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Body Control Module Chevrolet Malibu V

Body, Cab Control Systems 4 illustrations ~23986 words

DESCRIPTION

WARNINGDeactivate air bag system before performing any service operation. See AIR BAG RESTRAINT SYSTEM article. DO NOT apply electrical power to any component on steering column without first deactivating air bag system. Air bag may deploy.

Note. The Body Control Module (BCM) may also be referred to as Body Function Controller (BFC).

The Body Function Controller (BFC) performs the following functions: A/C compressor request, A/C cooling fan, exterior and interior lighting control, battery rundown protection, chime, gauge control, instrument cluster indicator control and theft deterrent.

BFC communicates with components using class 2 data line and Serial Peripheral Interface (SPI) data line. BFC acts as an interpreter for data communication between class 2 and SPI data systems. Class 2 data line is used by BFC to communicate with the Electronic Brake Control Module (EBCM) and Powertrain Control Module (PCM). Class 2 serial data uses the peer-to-peer method and message arbitration to manage data line traffic.

SPI is a 3-wire synchronous serial data link through which the BFC controls the instrument cluster. BFC interprets driver warnings sent by control module on class 2 data line, then sends a SPI data message to the instrument cluster. SPI data bus messages include: Fuel gauge position, temperature gauge position, oil pressure, low engine coolant, check oil, volts, ABS, high beam, low fuel, high temperature, washer fluid level low, CRUISE, BRAKE, SERVICE VEHICLE SOON, door ajar, seat belt, theft system, and PRNDL.

Signals that activate the BFC are known as "wake-up" signals. BFC wake-up signals include: door ajar switches, when ignition switch is turned to RUN or ACC position, or inadvertent power.

OPERATION

The PCM and BFC share hardware and software in order to control A/C compressor clutch. The BFC performs the following software functions: Limits low speed compressor operation, prevents clutch slippage, monitors for overpressure or high coolant temperature, determines low ambient pressure and controls compressor clutch.

Battery rundown protection (or battery guard) feature provides protection from excessive battery drain caused by high current loads that are accidentally left on. When ignition is turned off, a time-out period is started. If odometer reads less than 15 miles, time-out period will last for 3 minutes. If odometer reads more than 15 miles, time-out period will last for 20 minutes. When time-out expires, inadvertent power output is turned off.

Each time ignition switch is turned from ACC to RUN position, BFC controls an instrument cluster bulb check for a calibrated amount of time. During this bulb check, instrument cluster will perform a WOW (all gauge indicators are moved at the same time).

When BFC activates an indicator in the instrument cluster, it may also produce a chime. The following chimes are provided: Key-in-ignition, headlights on, unfastened seat belt, turn signal on, parking brake warning, door ajar warning and check gauges.

COMPONENT LOCATIONS

ComponentLocation
Ambient Light SensorTop Of Instrument Panel Trip Pad
Body Function Controller (BFC) (1)Below Right Side Of Instrument Panel
Door Ajar SwitchIn Respective Door
Electronic Brake ControlInside Left Fender Module (EBCM)
Engine Coolant Level SwitchRight Front Corner Of Engine Compartment Attached To Coolant Reservoir
Fuel Tank ModuleUnder Center Rear Of Vehicle
Ignition SwitchLeft Side Of Instrument Panel
Parking Brake SwitchUnder Left Kick Panel Connector
Powertrain Control Module (PCM)Under Left Side Of Instrument Panel Near Steering Column
Remote Control Door Lock Receiver (RFA)Rear Package Shelf
Seat Belt SwitchUnder Driver's Seat
Sensing & Diagnostic Module (SDM)Under Passenger's Seat
Washer Fluid Level SensorInside Left Fender
Wiring Harness Junction Blocks
Left Instrument PanelUnder Left End Of Instrument Panel
Right Instrument PanelUnder Right End Of Instrument Panel
UnderhoodLeft Side Of Engine Compartment
(1) The Body Control Module (BCM) may also be referred to as Body Function Controller (BFC).
(1)The Body Control Module (BCM) may also be referred to as Body Function Controller (BFC).

COMPONENT LOCATIONS

REPROGRAMMING BFC

Note. To reprogram BFC, a Techline Terminal is required.

  1. Connect scan tool. Select SERVICE PROGRAMMING from main menu. After entering vehicle information, choose REQUEST INFO soft key on scan tool. Disconnect scan tool from vehicle.
  2. Connect scan tool to Techline Terminal. Select SERVICE PROGRAMMING SYSTEM. Select TERMINAL TO SCAN TOOL PROGRAMMING method. Select DONE. Follow instructions on communications setup screen.
  3. Select PROGRAM BODY FUNCTION CONTROLLER. Select PROGRAM at SUMMARY screen. Techline Terminal will download information to scan tool. Disconnect scan tool from Techline Terminal.
  4. Connect scan tool to vehicle. Turn ignition switch to RUN position. Select SERVICE PROGRAMMING from MAIN MENU. Follow prompts on vehicle year and type. Press BODY FUNCTION CONTROLLER soft key on scan tool. BFC will be programmed with configuration file stored in scan tool.
  5. Reprogram theft deterrent system. See «ANTI-THEFT SYSTEM»(/chevrolet/malibu/v-1996-2000/remont/door-locks-anti-theft-systems/#anti-theft-system) article. Reprogram PCM using Techline equipment. Verify BFC is operating properly.

HISTORY/INTERMITTENT DTCS

  1. Intermittent failures may be caused by problems with electrical circuit. If a visual inspection does not locate problem, vehicle may be driven with a DVOM attached to suspect circuit. Abnormal voltage or resistance readings when problem occurs indicates problem is within that circuit.
  2. To check for possible loss of DTC memory, disconnect headlight connector and idle engine until SERVICE VEHICLE SOON indicator illuminates. Several DTCs should be set and stored in memory when ignition is turned to OFF position. If DTCs are not set as specified, BFC is faulty.
  3. If SERVICE VEHICLE SOON indicator is illuminated and no DTC is stored, check for an ignition coil shorted to ground and arcing at ignition wires. Also check for poor ground connections at BFC and instrument cluster.
  4. Check for electrical system interference (sharp electrical surge) caused by a faulty relay, PCM-driven solenoid or switch. This problem will normally occur when faulty component is operated.
  5. Check for improper installation of aftermarket electrical equipment (cellular phones, etc.). Ensure Ignition Control Module (ICM) wiring is kept away from generator. Check for open diode in A/C compressor clutch.

MULTIPLE INDICATORS LIGHT CONTINUOUSLY

Check for serial data loss. See WIRING DIAGRAMS .

SCAN TOOL CANNOT COMMUNICATE WITH BFC

Locate and repair serial data loss. See WIRING DIAGRAMS .

PRNDL IS BLANK. ABS, SERVICE VEHICLE SOON & THEFT SYSTEM INDICATORS ON. FUEL & TEMPERATURE GAUGES AT ZERO.

Loss of SPI data bus has occurred. Perform BFC DIAGNOSTIC SYSTEM CHECK under DIAGNOSTIC TESTS. Repair any DTCs that may be set. See DIAGNOSTIC TESTS.

SERVICE VEHICLE SOON INDICATOR DOES NOT LIGHT OR ON CONTINUOUSLY

Using scan tool, check for DTCs. See SELF-DIAGNOSTIC SYSTEM. If any DTCs exist, diagnose and repair as necessary. See procedures in DIAGNOSTIC TESTS . If no DTCs exist and BFC is commanding SERVICE VEHICLE SOON indicator ON, replace BFC. See REMOVAL & INSTALLATION. If no DTCs exist and BFC is commanding SERVICE VEHICLE SOON indicator OFF, replace instrument cluster. See INSTRUMENT PANEL article.

INDICATOR DOES NOT LIGHT

LED indicators are not replaceable. Replace instrument cluster. See INSTRUMENT PANEL article.

BFC HAS BEEN REPLACED, THEFT SYSTEM INDICATOR ON CONTINUOUSLY & ENGINE STARTS

Reprogram PCM to relearn theft system password. See procedures in ANTI-THEFT SYSTEM article.

SPEEDOMETER MALFUNCTIONING

Diagnose Vehicle Speed Sensor (VSS), located on transaxle. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE section

  1. «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l) - 2.4L
  2. «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-31l) - 3.1L

Repair as necessary. If speedometer is still malfunctioning, replace instrument cluster. See INSTRUMENT PANEL article.

TACHOMETER MALFUNCTIONING

  1. Using scan tool, monitor PCM. If ENGINE RPM signal is correct, go to next step. If ENGINE RPM signal is incorrect, see procedures in appropriate TESTS W/CODES article in ENGINE PERFORMANCE section: «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l) - 2.4L «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-31l) - 3.1L
  2. Using scan tool, monitor BFC SPI serial data bus to determine if tachometer is active. If incorrect ENGINE RPM signal is displayed, locate and repair problem in instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article. If correct ENGINE RPM signal is displayed, replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article.

ENGINE COOLANT TEMPERATURE GAUGE MALFUNCTIONING

  1. Using scan tool, monitor PCM. If engine coolant temperature signal is correct, go to next step. If engine coolant temperature signal is incorrect, see appropriate TESTS W/CODES article in ENGINE PERFORMANCE section: «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l) - 2.4L «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-31l) - 3.1L
  2. Using scan tool, monitor BFC SPI serial data bus. If engine coolant temperature signal is correct, replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article. If engine coolant temperature signal is incorrect, perform an instrument cluster WOW. If engine coolant temperature signal is still incorrect, replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) .

FUEL GAUGE MALFUNCTIONING

See DTC P0462, DTC P0463, or any loss of SPI DTCs. Refer to BFC DTC DEFINITIONS under SELF-DIAGNOSTIC SYSTEM. Repair as necessary.

ABS INDICATOR LIGHTS CONTINUOUSLY WITH NO LOSS OF SERIAL DATA

  1. Using scan tool, monitor EBCM. If EBCM is commanding BFC to turn ABS indicator ON, see ANTI-LOCK BRAKES article in BRAKES section. If EBCM is commanding ABS indicator OFF, go to next step.
  2. Using scan tool, monitor BFC SPI serial data bus. If BFC is commanding ABS indicator ON, replace BFC. See REMOVAL & INSTALLATION. If BFC is commanding ABS indicator OFF, replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article.

BRAKE INDICATOR LIGHTS CONTINUOUSLY WITH NO LOSS OF SERIAL DATA, PARKING BRAKE RELEASED & EBCM NOT COMMANDING INDICATOR TO ILLUMINATE

  1. Using scan tool, monitor BFC parking brake input. If parking brake input is OFF, go to next step. If parking brake input is ON, diagnose problem in audible warning system.
  2. Using scan tool, monitor EBCM. If EBCM is BRAKE indicator ON, see ANTI-LOCK BRAKES article in BRAKES section. If EBCM is commanding BRAKE indicator OFF, go to next step.
  3. Using scan tool, monitor BFC SPI serial data bus. If BFC is commanding BRAKE indicator ON, replace BFC. See procedures in «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . If BFC is not commanding BRAKE indicator ON, replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article.

CHECK ENGINE INDICATOR LIGHTS CONTINUOUSLY

See appropriate TESTS W/CODES article in ENGINE PERFORMANCE section.

  1. «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l) - 2.4L
  2. «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-31l) - 3.1L

CHECK OIL INDICATOR LIGHTS CONTINUOUSLY WITH NO LOSS OF SERIAL DATA

  1. Using scan tool, monitor PCM. If PCM is commanding CHECK OIL indicator ON, go to appropriate TESTS W/CODES article in ENGINE PERFORMANCE section: «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l) - 2.4L «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-31l) - 3.1L If PCM is commanding CHECK OIL indicator OFF, go to next step.
  2. Using scan tool, monitor BFC SPI serial data link. If BFC is commanding CHECK OIL indicator ON, replace BFC. See procedures in «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . If BFC is commanding CHECK OIL indicator OFF and indicator is illuminated, replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article.

CRUISE INDICATOR LIGHTS CONTINUOUSLY WITH NO LOSS OF SERIAL DATA

  1. Using scan tool, monitor PCM. If PCM is commanding CRUISE indicator ON, go to appropriate TESTS W/CODES article in ENGINE PERFORMANCE section. If PCM is commanding CRUISE indicator OFF, go to next step. «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l) - 2.4L «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-31l) - 3.1L
  2. Using scan tool, monitor BFC SPI serial data link. If BFC is commanding CRUISE indicator ON, replace BFC. See procedures in «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . If BFC is commanding CRUISE indicator OFF and indicator is illuminated, replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article.

