positive battery cable boot at the generator terminal.
  10. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/buick/lacrosse/ii-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-except-hybrid) .

Battery Description and Operation

WARNINGBatteries produce explosive gases, contain corrosive acid, and supply levels of electrical current high enough to cause burns. Therefore, to reduce the risk of personal injury when working near a battery: Always shield your eyes and avoid leaning over the battery whenever possible. Do not expose the battery to open flames or sparks. Do not allow the battery electrolyte to contact the eyes or the skin. Flush immediately and thoroughly any contacted areas with water and get medical help. Follow each step of the jump starting procedure in order. Treat both the booster and the discharged batteries carefully when using the jumper cables.

Note. Because of the materials used in the manufacture of automotive lead acid batteries, dealers and service shops that handle them are subject to various regulations issued by OSHA, EPA, DOT, and various state or local agencies. Other regulations may also apply in other locations. Always know and follow these regulations when handling batteries.

Batteries that are no longer wanted must be disposed of by an approved battery recycler and must never be thrown in the trash or sent to a landfill.

Batteries that are not part of the vehicle itself, not the battery under the hood, must only be transported on public streets for business purposes via approved hazardous material transportation procedures.

Battery storage, charging and testing facilities in repair shops must meet various requirements for ventilation, safety equipment, material segregation, etc.

The maintenance free battery is standard. There are no vent plugs in the cover. The battery is completely sealed except for 2 small vent holes in the side. These vent holes allow the small amount of gas that is produced in the battery to escape.

The battery has 3 functions as a major source of energy

  1. Engine cranking
  2. Voltage stabilizer
  3. Alternate source of energy with generator overload

Battery Low Start Vehicle Message

The body control module (BCM) monitors battery positive voltage to determine battery state of charge. If one or more of the BCM battery positive voltage terminals measure less than approximately 11.6V compared to the BCM ground circuits, this message will display and four chimes may sound. Start the vehicle immediately. If the vehicle is not started and the battery continues to discharge, the climate controls, heated seats, and audio systems will shut off and the vehicle may require a jump start. These systems will function again after the vehicle is started.

Battery Ratings

A battery has 2 ratings

  1. Cold cranking amperage
  2. Amperage hours

When a battery is replaced use a battery with similar ratings. See battery specification label on the original battery.

Amperage Hours

The amperage hour rating tells you how much amperage is available when discharged evenly over a 20 hour period. The amperage hour rating is cumulative, so in order to know how many constant amperage the battery will output for 20 h, you have to divide the amperage hour rating by 20. Example: If a battery has an amperage hour rating of 74, dividing by 20 = 3.75. Such a battery can carry a 3.75 A load for 20 hours before dropping to 10.5 V. (10.5 V is the fully discharged level, at which point the battery needs to be recharged.) A battery with an amperage hour rating of 55 will carry a 2.75 A load for 20 hours before dropping to 10.5 V.

Cold Cranking Amperage

The cold cranking amperage is an indication of the ability of the battery to crank the engine at cold temperatures. The cold cranking amperage rating is the minimum amperage the battery must maintain for 30 seconds at -18°C (0°F) while maintaining at least 7.2 V. See battery label for the cold cranking amperage rating of this battery.

Electrical Power Management Overview

The electrical power management system is designed to monitor and control the charging system and send diagnostic messages to alert the driver of possible problems with the battery and generator. This electrical power management system primarily utilizes existing on-board computer capability to maximize the effectiveness of the generator, to manage the load, improve battery state-of-charge and life, and minimize the system's impact on fuel economy. The electrical power management system performs 3 functions

  1. It monitors the battery voltage and estimates the battery condition.
  2. It takes corrective actions by boosting idle speeds, and adjusting the regulated voltage.
  3. It performs diagnostics and driver notification.

The battery condition is estimated during ignition-off and during ignition-on. During ignition-off the state-of-charge of the battery is determined by measuring the open-circuit voltage. The state-of-charge is a function of the acid concentration and the internal resistance of the battery, and is estimated by reading the battery open circuit voltage when the battery has been at rest for several hours.

The state-of-charge can be used as a diagnostic tool to tell the customer or the dealer the condition of the battery. Throughout ignition-on, the algorithm continuously estimates state-of-charge based on adjusted net amp hours, battery capacity, initial state-of-charge, and temperature.

While running, the battery degree of discharge is primarily determined by a battery current sensor, which is integrated to obtain net amp hours.

In addition, the electrical power management function is designed to perform regulated voltage control to improve battery state-of-charge, battery life, and fuel economy. This is accomplished by using knowledge of the battery state-of-charge and temperature to set the charging voltage to an optimum battery voltage level for recharging without detriment to battery life.

The Charging System Description and Operation is divided into 3 sections. The first section describes the charging system components and their integration into the electrical power management. The second section describes charging system operation. The third section describes the instrument panel cluster operation of the charge indicator, driver information center messages, and voltmeter operation.

Charging System Components

Generator

The generator is a serviceable component. If there is a diagnosed failure of the generator it must be replaced as an assembly. The engine drive belt drives the generator. When the rotor is spun it induces an alternating current (AC) into the stator windings. The AC voltage is then sent through a series of diodes for rectification. The rectified voltage has been converted into a direct current (DC) for use by the vehicles electrical system to maintain electrical loads and the battery charge. The voltage regulator integral to the generator controls the output of the generator. It is not serviceable. The voltage regulator controls the amount of current provided to the rotor. If the generator has field control circuit failure, the generator defaults to an output voltage of 13.8 V.

Body Control Module (BCM)

The body control module (BCM) is a GMLAN device. It communicates with the engine control module (ECM) and the instrument panel cluster for electrical power management (electrical power management) operation. The BCM determines the output of the generator and sends the information to the ECM for control of the generator turn on signal circuit. It monitors the generator field duty cycle signal circuit information sent from the ECM for control of the generator. It monitors a battery current sensor, the battery positive voltage circuit, and estimated battery temperature to determine battery state of charge. The BCM performs idle boost.

Battery Current Sensor

The battery current sensor is a serviceable component that is connected to the negative battery cable at the battery. The battery current sensor is a 3-wire hall effect current sensor. The battery current sensor monitors the battery current. It directly inputs to the BCM. It creates a 5-volt pulse width modulation (PWM) signal of 128 Hz with a duty cycle of 0-100 percent. Normal duty cycle is between 5-95 percent. Between 0-5 percent and 95-100 percent are for diagnostic purposes.

Engine Control Module (ECM)

When the engine is running, the generator turn-on signal is sent to the generator from the ECM, turning on the regulator. The generator's voltage regulator controls current to the rotor, thereby controlling the output voltage. The rotor current is proportional to the electrical pulse width supplied by the regulator. When the engine is started, the regulator senses generator rotation by detecting AC voltage at the stator through an internal wire. Once the engine is running, the regulator varies the field current by controlling the pulse width. This regulates the generator output voltage for proper battery charging and electrical system operation. The generator field duty terminal is connected internally to the voltage regulator and externally to the ECM. When the voltage regulator detects a charging system problem, it grounds this circuit to signal the ECM that a problem exists. The ECM monitors the generator field duty cycle signal circuit, and receives control decisions based on information from the BCM.

Instrument Panel Cluster

The instrument panel cluster provides the customer notification in case a concern with the charging system. There are 2 means of notification, a charge indicator and a driver information center message of SERVICE BATTERY CHARGING SYSTEM if equipped.

Charging System Operation

The purpose of the charging system is to maintain the battery charge and vehicle loads. There are 6 modes of operation and they include

  1. Battery Sulfation Mode
  2. Charge Mode
  3. Fuel Economy Mode
  4. Headlamp Mode
  5. Start Up Mode
  6. Voltage Reduction Mode

The engine control module (ECM) controls the generator through the generator turn ON signal circuit. The ECM monitors the generator performance though the generator field duty cycle signal circuit. The signal is a pulse width modulation (PWM) signal of 128 Hz with a duty cycle of 0-100 percent. Normal duty cycle is between 5-95 percent. Between 0-5 percent and 95-100 percent are for diagnostic purposes. The following table shows the commanded duty cycle and output voltage of the generator

Commanded Duty CycleGenerator Output Voltage
10%11 V
20%11.56 V
30%12.12 V
40%12.68 V
50%13.25 V
60%13.81 V
70%14.37 V
80%14.94 V
90%15.5 V

The generator provides a feedback signal of the generator voltage output through the generator field duty cycle signal circuit to the ECM. This information is sent to the body control module (BCM). The signal is PWM signal of 128 Hz with a duty cycle of 0-100 percent. Normal duty cycle is between 5-99 percent. Between 0-5 percent and 100 percent are for diagnostic purposes.

Battery Sulfation Mode

The BCM will enter this mode when the interpreted generator output voltage is less than 13.2 V for 45 minutes. When this condition exists the BCM will enter Charge Mode for 2-3 minutes. The BCM will then determine which mode to enter depending on voltage requirements.

Charge Mode

The BCM will enter Charge Mode when ever one of the following conditions are met.

  1. The wipers are ON for more than 3 seconds.
  2. GMLAN (Climate Control Voltage Boost Mode Request) is true, as sensed by the HVAC control head. High speed cooling fan, rear defogger and HVAC high speed blower operation can cause the BCM to enter the Charge Mode.
  3. The estimated battery temperature is less than 0°C (32°F).
  4. Battery State of Charge is less than 80 percent.
  5. Vehicle speed is greater than 145 km/h (90 mph)
  6. Current sensor fault exists.
  7. System voltage was determined to be below 12.56 V

When any one of these conditions is met, the system will set targeted generator output voltage to a charging voltage between 13.9-15.5 V, depending on the battery state of charge and estimated battery temperature.