FUEL GAUGE CHECK INDICATOR LIGHT REMAINS ON WHEN GAUGE POINTER IS IN NORMAL RANGE OR FAILS TO LIGHT WHEN GAUGE POINTER IS OUT OF RANGE

Using scan tool, monitor BFC SPI serial data link. If BFC is commanding fuel gauge check indicator ON, replace BFC. See procedures in REMOVAL & INSTALLATION . If BFC is commanding fuel gauge check indicator OFF and indicator is illuminated, replace instrument cluster. See INSTRUMENT PANEL article.

HIGH BEAM INDICATOR MALFUNCTIONING

Diagnose headlight and daytime running light system. See WIRING DIAGRAMS . Repair as necessary. If no problem was found in headlight or daytime running lights system, replace instrument cluster. See INSTRUMENT PANEL article.

ENGINE COOLANT TEMPERATURE GAUGE CHECK INDICATOR LIGHT REMAINS ON WHEN GAUGE POINTER IS IN NORMAL RANGE OR FAILS TO LIGHT WHEN GAUGE POINTER IS OUT OF RANGE

Using scan tool, monitor BFC SPI serial data link. If BFC is commanding engine coolant temperature gauge check indicator ON, replace BFC. See REMOVAL & INSTALLATION . If BFC is commanding engine coolant temperature gauge check indicator OFF and indicator is illuminated, replace instrument cluster. See INSTRUMENT PANEL article.

LEFT OR RIGHT TURN INDICATOR MALFUNCTIONING

See WIRING DIAGRAMS . Repair as necessary.

LOW COOLANT INDICATOR LIGHTS CONTINUOUSLY

  1. Using scan tool, monitor BFC inputs. If low coolant indicator is ON, see «LOW ENGINE COOLANT INDICATOR MALFUNCTIONS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) under DIAGNOSTIC TESTS. If low coolant indicator is not ON, go to next step.
  2. Using scan tool, monitor BFC SPI serial data link. If BFC is commanding low coolant indicator OFF and indicator is illuminated, replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article.

LOW WASH INDICATOR MALFUNCTIONING

  1. Using scan tool, monitor BFC inputs. If LOW WASH indicator is LOW, see «WASHER FLUID LEVEL INDICATOR MALFUNCTIONS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) under DIAGNOSTIC TESTS. If LOW WASH indicator is not LOW, go to next step.
  2. Using scan tool, monitor BFC SPI serial data link. If BFC is commanding LOW WASH indicator OK and indicator is illuminated, replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article.

OIL PRESSURE INDICATOR LIGHTS CONTINUOUSLY WITH NO LOSS OF SERIAL DATA

  1. Using scan tool, monitor PCM. If PCM is commanding oil pressure indicator ON, go to appropriate TESTS W/CODES article in ENGINE PERFORMANCE section: «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l) - 2.4L «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-31l) - 3.1L If PCM is not commanding oil pressure indicator ON, go to next step.
  2. Using scan tool, monitor BFC SPI serial data link. If BFC is commanding oil pressure indicator OFF and indicator is illuminated, replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article.

PRNDL DISPLAY MALFUNCTIONING WITH NO LOSS OF SERIAL DATA

  1. Using scan tool, monitor PCM. If GEAR POSITION matches PRNDL display, go to appropriate TESTS W/CODES article in ENGINE PERFORMANCE section: «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l) - 2.4L «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-31l) - 3.1L If GEAR POSITION does not match PRNDL display, go to next step.
  2. Using scan tool, monitor BFC SPI serial data link. If BFC command does not match TRANSAXLE RANGE reading from PCM, replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . If PRNDL display on instrument cluster does not match GEAR POSITION reading, replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article.

SEAT BELT INDICATOR LIGHTS CONTINUOUSLY WITH NO LOSS OF SERIAL DATA & SEAT BELT BUCKLED

  1. Using scan tool, monitor BFC inputs. If seat belt input is UNBUCKLED, diagnose problem in audible warning system. See «WIRING DIAGRAMS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) . If seat belt input is not UNBUCKLED, go to next step.
  2. Using scan tool, monitor BFC SPI serial data bus. If BFC is commanding seat belt indicator UNBUCKLED, replace BFC. See procedures in «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . If BFC is commanding seat belt indicator BUCKLED, replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article.

THEFT SYSTEM INDICATOR LIGHTS CONTINUOUSLY OR IS MALFUNCTIONING

See ANTI-THEFT SYSTEM article.

VOLTS INDICATOR LIGHTS CONTINUOUSLY WITH NO LOSS OF SERIAL DATA

Check for presence of DTC's B1487, B1488, B1492 or B1493. See BFC DTC DEFINITIONS under SELF-DIAGNOSTIC SYSTEM. Repair as necessary.

AUTOMATIC LIGHT CONTROL DOES NOT FUNCTION

Check for DTC B2575, B2577, B2578, B2585, B2587 or B2588. See BFC DTC DEFINITIONS under SELF-DIAGNOSTIC SYSTEM. Repair as necessary.

PHASE LOOP LOCK INDICATES FAULT

Replace instrument cluster. See INSTRUMENT PANEL article.

A/C DOES NOT FUNCTION

See A/C-HEATER SYSTEM article

SELF-DIAGNOSTIC SYSTEM

Body Function Controller (BFC) is equipped with a self-diagnostic system, which detects system Diagnostic Trouble Codes (DTCs) or abnormalities. When a malfunction occurs, BFC will store a DTC. See BFC DTC DEFINITIONS. Malfunctions are recorded as history/intermittent failures or as current failures. Current DTCs indicate BCM has detected a fault which is currently present. A history DTC is a fault that disappears in the next ignition cycle.

A scan tool can be used to retrieve and clear DTCs. The scan tool also has several features that can be used to help locate an intermittent condition. When scan tool is used for system tests, it will display values actually seen or commanded by various systems (i.e., BFC, PCM, instrument cluster, EBCM or SDM). This will usually include the following types of information

  1. Analog Data Input - Displays analog input seen by system.
  2. Inputs/Outputs - Displays digital values as seen by system, and provides indication of whether input or output has cycled.
  3. Special Functions (Output Controls) - Allows for outputs of system to be set at a desired value (ON or OFF).
  4. Clear Codes - Will erase DTCs for system currently selected (if problem still exists in system, DTC may immediately reset).

BFC DTC DEFINITIONS

Code No.Circuit Affected
B1000Internal BFC Fault Detected
B1001Vehicle Option Configuration Error
B1369(2) Ignition 0 Fault
B1374(3) Ignition 1 Fault (With Engine Running)
B1379(4) Ignition 3 Fault
B1487Generator "L" Terminal Low
B1488Generator "L" Terminal High
B1492Generator "F" Terminal Low
B1493Generator "F" Terminal High
B2532Front Foglight Relay Output Short To Ground/Open
B2533Front Foglight Relay Output Short To Battery
B2558Interior Light Control Output Short To Battery
B2575ALC Headlight System Fault
B2577ALC Headlight Relay Output Short To Ground/Open
B2578ALC Headlight Relay Output Short To Battery
B2585ALC Parking Light System Fault
B2587ALC Parking Light Relay Output Short To Ground/Open
B2588ALC Parking Light Relay Output Short To Battery
B2600DRL Error
B2602DRL Relay Output Short To Ground/Open
B2603DRL Relay Output Short To Battery
B2647Ambient Light Sensor Short To Ground/Open
B2648Ambient Light Sensor Short To Battery
B2947(5) PASSLOCK(R) Power Output Short To Ground
B2948(5) PASSLOCK(R) Power Output Short To Battery
B2957(5) PASSLOCK(R) Signal Data Short To Ground
B2958(5) PASSLOCK(R) Signal Data Open/Short To Battery
B2960(5) PASSLOCK(R) Cylinder Data Incorrect
B2965(6) Key-In-Ignition Fault
B3031(5) BFC In Learn Mode (Current Code Only)
B3033(5) Tamper Mode Enabled
P0462Fuel Level Sensor Signal Short To Ground
P0463Fuel Level Sensor Signal Open/Short To Battery
U1000Loss Of Class 2 Serial Data Fault (General)
U1016PCM Class 2 Serial Data State Of Health Fault
U1040EBCM Class 2 Serial Data State Of Health Fault
U2000Invalid BFC Transmitted SPI Data
U2001Invalid Instrument Cluster Transmitted SPI Data
U2002SPI Data Input Low
U2003SPI Data Input High
U2004SPI Data Output Low
U2005SPI Data Output High
U2006SPI Clock Output Low
U2007SPI Clock Output High
(1) Perform appropriate test under DIAGNOSTIC TESTS . (2) This code sets when Ignition 0 input is not active and Ignition 1 is active for 20 seconds. (3) This code sets when Ignition 1 input is not active, Ignition 3 is active for 20 seconds, and engine is running for 20 seconds. (4) This code sets when Ignition 3 input is not active and Ignition 1 is active for 20 seconds. (5) See ANTI-THEFT SYSTEM article. (6) This code sets when key-in input is not active and Ignition 0 is active for 20 seconds.
(1)Perform appropriate test under DIAGNOSTIC TESTS .
(2)This code sets when Ignition 0 input is not active and Ignition 1 is active for 20 seconds.
(3)This code sets when Ignition 1 input is not active, Ignition 3 is active for 20 seconds, and engine is running for 20 seconds.
(4)This code sets when Ignition 3 input is not active and Ignition 1 is active for 20 seconds.
(5)See ANTI-THEFT SYSTEM article.
(6)This code sets when key-in input is not active and Ignition 0 is active for 20 seconds.

BFC DTC DEFINITIONS (1)

DIAGNOSTIC TESTS

Note. DO NOT replace BFC unless a DTC remains current after all DTC repairs have been performed. DO NOT replace BFC if only history DTCs are set.

Note. To identify and locate components, see COMPONENT LOCATIONS . For wiring and connector terminal identification, see WIRING DIAGRAMS .

BFC DIAGNOSTIC SYSTEM CHECK

  1. Reinstall any components that have been removed. Cycle ignition switch from OFF to RUN position, engine off. Connect scan tool. Attempt to establish communication with BFC. If scan tool displays data, go to step 3). If scan tool does not display data, go to next step.
  2. Diagnose and repair problem in DLC. See «WIRING DIAGRAMS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) . Attempt to establish communication with BFC. If scan tool displays data, go to next step.
  3. Using scan tool, select BODY FUNCTIONS. Check for BFC DTCs. If any DTC exists, go to «BFC DTC DEFINITIONS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) under SELF-DIAGNOSTIC SYSTEM. If no DTCs exist, go to next step.
  4. Disconnect scan tool. Cycle ignition switch from OFF to RUN position. If all indicators turned on and off, go to step 6). If all indicators did not turn on and off, go to next step.
  5. Start engine. If any indicator stays on or flashes, go to «TROUBLE SHOOTING»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) . If no indicator stays on or flashes, go to next step.
  6. Check for DTCs. If any history DTC exists, go to next step. If no DTCs exist, system is operating properly.
  7. Using scan tool, retrieve freeze frame and failure records information. Duplicate conditions under which DTC was set. If DTC resets as current, go to «BFC DTC DEFINITIONS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) under SELF-DIAGNOSTIC SYSTEM. If DTC does not reset, system is operating properly.

This test will determine if instrument cluster is reading information from a class 2 component, and if scan tool is able to turn instrument cluster indicators off or on (this does not apply to SIR, CHECK ENGINE or turn signal indicators).

Testing

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Using scan tool, monitor input data from class 2 serial data component or other BFC inputs for indicator that is illuminated. If class 2 component is commanding indicator ON, locate and repair problem in that component. If class 2 component is not commanding indicator ON, go to next step.
  3. Using scan tool, determine if BFC is commanding indicator(s) ON. If scan tool cannot toggle (or WOW) instrument cluster using BFC, go to next step. If scan tool can toggle (or WOW) instrument cluster using BFC, go to step 5).
  4. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) .
  5. Replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article.

This test will determine if instrument cluster is reading information from a class 2 component, and if scan tool is able to WOW (turn on all indicators and move all gauges simultaneously) instrument cluster.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Using scan tool, monitor input data from class 2 serial data component for indicator that will not illuminate. If class 2 component is commanding indicator OFF, locate and repair problem in that component. If class 2 component is not commanding indicator OFF, go to next step.
  3. Using scan tool, command BFC to WOW instrument cluster to turn indicator(s) ON. If scan tool cannot toggle (or WOW) instrument cluster using BFC, go to next step. If scan tool can toggle (or WOW) instrument cluster using BFC, go to step 5).
  4. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) .
  5. Replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article.

Low coolant switch closes when engine coolant level is low, and sends a discrete input to BFC. When ignition switch is in RUN position and coolant level input is low for at least 10 seconds, low engine coolant indicator will illuminate. If low coolant switch input is inactive for at least 2 seconds, low engine coolant indicator will turn off. This is a distributed function between instrument cluster and BFC.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect engine coolant level switch connector. Using scan tool, read BFC inputs. If low coolant level reads OFF, go to next step. If low coolant level does not read OFF, go to step 4).
  3. Replace engine coolant level switch.
  4. Back out BFC Pink 24-pin connector C3, terminal B6 (Yellow/Black wire). Using scan tool, read BFC inputs. If low coolant level reads OFF, go to next step. If low coolant level does not read OFF, go to step 11).
  5. Check for a poor connection at BFC connector C3, terminal B6 (Yellow/Black wire). If a poor connection exists, go to next step. If connection is okay, go to step 7).
  6. Repair poor connection at BFC connector C3, terminal B6 (Yellow/Black wire).
  7. Check for a poor connection at Yellow/Black wire terminal of engine coolant level switch. If a poor connection exists, go to next step. If connection is okay, go to step 9).
  8. Repair poor connection at Yellow/Black wire terminal of engine coolant level switch.
  9. Using DVOM, check resistance between engine coolant level switch harness connector "A" (Yellow/Black wire) and ground. If resistance is less than infinite, go to next step. If resistance is not less than infinite, go to step 11).
  10. Repair short to ground in Yellow/Black wire between BFC and engine coolant level switch.
  11. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) .

Low washer level switch closes when washer fluid level is low, and sends a discrete input to BFC. When washer fluid level input is low for at least 30 seconds, BFC will send a SPI serial data message to instrument cluster to illuminate low washer fluid level indicator. If low washer fluid level switch input is inactive for at least 30 seconds, low washer fluid level indicator will turn off.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect washer fluid level switch connector. Using scan tool, read BFC inputs. If washer fluid level reads OK, go to next step. If washer fluid level does not read OK, go to step 4).
  3. Replace washer fluid level switch.
  4. Back out BFC Pink 24-pin connector C3, terminal A6 (Black/White wire). Using scan tool, read BFC inputs. If washer fluid level reads OK, go to next step. If washer fluid level does not read OK, go to step 7).
  5. Using DVOM, check resistance between washer fluid level switch harness connector "A" (Black/White wire) and ground. If resistance is less than infinite, go to next step. If resistance is not less than infinite, go to step 7).
  6. Repair short to ground in Black/White wire between BFC and washer fluid level switch.
  7. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) .

DTC B1000 will set when a EEPROM checksum error exists. When DTC B1000 is set, SERVICE VEHICLE SOON indicator will illuminate. DTC B1000 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B1001 will set when vehicle option configuration is not set when BFC is programmed. When DTC B1001 is set, SERVICE VEHICLE SOON indicator will illuminate. DTC B1001 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check)
  2. Reprogram BFC. See REPROGRAMMING BFC. Perform procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

Circuit No. 1600 (Purple wire) provides input from ignition switch to BFC and instrument cluster. DTC B1369 will set when Ignition 0 is not active, and Ignition 1 is active for 20 seconds. See WIRING DIAGRAMS . DTC B1369 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

Diagnostic Aids

If fuel gauge reads empty at all times, BFC circuits or BFC is faulty. If Ignition 0 does not exist, instrument cluster will not function. If only history DTC B1369 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect BFC Gray 16-pin connector C1, terminal A8 (Purple wire). Turn ignition switch to ACC or RUN position. Using DVOM, check voltage between BFC harness connector C1, terminal A8 (Purple wire) and ground. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 6).
  3. Check for poor connection at BFC connector C1, terminal A8 (Purple wire). If a poor connection exists, go to next step. If connection is okay, go to step 5).
  4. Repair poor connection at BFC connector C1, terminal A8 (Purple wire). Go to step 11).
  5. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 11).
  6. Disconnect left I/P wiring harness junction block Brown 68-pin connector C1, terminal C9 (Purple wire). Using DVOM, check resistance between BFC harness connector C1, terminal A8 (Purple wire) and left I/P wiring harness junction block harness connector C1, terminal C9 (Purple wire). If resistance is 0-2 ohms, go to step 8). If resistance is not 0-2 ohms, go to next step.
  7. Repair open in Purple wire between BFC connector C1 and left I/P wiring harness junction block connector C1. Go to step 11).
  8. Check for a poor connection at left I/P wiring harness junction block connector C1, terminal C9 (Purple wire). If a poor connection exists, go to next step. If connection is okay, go to step 10).
  9. Repair poor connection at left I/P wiring harness junction block connector C1, terminal C9 (Purple wire). Go to step 11).
  10. Replace left I/P wiring harness junction block connector. Go to next step.
  11. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

Circuit No. 439 (Pink wire) provides input from ignition switch to BFC. DTC B1374 will set when Ignition 1 is not active, and Ignition 3 is active for 20 seconds. See WIRING DIAGRAMS . DTC B1374 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If Ignition 1 is not active, EBCM will not communicate with scan tool. If only history DTC B1374 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect BFC Gray 24-pin connector C2, terminal B9 (Pink wire). Using DVOM, check voltage between BFC harness connector C2, terminal B9 (Pink wire) and ground. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 6).
  3. Check for poor connection at BFC connector C2, terminal B9 (Pink wire). If a poor connection exists, go to next step. If connection is okay, go to step 5).
  4. Repair poor connection at BFC connector C2, terminal B9 (Pink wire). Go to step 11).
  5. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 11).
  6. Disconnect underhood wiring harness junction block Brown 68-pin Brown connector C3, terminal C4 (Pink wire). Using DVOM, check resistance between BFC harness connector C2, terminal B9 (Pink wire) and underhood wiring harness junction block harness connector C3, terminal C4 (Pink wire). If resistance is 0-2 ohms, go to step 8). If resistance is not 0-2 ohms, go to next step.
  7. Repair open in Pink wire between BFC connector C2 and underhood wiring harness junction block connector C3. Perform procedures in step 11).
  8. Check for a poor connection at underhood wiring harness junction block connector C3, terminal C4 (Pink wire). If a poor connection exists, go to next step. If connection is okay, go to step 10).
  9. Repair poor connection at underhood wiring harness junction block connector C3, terminal C4 (Pink wire). Go to step 11).
  10. Replace underhood wiring harness junction block connector. Go to next step.
  11. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

Circuit No. 341 (Brown wire) provides input from ignition switch to BFC. DTC B1379 will set when Ignition 3 is not active, and Ignition 1 is active for 20 seconds. See WIRING DIAGRAMS . DTC B1379 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only BFC is affected, low beams will not function when BFC is in Automatic Light Control (ALC) mode. If only history DTC B1379 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Turn ignition switch to RUN position. Disconnect BFC Gray 16-pin connector C1, terminal B8 (Brown wire). Using DVOM, check voltage between BFC harness connector C1, terminal B8 (Brown wire) and ground. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 6).
  3. Check for poor connection at BFC connector C1, terminal B8 (Brown wire). If a poor connection exists, go to next step. If connection is okay, go to step 5).
  4. Repair poor connection at BFC connector C1, terminal B8 (Brown wire). Go to step 11).
  5. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 11).
  6. Disconnect right I/P wiring junction block Natural 68-pin connector C1, terminal C4 (Brown wire). Using DVOM, check resistance between BFC harness connector C1, terminal B8 (Brown wire) and right I/P wiring harness junction block connector C1, terminal C4 (Brown wire). If resistance is 0-2 ohms, go to step 8). If resistance is not 0-2 ohms, go to next step.
  7. Repair open in Brown wire between BFC connector C1 and right I/P wiring harness junction block connector C1. Go to step 11).
  8. Check for a poor connection at right I/P wiring harness junction block connector C1, terminal C4 (Brown wire). If a poor connection exists, go to next step. If connection is okay, go to step 10).
  9. Repair poor connection at right I/P wiring harness junction block connector C1, terminal C4 (Brown wire). Go to step 11).
  10. Replace right I/P wiring harness junction block connector. Go to next step.
  11. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B1487 will set when a fault exists that is causing generator "L" terminal to read LOW continuously while engine is running. This DTC will be set when engine is running, PCM sends an "engine is running" class 2 data message, and PCM does not send an "L" terminal high" class 2 data message for 30 seconds after vehicle has started. When DTC B1487 is set, VOLTS indicator will illuminate. DTC B1487 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B1487 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Run engine for more than one minute. Using DVOM, check voltage by backprobing between generator harness connector terminal "B" (Red wire) and ground. If battery voltage exists, go to step 9). If battery voltage does not exist, go to next step.
  3. Disconnect generator connector. On 2.4L, disconnect PCM Blue 80-pin connector C1. On 3.1L, disconnect PCM Clear 80-pin connector C2. On all models, use DVOM to check resistance between generator harness connector terminal "B" (Red wire) and ground. If resistance is infinite, go to next step. If resistance is not infinite, go to step 7).
  4. Reconnect all connectors and components. Run engine for more than one minute. Using DVOM, check voltage by backprobing between generator harness connector terminal "B" (Red wire) and ground. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 6).
  5. Using scan tool, read PCM "L" terminal input. If "L" terminal input is high, go to step 9). If "L" terminal is not high, go to step 8).
  6. Replace generator. See «GENERATOR & REGULATOR»(/chevrolet/malibu/v-1996-2000/remont/charging-system/#charging-system) article in ELECTRICAL. Go to step 9).
  7. Repair short to ground in Red wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 9).
  8. Replace PCM. See «REMOVE/INSTALL/OVERHAUL»(/chevrolet/malibu/v-1996-2000/remont/removal-installation/#how-to-overhaul-24l-the-engine-controls-removal-installation) article in ENGINE PERFORMANCE section. Go to next step.
  9. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B1488 will set when a fault exists that is causing generator "L" terminal to read HIGH continuously. This DTC will be set when Ignition 1 is active, engine is off and PCM is sending an ""L" terminal high" class 2 data message for 30 seconds. When DTC B1488 is set, VOLTS indicator will illuminate. DTC B1487 can be cleared using scan tool.

With engine off, check for a short to battery in circuit No. 225 (Red wire) between PCM and generator. If only history DTC B1488 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Turn ignition switch to RUN position, with engine off. Using DVOM, check voltage by backprobing between generator harness connector terminal "B" (Red wire) and ground. If about zero volts exists, go to step 5). If about zero volts does not exist, go to next step.
  3. Disconnect generator connector. On 2.4L, disconnect PCM Blue 80-pin connector C1. On 3.1L, disconnect PCM Clear 80-pin connector C2. On 2.4L, use DVOM to check resistance between PCM harness connector C1, terminal No. 74 (Red wire) and generator harness connector terminal "B" (Red wire). On 3.1L, use DVOM to check resistance between PCM harness connector C2, terminal No. 35 (Red wire) and generator connector terminal "B" (Red wire). If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 7).
  4. Reconnect all connectors and components. Turn ignition switch to RUN position, with engine off. On 2.4L, use DVOM to check voltage by backprobing between PCM harness connector C1, terminal No. 74 (Red wire) and ground. On 3.1L, use DVOM to check voltage by backprobing between PCM harness connector C2, terminal No. 35 (Red wire) and ground. If battery voltage exists, go to step 6). If battery voltage does not exist, go to step 8).
  5. Using scan tool, read PCM "L" terminal status. If "L" terminal input is low, go to step 9). If "L" terminal is not low, go to step 8).
  6. Replace generator. See «GENERATOR & REGULATOR»(/chevrolet/malibu/v-1996-2000/remont/charging-system/#charging-system) article in ELECTRICAL. Go to step 9).
  7. Repair open in Red wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 9).
  8. Replace PCM. See «REMOVE/INSTALL/OVERHAUL»(/chevrolet/malibu/v-1996-2000/remont/removal-installation/#how-to-overhaul-24l-the-engine-controls-removal-installation) article in ENGINE PERFORMANCE section. Go to next step.
  9. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B1492 will set when a fault exists that is causing generator PWM to read LOW continuously. This DTC will be set when PCM is sending "engine is running" and "generator PWM is less than 1.96 percent" class 2 data messages, field terminal present calibration is enabled in PCM, and engine is running at about 3000 RPM for 30 seconds.