Fuel Economy Mode

The BCM will enter Fuel Economy Mode when the estimated battery temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is less than 15 amperes and greater than -8 amperes, and the battery state-of-charge is greater than or equal to 80 percent. Its targeted generator output voltage is the open circuit voltage of the battery and can be between 12.5-13.1 V. The BCM will exit this mode and enter Charge Mode when any of the conditions described above are present.

Headlamp Mode

The BCM will enter Headlamp Mode when ever the headlamps are ON (high or low beams). Voltage will be regulated between 13.9-14.5 V.

Start Up Mode

When the engine is started the BCM sets a targeted generator output voltage of 14.5 V for 30 seconds.

Voltage Reduction Mode

The BCM will enter Voltage Reduction Mode when the calculated ambient air temperature is above 0°C (32°F). The calculated battery current is less than 1 ampere and greater than -7 amperes, and the generator field duty cycle is less than 99 percent. Its targeted generator output voltage is 12.9 V. The BCM will exit this mode once the criteria are met for Charge Mode.

Instrument Panel Cluster Operation

Charge Indicator Operation

The instrument panel cluster illuminates the charge indicator and displays a warning message in the driver information center if equipped, when the one or more of the following occurs

  1. The engine control module (ECM) detects that the generator output is less than 11 V or greater than 16 V. The instrument panel cluster receives a GMLAN message from the ECM requesting illumination.
  2. The instrument panel cluster determines that the system voltage is less than 11 V or greater than 16 V for more than 30 seconds. The instrument panel cluster receives a GMLAN message from the body control module (BCM) indicating there is a system voltage range concern.
  3. The instrument panel cluster performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 3 seconds.

Display Message: BATTERY NOT CHARGING SERVICE CHARGING SYSTEM or SERVICE BATTERY CHARGING SYSTEM

The BCM and the ECM will send a serial data message to the driver information center for the BATTERY NOT CHARGING SERVICE CHARGING SYSTEM or SERVICE BATTERY CHARGING SYSTEM message to be displayed. It is commanded ON when a charging system DTC is a current DTC. The message is turned OFF when the conditions for clearing the DTC have been met.

Electrical Power Management

The electrical power management is used to monitor and control the charging system and alert the driver of possible problems within the charging system. The electrical power management system makes the most efficient use of the generator output, improves the battery state-of-charge, extends battery life, and manages system electrical loads.

The load shed operation is a means of reducing electrical loads during a low voltage or low battery state-of-charge condition.

The idle boost operation is a means of improving generator performance during a low voltage or low battery state-of-charge condition.

Each electrical power management function, either idle boost or load shed, is discrete. No two functions are active at the same time. Idle boost is activated in incremental steps, idle boost 1 must be active before idle boost 2 can be active. The criteria used by the body control module (BCM) to regulate electrical power management are outlined below

FunctionBattery Temperature CalculationBattery Voltage CalculationAmp-Hour CalculationAction Taken
Idle Boost 1 StartLess Than -15°C (5°F)Less Than 13 VFirst level Idle boost requested
Idle Boost 1 StartBattery has a net loss greater than 0.6 AHFirst level Idle boost requested
Idle Boost 1 StartLess Than 10.9 VFirst level Idle boost requested
Idle Boost 1 EndGreater Than -15°C (5°F)Greater Than -12 VBattery has a net loss less than 0.2 AHFirst level Idle boost request cancelled
Load Shed 1 StartBattery has a net loss of 4 AHRear Defrost, Heated Mirrors, Heated Seats cycled OFF for 20% of their cycle
Load Shed 1 StartLess Than 10.9 VRear Defrost, Heated Mirrors, Heated Seats cycled OFF for 20% of their cycle
Load Shed 1 EndGreater Than 12 VBattery has a net loss of less than 2 AHClear Load Shed 1
Idle Boost 2 StartBattery has a net loss greater than 1.6 AHSecond level Idle boost requested
Idle Boost 2 StartLess Than 10.9 VSecond level Idle boost requested
Idle Boost 2 EndGreater Than 12 VBattery has a net loss less than 0.8 AHSecond level Idle boost request cancelled
Idle Boost 3 StartBattery has a net loss of 10 AHThird level Idle boost requested
Idle Boost 3 StartLess Than 10.9 VThird level Idle boost requested
Idle Boost 3 EndGreater Than 12 VBattery has a net loss of less than 6.0 AHThird level Idle boost request cancelled
Load Shed 2 StartLess Than 10 VBattery has a net loss greater than 12 AHRear Defrost, Heated Mirrors, Heated Seats cycled OFF for 50% of their cycle. The BATTERY SAVER ACTIVE message will be displayed on the DIC
Load Shed 2 StartLess Than 10.9 VRear Defrost, Heated Mirrors, Heated Seats cycled OFF for 50% of their cycle. The BATTERY SAVER ACTIVE message will be displayed on the DIC
Load Shed 2 EndGreater Than 12.6 VBattery has a net loss of less than 10.5 AHClear Load Shed 2
Load Shed 3 StartLess Than 11.9 VBattery has a net loss greater than 20 AHRear Defrost, Heated Mirrors, Heated Seats cycled OFF for 100% of their cycle. The BATTERY SAVER ACTIVE message will be displayed on the DIC
Load Shed 3 EndGreater Than 12.6 VBattery has a net loss of less than 15 AHClear Load Shed 3