When DTC B1492 is set, VOLTS indicator will illuminate. DTC B1492 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

When engine is running, generator "F" terminal should be low. If only history DTC B1492 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. On 2.4L, disconnect PCM Blue 80-pin connector C1, terminal No. 53 (Gray wire). On 3.1L, disconnect PCM Clear 80-pin connector C2, terminal No. 62 (Gray wire). Disconnect generator connector. On 2.4L, use DVOM to check resistance between PCM harness connector C1, terminal No. 53 (Gray wire) and ground. On 3.1L, use DVOM to check resistance between PCM harness connector C2, terminal No. 62 (Gray wire) and ground. If resistance is infinite, go to step 4). If resistance is not infinite, go to next step.
  3. Repair short to ground in Gray wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 10).
  4. On 2.4L, use DVOM to check resistance between PCM harness connector C1, terminal No. 53 (Gray wire) and generator harness connector terminal "C" (Gray wire). On 3.1L, use DVOM to check resistance between PCM harness connector C2, terminal No. 62 (Gray wire) and generator harness connector terminal "C" (Gray wire). If resistance is 0-2 ohms, go to step 6). If resistance is not 0-2 ohms, go to next step.
  5. Repair open in Gray wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 10).
  6. Connect a fused jumper wire between generator terminals "C" (Gray wire) and "D" (Orange wire). Start engine. Using scan tool, read generator PWM. If scan tool displays greater than 50 percent, go to next step. If scan tool does not display greater than 50 percent, go to step 8).
  7. Start engine. Repeatedly reconnect and disconnect generator connector. Using scan tool, read PCM generator PWM status. If PCM generator PWM oscillates, go to step 10). If PCM generator PWM does not oscillate, go to step 9).
  8. Replace PCM. See «REMOVE/INSTALL/OVERHAUL»(/chevrolet/malibu/v-1996-2000/remont/removal-installation/#how-to-overhaul-24l-the-engine-controls-removal-installation) article in ENGINE PERFORMANCE section. Go to step 10).
  9. Replace generator. See «GENERATOR & REGULATOR»(/chevrolet/malibu/v-1996-2000/remont/charging-system/#charging-system) article in ELECTRICAL section. Go to next step.
  10. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B1493 will set when a fault exists that is causing generator "F" terminal to read HIGH continuously. This DTC will be set when engine is running, and PCM is sending "engine RPM is zero" and "generator PWM is equal to or greater than 64 percent duty cycle" class 2 data messages for 30 seconds. When DTC B1493 is set, VOLTS indicator will illuminate. DTC B1493 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B1493 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Turn ignition switch to RUN position, with engine off. Disconnect generator connector. Using scan tool, read generator PWM. If scan tool displays zero percent, go to next step. If scan tool does not display zero percent, go to step 5).
  3. Reconnect generator connector. Start engine. Using scan tool, read generator PWM from PCM. If scan tool displays greater than 50 percent, go to next step. If scan tool does not display greater than 50 percent, go to step 5).
  4. Replace generator. See «GENERATOR & REGULATOR»(/chevrolet/malibu/v-1996-2000/remont/charging-system/#charging-system) article in ELECTRICAL section. Go to next step.
  5. Disconnect generator connector. On 2.4L, disconnect PCM Blue 80-pin connector C1. On 3.1L, disconnect PCM Clear 80-pin connector C2. On all models, use DVOM to check voltage at generator terminal "C" (Gray wire). If reading is zero volts, go to step 7). If reading is not zero volts, go to next step.
  6. Repair short to battery in Gray wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 8).
  7. Replace PCM. See «REMOVE/INSTALL/OVERHAUL»(/chevrolet/malibu/v-1996-2000/remont/removal-installation/#how-to-overhaul-24l-the-engine-controls-removal-installation) article in ENGINE PERFORMANCE section. Go to next step.
  8. Clear DTCs. Perform BFC DIAGNOSTIC SYSTEM CHECK.

DTC B2532: FRONT FOGLIGHT RELAY OUTPUT SHORT TO GROUND/OPEN

Note. To identify relay wiring colors, see appropriate wiring diagram in WIRING DIAGRAMS .

BFC uses circuit No. 1317 (Dark Green/White wire) to ground front foglight relay. DTC B2532 will set when Ignition 1 is active and front foglight switch is not active. DTC B2532 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

Foglights will only illuminate when parking lights are on and foglight switch is actuated. If only history DTC B2532 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove front foglight relay from right I/P wiring harness junction block. Replace foglight relay with a known-good relay. Using scan tool, enable front foglight relay. If front foglight operates properly, go to step 10). If front foglight does not operate properly, go to next step.
  3. Reinstall original foglight relay. Back out right I/P wiring harness junction block Natural 68-pin connector C1, terminal F3 (Dark Green/White wire). Using DVOM, check voltage between right I/P wiring harness junction block connector C1, terminal F3 (Dark Green/White wire) and ground. If battery voltage exists, go to step 5). If battery voltage does not exist, go to next step.
  4. Replace right I/P wiring harness junction block. Go to step 10).
  5. Disconnect BFC Gray 16-pin connector C1, terminal A2 (Dark Green/White wire). Using DVOM, check resistance between BFC connector C1, terminal A2 (Dark Green/White wire) and ground. If resistance is infinite, go to step 7). If resistance is not infinite, go to next step.
  6. Repair short to ground in Dark Green/White wire between BFC connector C1 and right I/P wiring harness junction block connector C1. Go to step 10).
  7. Using DVOM, check resistance between BFC connector C1, terminal A2 (Dark Green/White wire) and right I/P wiring harness junction block connector C1, terminal F3 (Dark Green/White wire). If resistance is 0-2 ohms, go to step 9). If resistance is not 0-2 ohms, go to next step.
  8. Repair open in Dark Green/White wire between BFC connector C1 and right I/P wiring harness junction block connector C1. Go to step 10).
  9. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  10. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

BFC uses circuit No. 1317 (Dark Green/White wire) to ground front foglight relay. DTC B2533 will set when parking lights are commanded on (manually or using ALC function), BFC enables front foglight option, Ignition 1 is active and front foglight relay output is on. When DTC B2533 is set, front foglight will turn off. DTC B2533 can be cleared when fault state is exited when status of front foglight returns to OFF. DTC B2533 can also be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2533 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove front foglight relay from right I/P wiring harness junction block. Replace foglight relay with a known-good relay. Using scan tool, enable front foglight relay. If front foglight operates properly, go to step 8). If front foglight does not operate properly, go to next step.
  3. Remove foglight relay. Back out right I/P wiring harness junction block Natural 68-pin connector C1, terminal F3 (Dark Green/White wire). Using DVOM, check voltage between right I/P wiring harness junction block connector C1, terminal F3 (Dark Green/White wire) and ground. If reading is zero volts, go to step 5). If reading is not zero volts, go to next step.
  4. Replace right I/P wiring harness junction block. Go to step 8).
  5. Disconnect BFC Gray 16-pin connector C1, terminal A2 (Dark Green/White wire). Using DVOM, check voltage between right I/P wiring harness junction block connector C1, terminal F3 (Dark Green/White wire) and ground. If reading is zero volts, go to next step. If reading is not zero volts, go to step 7).
  6. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 8).
  7. Repair short to battery in Dark Green/White wire between BFC connector C1 and right I/P wiring harness junction block connector C1. Go to next step.
  8. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

BFC uses circuit No. 156 (White wire) to ground interior lights. DTC B2558 will set when interior light relay is on (but not in theater or step dim lighting modes) and interior light feedback from circuit No. 156 (White wire) does not exist for .5 second. When DTC B2558 is set, interior light relay will turn off. DTC B2558 can be cleared when fault state is exited when status of interior lights returns to OFF. DTC B2558 can also be cleared using scan tool or when fault conditions no longer exist.

If only history DTC B2558 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect BFC Pink 24-pin connector C3. Remove left and right courtesy lights. Turn dome switch to OFF position. Using DVOM, check voltage between BFC harness connector C3, terminal A11 (White wire) and ground. If zero volts exists, go to step 10). If zero volts does not exist, go to next step.
  3. Disconnect left I/P wiring harness junction block Brown 68-pin connector C1. Disconnect left I/P wiring harness junction block Gray 30-pin connector C2. Disconnect left I/P wiring harness junction block Black 30-pin connector C3. Using DVOM, check voltage between BFC harness connector C3, terminal A11 (White wire) and ground. If zero volts exists, go to step 5). If zero volts does not exist, go to next step.
  4. Repair short to battery in White wire between BFC connector C3 and left I/P wiring harness junction block connector C1. Go to step 11).
  5. Using DVOM, check voltage between left I/P wiring harness junction block Gray 30-pin harness connector C2, terminal C3 (White wire) and ground. If zero volts exists, go to step 7). If zero volts does not exist, go to next step.
  6. Repair short to battery in White wire between left I/P wiring harness junction block connector C2 and left and right courtesy lights. Go to step 11).
  7. Using DVOM, check voltage between left I/P wiring harness junction block Black 30-pin harness connector C3, terminal C10 (White wire) and ground. If zero volts exists, go to step 9). If zero volts does not exist, go to next step.
  8. Repair short to battery in White wire between left I/P wiring harness junction block connector C3 and dome light. Go to step 11).
  9. Replace left I/P wiring harness junction block. Go to step 11).
  10. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  11. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

BFC uses circuit No. 1970 (Pink/White wire) to ground ALC relay coil. DTC B2575 indicates that headlights were not on when ALC relay output was on. DTC B2575 will set when ALC option is enabled and Ignition 1 is active, ALC headlight output is active, high beams are not on (may be off or in DRL mode) and low beams are off for 5 seconds. When DTC B2575 is set, SERVICE VEHICLE SOON indicator will illuminate. DTC B2575 can be cleared when BFC reads proper headlight voltage, using scan tool or when fault conditions no longer exist.

  1. Turn ignition switch to RUN position. Cover ambient light sensor for 30 seconds. Low beams should illuminate. If low beams do not illuminate, see «WIRING DIAGRAMS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) .
  2. Turn ignition switch to RUN position. Turn high beams on. Cover ambient light sensor for 30 seconds. High beams should illuminate. If high beams do not illuminate, see «WIRING DIAGRAMS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) .
  3. If only history DTC B2575 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.
  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. If no other ALC DTCs exist, go to next step. If any other ALC DTCs exist, repair those DTCs first.
  3. Turn low beam headlights on. If both low beam headlights illuminate, go to next step. If both low beam headlights do not illuminate, go to step 7).
  4. Using scan tool, read BFC INPUT for LOW BEAM/DRL FEEDBACK. If scan tool displays DRL ON, go to next step. If scan tool does not display DRL ON, go to step 7).
  5. Turn high beam headlights on. If both high beam headlights illuminate, go to next step. If both high beam headlights do not illuminate, go to step 7).
  6. Using scan tool, read BFC INPUT for HIGH BEAM FEEDBACK. If scan tool displays HIGH BEAMS ON, go to step 10). If scan tool does not display HIGH BEAMS ON, go to next step.
  7. Locate problem in headlight and DRL system. See «WIRING DIAGRAMS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) . Repair as necessary. If repair is complete, go to step 11). If repair is not complete, go to next step.
  8. Remove DRL relay from underhood wiring harness junction block. Replace DRL relay with a known-good relay. Using scan tool, enable DRL relay. If automatic lighting control operates properly, go to step 11). If automatic light control does not operate properly, go to next step.
  9. Remove ALC headlight relay from underhood wiring harness junction block. Replace ALC headlight relay with a known-good relay. Using scan tool, enable ALC headlight relay. If automatic lighting control operates properly, go to step 11). If automatic light control does not operate properly, go to next step.
  10. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  11. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2577: ALC HEADLIGHT RELAY OUTPUT SHORT TO GROUND/OPEN

Note. To identify relay wiring colors, see WIRING DIAGRAMS .

DTC B2577 indicates that ALC headlight relay output is shorted to ground or open. DTC B2577 will set when ambient light sensor indicates bright conditions, ALC option is enabled and Ignition 1 is active, engine is not being cranked ("Ignition 1 active, Ignition 3 inactive and engine not running" class 2 data message), ALC headlight output is not active and ALC headlight feedback exists for 5 seconds.

When DTC B2577 is set, SERVICE VEHICLE SOON indicator will illuminate. DTC B2577 can be cleared when BFC reads proper headlight voltage or using scan tool. History DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2577 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove ALC headlight relay from underhood wiring harness junction block. Replace ALC headlight relay with a known-good relay. Using scan tool, enable ALC headlight relay. If automatic lighting control operates properly, go to step 10). If automatic light control does not operate properly, go to next step.
  3. Reconnect ALC headlight relay. Back out underhood wiring harness junction block Brown 68-pin Brown connector C3, terminal C11 (Pink/White wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal C11 (Pink/White wire) and ground. If battery voltage exists, go to step 5). If battery voltage does not exist, go to next step.
  4. Replace underhood wiring harness junction block. Go to step 10).
  5. Disconnect BFC Gray 16-pin connector C1, terminal A1 (Pink/White wire). Using DVOM, check resistance between BFC harness connector C1, terminal A1 (Pink/White wire) and ground. If resistance is infinite, go to step 7). If resistance is not infinite, go to next step.
  6. Repair short to ground in Pink/White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  7. Using DVOM, check resistance between BFC harness connector C1, terminal A1 (Pink/White wire) and underhood wiring harness junction block harness connector C3, terminal C11 (Pink/White wire). If resistance is 0-2 ohms, go to step 9). If resistance is not 0-2 ohms, go to next step.
  8. Repair open in Pink/White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  9. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  10. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2578 indicates that ALC headlight relay output is shorted to battery. DTC B2578 will set when ambient light sensor indicates bright conditions, ALC option is enabled, ALC headlight output is active and ALC headlight feedback does not exist for one second.

When DTC B2578 is set, ALC headlight relay will turn off and SERVICE VEHICLE SOON indicator will illuminate. DTC B2578 can be cleared when fault state is exited when status of ALC headlights returns to OFF. DTC B2578 can also be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2578 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove ALC headlight relay from underhood wiring harness junction block. Replace ALC headlight relay with a known-good relay. Using scan tool, enable ALC headlight relay. If ALC headlight relay activates, go to step 8). If ALC headlight relay does not activate, go to next step.
  3. Remove ALC headlight relay from underhood wiring harness junction block. Back out underhood wiring harness junction block Brown 68-pin connector C3, terminal C11 (Pink/White wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal C11 (Pink/White wire) and ground. If reading is zero volts, go to step 5). If reading is not zero volts, go to next step.
  4. Replace underhood wiring harness junction block. Go to step 8).
  5. Disconnect BFC Gray 16-pin connector C1, terminal A1 (Pink/White wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal C11 (Pink/White wire) and ground. If reading is zero volts, go to next step. If reading is not zero volts, go to step 7).
  6. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 8).
  7. Repair short to battery in Pink/White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to next step.
  8. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2585 indicates that parking lights were not on when ALC headlight relay output is on. DTC B2585 will set when ALC option is enabled and Ignition 1 is active, ALC parking light output is active, and parking lights' active discrete input is not active for 5 seconds.

When DTC B2585 is set, SERVICE VEHICLE SOON indicator will illuminate. DTC B2585 can be cleared when BFC reads proper parking light voltage. DTC B2578 can also be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If battery voltage exists at BFC parking relay output, check ALC parking light relay and circuits. Check multifunction switch. See STEERING COLUMN SWITCHES article WIRING DIAGRAMS. If only history DTC B2585 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. If no other ALC DTCs exist, go to next step. If any other ALC DTCs exist, repair those DTCs first.
  3. Turn parking lights on. If all parking lights illuminate, go to next step. If all parking lights do not illuminate, go to step 5).
  4. Toggle parking lights on and off. Using scan tool, read BFC INPUT for PARK LAMP INPUT. If scan tool display toggles, go to step 12). If scan tool display does not toggle, go to next step.
  5. If scan tool displays INACTIVE while parking lights are toggled on and off, go to next step. If scan tool does not display INACTIVE while parking lights are toggled on and off, go to step 7).
  6. Locate and repair problem in audible warning system. Go to step 12).
  7. Disconnect right I/P wiring harness junction block Gray 30-pin connector C2, terminal C10 (Brown wire). Disconnect BFC Gray 24-pin connector C2, terminal B8 (Brown wire). Using DVOM, check resistance between right I/P wiring harness junction block harness connector C2, terminal C10 (Brown wire) and BFC harness connector C2, terminal B8 (Brown wire). If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 9).
  8. Using DVOM, check resistance between right I/P wiring harness junction block harness connector C2, terminal C10 (Brown wire) and ground. If resistance is infinite, go to step 11). If resistance is not infinite, go to step 10).
  9. Repair open in Brown wire between BFC connector C2 and right I/P wiring harness junction block connector C2. Go to step 12).
  10. Repair short to ground in Brown wire between BFC connector C2 and right I/P wiring harness junction block connector C2. Go to step 12).
  11. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  12. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2587: ALC PARKING LIGHT RELAY OUTPUT SHORT TO GROUND/OPEN

Note. To identify relay wiring colors, see WIRING DIAGRAMS .

DTC B2587 indicates that ALC parking light relay output is shorted to ground or open. DTC B2587 will set when ALC option is enabled and Ignition 1 is active, ALC parking light output is not active, and ALC parking light feedback exists for 5 seconds.

When DTC B2587 is set, SERVICE VEHICLE SOON indicator will illuminate. DTC B2587 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2587 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove ALC parking light relay from underhood wiring harness junction block. Replace ALC parking light relay with a known-good relay. Using scan tool, enable ALC parking light relay. If ALC parking light relay operates properly, go to step 10). If ALC parking light relay does not operate properly, go to next step.
  3. Ensure ALC parking light relay is installed in underhood wiring harness junction block. Back out underhood wiring harness junction block Brown 68-pin connector C3, terminal B8 (White wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B8 (White wire) and ground. If battery voltage exists, go to step 5). If battery voltage does not exist, go to next step.
  4. Replace underhood wiring harness junction block. Go to step 10).
  5. Disconnect BFC Gray 16-pin connector C1, terminal B1 (White wire). Using DVOM, check resistance between BFC harness connector C1, terminal B1 (White wire) and ground. If resistance is infinite, go to step 7). If resistance is not infinite, go to next step.
  6. Repair short to ground in White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  7. Using DVOM, check resistance between BFC harness connector C1, terminal B1 (White wire) and underhood wiring harness junction block connector C3, terminal B8 (White wire). If resistance is 0-2 ohms, go to step 9). If resistance is not 0-2 ohms, go to next step.
  8. Repair open in White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  9. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  10. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2588: ALC PARKING LIGHT RELAY OUTPUT SHORT TO BATTERY

Note. To identify relay wiring colors, see WIRING DIAGRAMS .

DTC B2588 indicates that ALC parking light relay output is shorted to battery. DTC B2588 will set when ignition switch is turned to RUN position, ALC option is enabled, ALC parking light output is active, and ALC parking light feedback does not exist for one second.

When DTC B2588 is set, ALC parking lights will turn off. DTC B2588 can be cleared when fault state is exited when status of ALC parking lights returns to OFF. DTC B2588 can also be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2588 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove ALC parking light relay from underhood wiring harness junction block. Replace ALC parking light relay with a known-good relay. Using scan tool, enable ALC parking light relay. If ALC parking light relay activates, go to step 8). If ALC parking light relay does not activate, go to next step.
  3. Remove ALC parking light relay from underhood wiring harness junction block. Back out underhood wiring harness junction block Brown 68-pin connector C3, terminal B8 (White wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B8 (White wire) and ground. If reading is zero volts, go to step 5). If reading is not zero volts, go to next step.
  4. Replace underhood wiring harness junction block. Go to step 8).
  5. Disconnect BFC Gray 16-pin connector C1, terminal B1 (White wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B8 (White wire) and ground. If reading is zero volts, go to next step. If reading is not zero volts, go to step 7).
  6. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 8).
  7. Repair short to battery in White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to next step.
  8. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2600: DRL ERROR

Note. All other DRL DTCs must be diagnosed before DTC B2600. See BFC DTC DEFINITIONS under SELF-DIAGNOSTIC SYSTEM.

DTC B600 indicates that a system problem has occurred that is preventing DRL system from operating properly. DTC B600 will set when ambient light sensor indicates bright conditions, DRL is configured to have a drop resistor and Ignition 3 is active, DRL relay output is active, and headlights operate improperly (low beams not in DRL range or high beams on) for more than 10 DRL relay on/off cycles.

When DTC B2600 is set, low beams will flicker on/off in bright conditions, DRL relay will turn off and SERVICE VEHICLE SOON indicator will illuminate. DTC B2600 can be cleared when fault state is exited when Ignition 3 becomes inactive. DTC B2600 can also be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2600 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. If any other DRL DTCs exist, go to next step. If no other DRL DTCs exist, go to step 4).
  3. Repair all other DRL DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) . If system is operating properly, go to step 7). If system is not operating properly, go to next step.
  4. Remove DRL relay from underhood wiring harness junction block. Replace DRL relay with a known-good relay. Using scan tool, enable DRL relay. If automatic lighting control operates properly, go to next step. If automatic lighting control does not operate properly, go to step 6).
  5. Clear DTCs. Check for DTCs. If DTC B2600 exists, go to next step. If DTC B2600 does not exist, go to step 7).
  6. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  7. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2602 indicates that DRL relay output is shorted to ground or open. DTC B2602 will set when DRL option is configured, Ignition 3 is active, DRL relay output is not active and DRL feedback exists for 5 seconds.

When DTC B602 is set, SERVICE VEHICLE SOON indicator will illuminate. DTC B2602 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

  1. Turn ignition switch to RUN position. Ensure transaxle range switch is not in Park position. Check for short to ground or open in circuits between BFC and underhood wiring harness junction block.
  2. If only history DTC B2602 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.
  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove DRL relay from underhood wiring harness junction block. Replace DRL relay with a known-good relay. Using scan tool,enable DRL relay. If automatic lighting control operates properly, go to step 10). If automatic light control does not operate properly, go to next step.
  3. Reinstall DRL relay. Back out underhood wiring harness junction block Brown 68-pin Brown connector C3, terminal B12 (Light Green/Black wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B12 (Light Green/Black wire) and ground. If battery voltage exists, go to step 5). If battery voltage does not exist, go to next step.
  4. Replace underhood wiring harness junction block. Go to step 10).
  5. Disconnect BFC Gray 16-pin connector C1, terminal B5 (Light Green/Black wire). Using DVOM, check resistance between BFC harness connector C1, terminal B5 (Light Green/Black wire) and ground. If resistance is infinite, go to step 7). If resistance is not infinite, go to next step.
  6. Repair short to ground in Light Green/Black wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  7. Using DVOM, check resistance between BFC harness connector C1, terminal B5 (Light Green/Black wire) and underhood wiring harness junction block harness connector C3, terminal B12 (Light Green/Black wire). If resistance is 0-2 ohms, go to step 9). If resistance is not 0-2 ohms, go to next step.
  8. Repair open in Light Green/Black wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  9. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  10. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2603 indicates that DRL relay output is shorted to battery. DTC B2603 will set when ignition switch is in RUN position, transaxle range switch is not in Park, DRL option is configured, DRL relay output is active and DRL feedback does not exist for 5 seconds.