Starting System Description and Operation

The starter motors are non-repairable starter motors. They have pole pieces that are arranged around the armature. Both solenoid windings are energized. The pull-in winding circuit is completed to the ground through the starter motor. The windings work together magnetically to pull and hold in the plunger. The plunger moves the shift lever. This action causes the starter drive assembly to rotate on the armature shaft spline as it engages with the flywheel ring gear on the engine. Moving at the same time, the plunger also closes the solenoid switch contacts in the starter solenoid. Full battery voltage is applied directly to the starter motor and it cranks the engine.

As soon as the solenoid switch contacts close, current stops flowing thorough the pull-in winding because battery voltage is applied to both ends of the windings. The hold-in winding remains energized. Its magnetic field is strong enough to hold the plunger, shift lever, starter drive assembly, and solenoid switch contacts in place to continue cranking the engine. When the engine starts, pinion overrun protects the armature from excessive speed until the switch is opened.

When the ignition switch is released from the START position, the START relay opens and battery voltage is removed from the starter solenoid S terminal. Current flows from the motor contacts through both windings to the ground at the end of the hold-in winding. However, the direction of the current flow through the pull-in winding is now opposite the direction of the current flow when the winding was first energized.

The magnetic fields of the pull-in and hold-in windings now oppose one another. This action of the windings, along with the help of the return spring, causes the starter drive assembly to disengage and the solenoid switch contacts to open simultaneously. As soon as the contacts open, the starter circuit is turned off.

Circuit Description (Key Start)

When the ignition switch is placed in the Start position, a discrete signal is supplied to the body control module (BCM) notifying it that the ignition is in the Start position. The BCM then sends a message to the engine control module (ECM) notifying it that CRANK has been requested. The ECM verifies that the transmission is in Park or Neutral. If it is, the ECM then supplies 12 V to the control circuit of the crank relay. When this occurs, battery positive voltage is supplied through the switch side of the crank relay to the S terminal of the starter solenoid.

Special Tools

Illustration Tool Number/Description EL 38758 EL 50074 J 38758 Parasitic Draw Test Switch EL 50313 EL 42000 EL 50076 J 42000 Battery Tester

Scheme 8

Scheme 8: Special Tools
Scheme 8: Special Tools

Scheme 9

Scheme 9
Scheme 9

Scheme 10

Scheme 10
Scheme 10

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Control Module References
• COMPONENT CONNECTOR END VIEWS - INDEX
• Inline Harness Connector End Views
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Diagnostic Repair Verification
• Relay Replacement (Within an Electrical Center)
• Relay Replacement (Attached to Wire Harness)
• Checking Aftermarket Accessories
• Battery Disconnect Warning
• Fastener Caution
• Body Control System Description and Operation
• Power Distribution Schematics
• Diagnostic Trouble Code (DTC) List - Vehicle
• Drive Belt Replacement
• Drive Belt Tensioner Replacement
• Drive Belt Replacement
• Automatic Transmission Controls Schematics
• Automatic Transmission Controls Schematics
• Power Mode Mismatch
• Transmission Internal Mode Switch Logic
• Transmission Internal Mode Switch Logic
• Manual Shift Detent Lever with Shaft Position Switch Assembly Replacement
• Engine Will Not Crank - Crankshaft Will Not Rotate
• Fastener Tightening Specifications (LAF, LEA, or LUK)
• Automatic Transmission Flex Plate Replacement
• Fastener Tightening Specifications
• Engine Control Module Replacement
• Lifting and Jacking the Vehicle
• Secondary Air Injection Pump Replacement
• Starter Generator Replacement
• Air Conditioning Compressor Replacement (V6)
• DTC B1325, B1330, B1517, C0800, P0560, P0562, or P0563
• Special Tools
• Starting System Description and Operation
• Battery Description and Operation
• Fastener Tightening Specifications

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