When DTC B603 is set, DRL relay will turn off and SERVICE VEHICLE SOON indicator will illuminate. DTC B2603 can be cleared when fault state is exited when status of DRL returns to OFF. DTC B2603 can also be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2603 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove DRL relay from underhood wiring harness junction block. Replace DRL relay with a known-good relay. Using scan tool, enable DRL relay. If DRL relay activates, go to step 8). If DRL relay does not activate, go to next step.
  3. Remove DRL relay from underhood wiring harness junction block. Back out underhood wiring harness junction block Brown 68-pin connector C3, terminal B12 (Light Green/Black wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B12 (Light Green/Black wire) and ground. If reading is zero volts, go to step 5). If reading is not zero volts, go to next step.
  4. Replace underhood wiring harness junction block. Go to step 8).
  5. Disconnect BFC Gray 16-pin connector C1, terminal B5 (Light Green/Black wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B12 (Light Green/Black wire) and ground. If reading is zero volts, go to next step. If reading is not zero volts, go to step 7).
  6. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 8).
  7. Repair short to battery in Light Green/Black wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to next step.
  8. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

Circuit No. 341 (Brown wire) provides input from ignition switch to BFC. DTC B1379 will set when Ignition 3 is not active, and Ignition 1 is active for 20 seconds. See WIRING DIAGRAMS . DTC B1379 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only BFC is affected, low beams will not function when BFC is in Automatic Light Control (ALC) mode. If only history DTC B1379 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Turn ignition switch to RUN position. Disconnect BFC Gray 16-pin connector C1, terminal B8 (Brown wire). Using DVOM, check voltage between BFC harness connector C1, terminal B8 (Brown wire) and ground. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 6).
  3. Check for poor connection at BFC connector C1, terminal B8 (Brown wire). If a poor connection exists, go to next step. If connection is okay, go to step 5).
  4. Repair poor connection at BFC connector C1, terminal B8 (Brown wire). Go to step 11).
  5. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 11).
  6. Disconnect right I/P wiring junction block Natural 68-pin connector C1, terminal C4 (Brown wire). Using DVOM, check resistance between BFC harness connector C1, terminal B8 (Brown wire) and right I/P wiring harness junction block connector C1, terminal C4 (Brown wire). If resistance is 0-2 ohms, go to step 8). If resistance is not 0-2 ohms, go to next step.
  7. Repair open in Brown wire between BFC connector C1 and right I/P wiring harness junction block connector C1. Go to step 11).
  8. Check for a poor connection at right I/P wiring harness junction block connector C1, terminal C4 (Brown wire). If a poor connection exists, go to next step. If connection is okay, go to step 10).
  9. Repair poor connection at right I/P wiring harness junction block connector C1, terminal C4 (Brown wire). Go to step 11).
  10. Replace right I/P wiring harness junction block connector. Go to next step.
  11. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B1487 will set when a fault exists that is causing generator "L" terminal to read LOW continuously while engine is running. This DTC will be set when engine is running, PCM sends an "engine is running" class 2 data message, and PCM does not send an ""L" terminal high" class 2 data message for 30 seconds after vehicle has started. When DTC B1487 is set, VOLTS indicator will illuminate. DTC B1487 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B1487 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Run engine for more than one minute. Using DVOM, check voltage by backprobing between generator harness connector terminal "B" (Red wire) and ground. If battery voltage exists, go to step 9). If battery voltage does not exist, go to next step.
  3. Disconnect generator connector. On 2.4L, disconnect PCM Blue 80-pin connector C1. On 3.1L, disconnect PCM Clear 80-pin connector C2. On all models, use DVOM to check resistance between generator harness connector terminal "B" (Red wire) and ground. If resistance is infinite, go to next step. If resistance is not infinite, go to step 7).
  4. Reconnect all connectors and components. Run engine for more than one minute. Using DVOM, check voltage by backprobing between generator harness connector terminal "B" (Red wire) and ground. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 6).
  5. Using scan tool, read PCM "L" terminal input. If "L" terminal input is high, go to step 9). If "L" terminal is not high, go to step 8).
  6. Replace generator. See «GENERATOR & REGULATOR»(/chevrolet/malibu/v-1996-2000/remont/charging-system/#charging-system) article in ELECTRICAL. Go to step 9).
  7. Repair short to ground in Red wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 9).
  8. Replace PCM. See «REMOVE/INSTALL/OVERHAUL»(/chevrolet/malibu/v-1996-2000/remont/removal-installation/#how-to-overhaul-24l-the-engine-controls-removal-installation) article in ENGINE PERFORMANCE section. Go to next step.
  9. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B1488 will set when a fault exists that is causing generator "L" terminal to read HIGH continuously. This DTC will be set when Ignition 1 is active, engine is off and PCM is sending an ""L" terminal high" class 2 data message for 30 seconds. When DTC B1488 is set, VOLTS indicator will illuminate. DTC B1487 can be cleared using scan tool.

With engine off, check for a short to battery in circuit No. 225 (Red wire) between PCM and generator. If only history DTC B1488 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Turn ignition switch to RUN position, with engine off. Using DVOM, check voltage by backprobing between generator harness connector terminal "B" (Red wire) and ground. If about zero volts exists, go to step 5). If about zero volts does not exist, go to next step.
  3. Disconnect generator connector. On 2.4L, disconnect PCM Blue 80-pin connector C1. On 3.1L, disconnect PCM Clear 80-pin connector C2. On 2.4L, use DVOM to check resistance between PCM harness connector C1, terminal No. 74 (Red wire) and generator harness connector terminal "B" (Red wire). On 3.1L, use DVOM to check resistance between PCM harness connector C2, terminal No. 35 (Red wire) and generator connector terminal "B" (Red wire). If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 7).
  4. Reconnect all connectors and components. Turn ignition switch to RUN position, with engine off. On 2.4L, use DVOM to check voltage by backprobing between PCM harness connector C1, terminal No. 74 (Red wire) and ground. On 3.1L, use DVOM to check voltage by backprobing between PCM harness connector C2, terminal No. 35 (Red wire) and ground. If battery voltage exists, go to step 6). If battery voltage does not exist, go to step 8).
  5. Using scan tool, read PCM "L" terminal status. If "L" terminal input is low, go to step 9). If "L" terminal is not low, go to step 8).
  6. Replace generator. See «GENERATOR & REGULATOR»(/chevrolet/malibu/v-1996-2000/remont/charging-system/#charging-system) article in ELECTRICAL. Go to step 9).
  7. Repair open in Red wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 9).
  8. Replace PCM. See «REMOVE/INSTALL/OVERHAUL»(/chevrolet/malibu/v-1996-2000/remont/removal-installation/#how-to-overhaul-24l-the-engine-controls-removal-installation) article in ENGINE PERFORMANCE section. Go to next step.
  9. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B1492 will set when a fault exists that is causing generator PWM to read LOW continuously. This DTC will be set when PCM is sending "engine is running" and "generator PWM is less than 1.96 percent" class 2 data messages, field terminal present calibration is enabled in PCM, and engine is running at about 3000 RPM for 30 seconds.

When DTC B1492 is set, VOLTS indicator will illuminate. DTC B1492 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

When engine is running, generator "F" terminal should be low. If only history DTC B1492 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. On 2.4L, disconnect PCM Blue 80-pin connector C1, terminal No. 53 (Gray wire). On 3.1L, disconnect PCM Clear 80-pin connector C2, terminal No. 62 (Gray wire). Disconnect generator connector. On 2.4L, use DVOM to check resistance between PCM harness connector C1, terminal No. 53 (Gray wire) and ground. On 3.1L, use DVOM to check resistance between PCM harness connector C2, terminal No. 62 (Gray wire) and ground. If resistance is infinite, go to step 4). If resistance is not infinite, go to next step.
  3. Repair short to ground in Gray wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 10).
  4. On 2.4L, use DVOM to check resistance between PCM harness connector C1, terminal No. 53 (Gray wire) and generator harness connector terminal "C" (Gray wire). On 3.1L, use DVOM to check resistance between PCM harness connector C2, terminal No. 62 (Gray wire) and generator harness connector terminal "C" (Gray wire). If resistance is 0-2 ohms, go to step 6). If resistance is not 0-2 ohms, go to next step.
  5. Repair open in Gray wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 10).
  6. Connect a fused jumper wire between generator terminals "C" (Gray wire) and "D" (Orange wire). Start engine. Using scan tool, read generator PWM. If scan tool displays greater than 50 percent, go to next step. If scan tool does not display greater than 50 percent, go to step 8).
  7. Start engine. Repeatedly reconnect and disconnect generator connector. Using scan tool, read PCM generator PWM status. If PCM generator PWM oscillates, go to step 10). If PCM generator PWM does not oscillate, go to step 9).
  8. Replace PCM. See «REMOVE/INSTALL/OVERHAUL»(/chevrolet/malibu/v-1996-2000/remont/removal-installation/#how-to-overhaul-24l-the-engine-controls-removal-installation) article in ENGINE PERFORMANCE section. Go to step 10).
  9. Replace generator. See «GENERATOR & REGULATOR»(/chevrolet/malibu/v-1996-2000/remont/charging-system/#charging-system) article in ELECTRICAL section. Go to next step.
  10. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B1493 will set when a fault exists that is causing generator "F" terminal to read HIGH continuously. This DTC will be set when engine is running, and PCM is sending "engine RPM is zero" and "generator PWM is equal to or greater than 64 percent duty cycle" class 2 data messages for 30 seconds. When DTC B1493 is set, VOLTS indicator will illuminate. DTC B1493 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B1493 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Turn ignition switch to RUN position, with engine off. Disconnect generator connector. Using scan tool, read generator PWM. If scan tool displays zero percent, go to next step. If scan tool does not display zero percent, go to step 5).
  3. Reconnect generator connector. Start engine. Using scan tool, read generator PWM from PCM. If scan tool displays greater than 50 percent, go to next step. If scan tool does not display greater than 50 percent, go to step 5).
  4. Replace generator. See «GENERATOR & REGULATOR»(/chevrolet/malibu/v-1996-2000/remont/charging-system/#charging-system) article in ELECTRICAL section. Go to next step.
  5. Disconnect generator connector. On 2.4L, disconnect PCM Blue 80-pin connector C1. On 3.1L, disconnect PCM Clear 80-pin connector C2. On all models, use DVOM to check voltage at generator terminal "C" (Gray wire). If reading is zero volts, go to step 7). If reading is not zero volts, go to next step.
  6. Repair short to battery in Gray wire between generator and PCM connector C1 (2.4L) or connector C2 (3.1L). Go to step 8).
  7. Replace PCM. See «REMOVE/INSTALL/OVERHAUL»(/chevrolet/malibu/v-1996-2000/remont/removal-installation/#how-to-overhaul-24l-the-engine-controls-removal-installation) article in ENGINE PERFORMANCE section. Go to next step.
  8. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

Note. To identify relay wiring colors, see WIRING DIAGRAMS .

BFC uses circuit No. 1317 (Dark Green/White wire) to ground front foglight relay. DTC B2532 will set when Ignition 1 is active and front foglight switch is not active. DTC B2532 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

Foglights will only illuminate when parking lights are on and foglight switch is actuated. If only history DTC B2532 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove front foglight relay from right I/P wiring harness junction block. Replace foglight relay with a known-good relay. Using scan tool, enable front foglight relay. If front foglight operates properly, go to step 10). If front foglight does not operate properly, go to next step.
  3. Reinstall original foglight relay. Back out right I/P wiring harness junction block Natural 68-pin connector C1, terminal F3 (Dark Green/White wire). Using DVOM, check voltage between right I/P wiring harness junction block connector C1, terminal F3 (Dark Green/White wire) and ground. If battery voltage exists, go to step 5). If battery voltage does not exist, go to next step.
  4. Replace right I/P wiring harness junction block. Go to step 10).
  5. Disconnect BFC Gray 16-pin connector C1, terminal A2 (Dark Green/White wire). Using DVOM, check resistance between BFC connector C1, terminal A2 (Dark Green/White wire) and ground. If resistance is infinite, go to step 7). If resistance is not infinite, go to next step.
  6. Repair short to ground in Dark Green/White wire between BFC connector C1 and right I/P wiring harness junction block connector C1. Go to step 10).
  7. Using DVOM, check resistance between BFC connector C1, terminal A2 (Dark Green/White wire) and right I/P wiring harness junction block connector C1, terminal F3 (Dark Green/White wire). If resistance is 0-2 ohms, go to step 9). If resistance is not 0-2 ohms, go to next step.
  8. Repair open in Dark Green/White wire between BFC connector C1 and right I/P wiring harness junction block connector C1. Go to step 10).
  9. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  10. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

BFC uses circuit No. 1317 (Dark Green/White wire) to ground front foglight relay. DTC B2533 will set when parking lights are commanded on (manually or using ALC function), BFC enables front foglight option, Ignition 1 is active and front foglight relay output is on. When DTC B2533 is set, front foglight will turn off. DTC B2533 can be cleared when fault state is exited when status of front foglight returns to OFF. DTC B2533 can also be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2533 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove front foglight relay from right I/P wiring harness junction block. Replace foglight relay with a known-good relay. Using scan tool, enable front foglight relay. If front foglight operates properly, go to step 8). If front foglight does not operate properly, go to next step.
  3. Remove foglight relay. Back out right I/P wiring harness junction block Natural 68-pin connector C1, terminal F3 (Dark Green/White wire). Using DVOM, check voltage between right I/P wiring harness junction block connector C1, terminal F3 (Dark Green/White wire) and ground. If reading is zero volts, go to step 5). If reading is not zero volts, go to next step.
  4. Replace right I/P wiring harness junction block. Go to step 8).
  5. Disconnect BFC Gray 16-pin connector C1, terminal A2 (Dark Green/White wire). Using DVOM, check voltage between right I/P wiring harness junction block connector C1, terminal F3 (Dark Green/White wire) and ground. If reading is zero volts, go to next step. If reading is not zero volts, go to step 7).
  6. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 8).
  7. Repair short to battery in Dark Green/White wire between BFC connector C1 and right I/P wiring harness junction block connector C1. Go to next step.
  8. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

BFC uses circuit No. 156 (White wire) to ground interior lights. DTC B2558 will set when interior light relay is on (but not in theater or step dim lighting modes) and interior light feedback from circuit No. 156 (White wire) does not exist for .5 second. When DTC B2558 is set, interior light relay will turn off. DTC B2558 can be cleared when fault state is exited when status of interior lights returns to OFF. DTC B2558 can also be cleared using scan tool or when fault conditions no longer exist.

If only history DTC B2558 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect BFC Pink 24-pin connector C3. Remove left and right courtesy lights. Turn dome switch to OFF position. Using DVOM, check voltage between BFC harness connector C3, terminal A11 (White wire) and ground. If zero volts exists, go to step 10). If zero volts does not exist, go to next step.
  3. Disconnect left I/P wiring harness junction block Brown 68-pin connector C1. Disconnect left I/P wiring harness junction block Gray 30-pin connector C2. Disconnect left I/P wiring harness junction block Black 30-pin connector C3. Using DVOM, check voltage between BFC harness connector C3, terminal A11 (White wire) and ground. If zero volts exists, go to step 5). If zero volts does not exist, go to next step.
  4. Repair short to battery in White wire between BFC connector C3 and left I/P wiring harness junction block connector C1. Go to step 11).
  5. Using DVOM, check voltage between left I/P wiring harness junction block Gray 30-pin harness connector C2, terminal C3 (White wire) and ground. If zero volts exists, go to step 7). If zero volts does not exist, go to next step.
  6. Repair short to battery in White wire between left I/P wiring harness junction block connector C2 and left and right courtesy lights. Go to step 11).
  7. Using DVOM, check voltage between left I/P wiring harness junction block Black 30-pin harness connector C3, terminal C10 (White wire) and ground. If zero volts exists, go to step 9). If zero volts does not exist, go to next step.
  8. Repair short to battery in White wire between left I/P wiring harness junction block connector C3 and dome light. Go to step 11).
  9. Replace left I/P wiring harness junction block. Go to step 11).
  10. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  11. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

BFC uses circuit No. 1970 (Pink/White wire) to ground ALC relay coil. DTC B2575 indicates that headlights were not on when ALC relay output was on. DTC B2575 will set when ALC option is enabled and Ignition 1 is active, ALC headlight output is active, high beams are not on (may be off or in DRL mode) and low beams are off for 5 seconds. When DTC B2575 is set, SERVICE VEHICLE SOON indicator will illuminate. DTC B2575 can be cleared when BFC reads proper headlight voltage, using scan tool or when fault conditions no longer exist.

  1. Turn ignition switch to RUN position. Cover ambient light sensor for 30 seconds. Low beams should illuminate. If low beams do not illuminate, see «WIRING DIAGRAMS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) .
  2. Turn ignition switch to RUN position. Turn high beams on. Cover ambient light sensor for 30 seconds. High beams should illuminate. If high beams do not illuminate, see «WIRING DIAGRAMS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) .
  3. If only history DTC B2575 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.
  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. If no other ALC DTCs exist, go to next step. If any other ALC DTCs exist, repair those DTCs first.
  3. Turn low beam headlights on. If both low beam headlights illuminate, go to next step. If both low beam headlights do not illuminate, go to step 7).
  4. Using scan tool, read BFC INPUT for LOW BEAM/DRL FEEDBACK. If scan tool displays DRL ON, go to next step. If scan tool does not display DRL ON, go to step 7).
  5. Turn high beam headlights on. If both high beam headlights illuminate, go to next step. If both high beam headlights do not illuminate, go to step 7).
  6. Using scan tool, read BFC INPUT for HIGH BEAM FEEDBACK. If scan tool displays HIGH BEAMS ON, go to step 10). If scan tool does not display HIGH BEAMS ON, go to next step.
  7. Locate problem in headlight and DRL system. See «WIRING DIAGRAMS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) . Repair as necessary. If repair is complete, go to step 11). If repair is not complete, go to next step.
  8. Remove DRL relay from underhood wiring harness junction block. Replace DRL relay with a known-good relay. Using scan tool, enable DRL relay. If automatic lighting control operates properly, go to step 11). If automatic light control does not operate properly, go to next step.
  9. Remove ALC headlight relay from underhood wiring harness junction block. Replace ALC headlight relay with a known-good relay. Using scan tool, enable ALC headlight relay. If automatic lighting control operates properly, go to step 11). If automatic light control does not operate properly, go to next step.
  10. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  11. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

Note. To identify relay wiring colors, see WIRING DIAGRAMS .

DTC B2577 indicates that ALC headlight relay output is shorted to ground or open. DTC B2577 will set when ambient light sensor indicates bright conditions, ALC option is enabled and Ignition 1 is active, engine is not being cranked ("Ignition 1 active, Ignition 3 inactive and engine not running" class 2 data message), ALC headlight output is not active and ALC headlight feedback exists for 5 seconds.

When DTC B2577 is set, SERVICE VEHICLE SOON indicator will illuminate. DTC B2577 can be cleared when BFC reads proper headlight voltage or using scan tool. History DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2577 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove ALC headlight relay from underhood wiring harness junction block. Replace ALC headlight relay with a known-good relay. Using scan tool, enable ALC headlight relay. If automatic lighting control operates properly, go to step 10). If automatic light control does not operate properly, go to next step.
  3. Reconnect ALC headlight relay. Back out underhood wiring harness junction block Brown 68-pin Brown connector C3, terminal C11 (Pink/White wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal C11 (Pink/White wire) and ground. If battery voltage exists, go to step 5). If battery voltage does not exist, go to next step.
  4. Replace underhood wiring harness junction block. Go to step 10).
  5. Disconnect BFC Gray 16-pin connector C1, terminal A1 (Pink/White wire). Using DVOM, check resistance between BFC harness connector C1, terminal A1 (Pink/White wire) and ground. If resistance is infinite, go to step 7). If resistance is not infinite, go to next step.
  6. Repair short to ground in Pink/White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  7. Using DVOM, check resistance between BFC harness connector C1, terminal A1 (Pink/White wire) and underhood wiring harness junction block harness connector C3, terminal C11 (Pink/White wire). If resistance is 0-2 ohms, go to step 9). If resistance is not 0-2 ohms, go to next step.
  8. Repair open in Pink/White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  9. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  10. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2578 indicates that ALC headlight relay output is shorted to battery. DTC B2578 will set when ambient light sensor indicates bright conditions, ALC option is enabled, ALC headlight output is active and ALC headlight feedback does not exist for one second.

When DTC B2578 is set, ALC headlight relay will turn off and SERVICE VEHICLE SOON indicator will illuminate. DTC B2578 can be cleared when fault state is exited when status of ALC headlights returns to OFF. DTC B2578 can also be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2578 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove ALC headlight relay from underhood wiring harness junction block. Replace ALC headlight relay with a known-good relay. Using scan tool, enable ALC headlight relay. If ALC headlight relay activates, go to step 8). If ALC headlight relay does not activate, go to next step.
  3. Remove ALC headlight relay from underhood wiring harness junction block. Back out underhood wiring harness junction block Brown 68-pin connector C3, terminal C11 (Pink/White wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal C11 (Pink/White wire) and ground. If reading is zero volts, go to step 5). If reading is not zero volts, go to next step.
  4. Replace underhood wiring harness junction block. Go to step 8).
  5. Disconnect BFC Gray 16-pin connector C1, terminal A1 (Pink/White wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal C11 (Pink/White wire) and ground. If reading is zero volts, go to next step. If reading is not zero volts, go to step 7).
  6. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 8).
  7. Repair short to battery in Pink/White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to next step.
  8. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2585 indicates that parking lights were not on when ALC headlight relay output is on. DTC B2585 will set when ALC option is enabled and Ignition 1 is active, ALC parking light output is active, and parking lights' active discrete input is not active for 5 seconds.

When DTC B2585 is set, SERVICE VEHICLE SOON indicator will illuminate. DTC B2585 can be cleared when BFC reads proper parking light voltage. DTC B2578 can also be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If battery voltage exists at BFC parking relay output, check ALC parking light relay and circuits. Check multifunction switch. See STEERING COLUMN SWITCHES article. Also see WIRING DIAGRAMS. If only history DTC B2585 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. If no other ALC DTCs exist, go to next step. If any other ALC DTCs exist, repair those DTCs first.
  3. Turn parking lights on. If all parking lights illuminate, go to next step. If all parking lights do not illuminate, go to step 5).
  4. Toggle parking lights on and off. Using scan tool, read BFC INPUT for PARK LAMP INPUT. If scan tool display toggles, go to step 12). If scan tool display does not toggle, go to next step.
  5. If scan tool displays INACTIVE while parking lights are toggled on and off, go to next step. If scan tool does not display INACTIVE while parking lights are toggled on and off, go to step 7).
  6. Locate and repair problem in audible warning system.
  7. Disconnect right I/P wiring harness junction block Gray 30-pin connector C2, terminal C10 (Brown wire). Disconnect BFC Gray 24-pin connector C2, terminal B8 (Brown wire). Using DVOM, check resistance between right I/P wiring harness junction block harness connector C2, terminal C10 (Brown wire) and BFC harness connector C2, terminal B8 (Brown wire). If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 9).
  8. Using DVOM, check resistance between right I/P wiring harness junction block harness connector C2, terminal C10 (Brown wire) and ground. If resistance is infinite, go to step 11). If resistance is not infinite, go to step 10).
  9. Repair open in Brown wire between BFC connector C2 and right I/P wiring harness junction block connector C2. Go to step 12).
  10. Repair short to ground in Brown wire between BFC connector C2 and right I/P wiring harness junction block connector C2. Go to step 12).
  11. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  12. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

Note. To identify relay wiring colors, see WIRING DIAGRAMS .

DTC B2587 indicates that ALC parking light relay output is shorted to ground or open. DTC B2587 will set when ALC option is enabled and Ignition 1 is active, ALC parking light output is not active, and ALC parking light feedback exists for 5 seconds.

When DTC B2587 is set, SERVICE VEHICLE SOON indicator will illuminate. DTC B2587 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2587 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove ALC parking light relay from underhood wiring harness junction block. Replace ALC parking light relay with a known-good relay. Using scan tool, enable ALC parking light relay. If ALC parking light relay operates properly, go to step 10). If ALC parking light relay does not operate properly, go to next step.
  3. Ensure ALC parking light relay is installed in underhood wiring harness junction block. Back out underhood wiring harness junction block Brown 68-pin connector C3, terminal B8 (White wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B8 (White wire) and ground. If battery voltage exists, go to step 5). If battery voltage does not exist, go to next step.
  4. Replace underhood wiring harness junction block. Go to step 10).
  5. Disconnect BFC Gray 16-pin connector C1, terminal B1 (White wire). Using DVOM, check resistance between BFC harness connector C1, terminal B1 (White wire) and ground. If resistance is infinite, go to step 7). If resistance is not infinite, go to next step.
  6. Repair short to ground in White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  7. Using DVOM, check resistance between BFC harness connector C1, terminal B1 (White wire) and underhood wiring harness junction block connector C3, terminal B8 (White wire). If resistance is 0-2 ohms, go to step 9). If resistance is not 0-2 ohms, go to next step.
  8. Repair open in White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  9. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  10. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

Note. To identify relay wiring colors, see WIRING DIAGRAMS .

DTC B2588 indicates that ALC parking light relay output is shorted to battery. DTC B2588 will set when ignition switch is turned to RUN position, ALC option is enabled, ALC parking light output is active, and ALC parking light feedback does not exist for one second.

When DTC B2588 is set, ALC parking lights will turn off. DTC B2588 can be cleared when fault state is exited when status of ALC parking lights returns to OFF. DTC B2588 can also be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2588 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove ALC parking light relay from underhood wiring harness junction block. Replace ALC parking light relay with a known-good relay. Using scan tool, enable ALC parking light relay. If ALC parking light relay activates, go to step 8). If ALC parking light relay does not activate, go to next step.
  3. Remove ALC parking light relay from underhood wiring harness junction block. Back out underhood wiring harness junction block Brown 68-pin connector C3, terminal B8 (White wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B8 (White wire) and ground. If reading is zero volts, go to step 5). If reading is not zero volts, go to next step.
  4. Replace underhood wiring harness junction block. Go to step 8).
  5. Disconnect BFC Gray 16-pin connector C1, terminal B1 (White wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B8 (White wire) and ground. If reading is zero volts, go to next step. If reading is not zero volts, go to step 7).
  6. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 8).
  7. Repair short to battery in White wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to next step.
  8. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

Note. All other DRL DTCs must be diagnosed before DTC B2600. See BFC DTC DEFINITIONS under SELF-DIAGNOSTIC SYSTEM.

DTC B600 indicates that a system problem has occurred that is preventing DRL system from operating properly. DTC B600 will set when ambient light sensor indicates bright conditions, DRL is configured to have a drop resistor and Ignition 3 is active, DRL relay output is active, and headlights operate improperly (low beams not in DRL range or high beams on) for more than 10 DRL relay on/off cycles.

When DTC B2600 is set, low beams will flicker on/off in bright conditions, DRL relay will turn off and SERVICE VEHICLE SOON indicator will illuminate. DTC B2600 can be cleared when fault state is exited when Ignition 3 becomes inactive. DTC B2600 can also be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2600 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. If any other DRL DTCs exist, go to next step. If no other DRL DTCs exist, go to step 4).
  3. Repair all other DRL DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) . If system is operating properly, go to step 7). If system is not operating properly, go to next step.
  4. Remove DRL relay from underhood wiring harness junction block. Replace DRL relay with a known-good relay. Using scan tool, enable DRL relay. If automatic lighting control operates properly, go to next step. If automatic lighting control does not operate properly, go to step 6).
  5. Clear DTCs. Check for DTCs. If DTC B2600 exists, go to next step. If DTC B2600 does not exist, go to step 7).
  6. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  7. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2602 indicates that DRL relay output is shorted to ground or open. DTC B2602 will set when DRL option is configured, Ignition 3 is active, DRL relay output is not active and DRL feedback exists for 5 seconds.

When DTC B602 is set, SERVICE VEHICLE SOON indicator will illuminate. DTC B2602 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

  1. Turn ignition switch to RUN position. Ensure transaxle range switch is not in Park position. Check for short to ground or open in circuits between BFC and underhood wiring harness junction block.
  2. If only history DTC B2602 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.
  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove DRL relay from underhood wiring harness junction block. Replace DRL relay with a known-good relay. Using scan tool,enable DRL relay. If automatic lighting control operates properly, go to step 10). If automatic light control does not operate properly, go to next step.
  3. Reinstall DRL relay. Back out underhood wiring harness junction block Brown 68-pin Brown connector C3, terminal B12 (Light Green/Black wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B12 (Light Green/Black wire) and ground. If battery voltage exists, go to step 5). If battery voltage does not exist, go to next step.
  4. Replace underhood wiring harness junction block. Go to step 10).
  5. Disconnect BFC Gray 16-pin connector C1, terminal B5 (Light Green/Black wire). Using DVOM, check resistance between BFC harness connector C1, terminal B5 (Light Green/Black wire) and ground. If resistance is infinite, go to step 7). If resistance is not infinite, go to next step.
  6. Repair short to ground in Light Green/Black wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  7. Using DVOM, check resistance between BFC harness connector C1, terminal B5 (Light Green/Black wire) and underhood wiring harness junction block harness connector C3, terminal B12 (Light Green/Black wire). If resistance is 0-2 ohms, go to step 9). If resistance is not 0-2 ohms, go to next step.
  8. Repair open in Light Green/Black wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to step 10).
  9. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  10. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2603 indicates that DRL relay output is shorted to battery. DTC B2603 will set when ignition switch is in RUN position, transaxle range switch is not in Park, DRL option is configured, DRL relay output is active and DRL feedback does not exist for 5 seconds.

When DTC B603 is set, DRL relay will turn off and SERVICE VEHICLE SOON indicator will illuminate. DTC B2603 can be cleared when fault state is exited when status of DRL returns to OFF. DTC B2603 can also be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2603 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Remove DRL relay from underhood wiring harness junction block. Replace DRL relay with a known-good relay. Using scan tool, enable DRL relay. If DRL relay activates, go to step 8). If DRL relay does not activate, go to next step.
  3. Remove DRL relay from underhood wiring harness junction block. Back out underhood wiring harness junction block Brown 68-pin connector C3, terminal B12 (Light Green/Black wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B12 (Light Green/Black wire) and ground. If reading is zero volts, go to step 5). If reading is not zero volts, go to next step.
  4. Replace underhood wiring harness junction block. Go to step 8).
  5. Disconnect BFC Gray 16-pin connector C1, terminal B5 (Light Green/Black wire). Using DVOM, check voltage between underhood wiring harness junction block connector C3, terminal B12 (Light Green/Black wire) and ground. If reading is zero volts, go to next step. If reading is not zero volts, go to step 7).
  6. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 8).
  7. Repair short to battery in Light Green/Black wire between BFC connector C1 and underhood wiring harness junction block connector C3. Go to next step.
  8. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2647 indicates that ambient light sensor is shorted to ground or open. DTC B2647 will set when ALC option is enabled, Ignition 1 is active, and ambient light sensor analog input is 5 counts or less for 5 seconds.

When DTC B2647 is set, headlights will stay on at all times at full intensity. DTC B2647 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2647 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect ambient light sensor from top of instrument panel. Disconnect BFC Gray 24-pin connector C2. Using DVOM, check resistance between ambient light sensor harness terminal "B" (Yellow/Black wire) and ground. If resistance is infinite, go to step 4). If resistance is not infinite, go to next step.
  3. Repair short to ground in Yellow/Black wire between ambient light sensor and BFC connector C2. Go to step 7).
  4. Using DVOM, check resistance between ambient light sensor harness terminal "B" (Yellow/Black wire) and BFC harness connector C2, terminal A3 (Yellow/Black wire). If resistance is 0-2 ohms, go to step 6). If resistance is not 0-2 ohms, go to next step.
  5. Repair open in Yellow/Black wire between ambient light sensor and BFC connector C2. Go to step 9).
  6. Replace ambient light sensor. Go to next step.
  7. Reconnect all disconnected components. Clear DTCs. Check for DTCs. If DTC B2647 exists, go to next step. If DTC B2647 does not exist, go to step 9).
  8. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  9. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2648 indicates that ambient light sensor is shorted to battery. DTC B2648 will set when ALC option is enabled, Ignition 1 is active, and ambient light sensor analog input is 250 counts or more for 5 seconds.

When DTC B2648 is set, headlights will be on at reduced DRL intensity at night and SERVICE VEHICLE SOON indicator will illuminate. DTC B2648 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2648 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect BFC Gray 24-pin connector C2. Disconnect ambient light sensor from top of instrument panel. Using DVOM, check voltage between ambient light sensor harness terminal "B" (Yellow/Black wire) and ground. If reading is zero volts, go to step 4). If reading is not zero volts, go to next step.
  3. Repair short to battery in Yellow/Black wire between ambient light sensor and BFC connector C2. Go to step 5).
  4. Replace ambient light sensor. Go to next step.
  5. Reconnect all disconnected components. Clear DTCs. Check for DTCs. If DTC B2648 exists, go to next step. If DTC B2648 does not exist, go to step 7).
  6. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  7. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC B2965 will set when key-in-ignition input is not active and Ignition 0 is active for 20 seconds. DTC B2965 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC B2965 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect ignition switch Natural 6-pin connector C1. Using scan tool, read BFC INPUT for KEY IN IGNITION. Connect a fused jumper wire between ignition switch connector C1, terminal "D" (Light Green wire) and ground. If scan tool displays KEY IN IGNITION YES, go to step 5). If scan tool does not display KEY IN IGNITION YES, go to next step.
  3. Back out BFC Gray 24-pin connector C2, terminal B12 (Light Green wire). Using scan tool, read BFC INPUT for KEY IN IGNITION. Connect a fused jumper wire between BFC harness connector C2, terminal B12 (Light Green wire) and ground. If scan tool displays KEY IN IGNITION YES, go to next step. If scan tool does not display KEY IN IGNITION YES, go to step 8).
  4. Repair open in Light Green wire between ignition switch and BFC connector C2. Go to step 9).
  5. Using DVOM, check resistance of Black/White wire between ignition switch Black 6-pin connector, terminal "E" and ground splice pack G202 (located above left I/P wiring harness junction block). If resistance is 0-2 ohms, go to step 7). If resistance is not 0-2 ohms, go to next step.
  6. Repair open in Black/White wire between ignition switch Black6-pin connector, terminal "E" and ground splice pack G202. Go to step 9).
  7. Replace ignition switch. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article.
  8. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  9. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC P0462 indicates that BFC fuel sensor input is shorted to ground. DTC P0462 will set when Ignition 0 is active and ratio of fuel level voltage to battery voltage is less than one percent for 2.55 seconds.

When DTC P0462 is set, fuel gauge will display empty and LOW FUEL indicator will illuminate. DTC P0462 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC P0462 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect fuel tank module connector. Using scan tool, check resistance of Black/White wire at fuel tank module harness connector terminal "D". If resistance is greater than 250 ohms, go to step 9). If resistance is not greater than 250 ohms, go to next step.
  3. Back out left I/P wiring harness junction block Black 30-pin connector C3, terminal A12 (Black/White wire). Using scan tool, check resistance of Black/White wire at fuel tank module harness connector terminal "D". If resistance is greater than 250 ohms, go to step 5). If resistance is not greater than 250 ohms, go to next step.
  4. Repair short to ground in Black/White wire between left I/P wiring harness junction block connector C3 and fuel tank module. Go to step 12).
  5. Back out left I/P wiring harness junction block Gray 30-pin connector C2, terminal A1 (Black wire). Using scan tool, check resistance of Black/White wire at fuel tank module harness connector terminal "D". If resistance is greater than 250 ohms, go to step 8). If resistance is not greater than 250 ohms, go to next step.
  6. Using DVOM, check resistance between left I/P wiring harness junction block connector C2, terminal A1 (Black wire) and ground. If resistance is infinite, go to step 9). If resistance is not infinite, go to next step.
  7. Repair short to ground in Black wire between left I/P wiring harness junction block connector C2 and BFC connector C2. Go to step 12).
  8. Replace left I/P wiring harness junction block. Go to step 12).
  9. Reconnect all disconnected components. Replace fuel tank module. Go to next step.
  10. Clear DTCs. Check for DTCs. If DTC P0462 exists, go to next step. If DTC P0462 does not exist, go to step 12).
  11. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  12. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC P0463 indicates that BFC fuel sensor input is shorted to battery or open. DTC P0463 will set when Ignition 0 is active and analog fuel input is 255 counts for 2.55 seconds.

When DTC P0463 is set, fuel gauge will display empty and LOW FUEL indicator will illuminate. DTC P0463 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC P0463 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect BFC Gray 24-pin connector C2, terminal A4 (Black wire). Disconnect fuel tank module connector. Using DVOM, check voltage between BFC connector C2, terminal A4 (Black wire) and ground. If zero volts exists, go to next step. If zero volts does not exist, go to step 8).
  3. Back out left I/P wiring harness junction block Black 30-pin connector C3, terminal A12 (Black/White wire). Using DVOM, check resistance between left I/P wiring harness junction block connector C3, terminal A12 (Black/White wire) and fuel tank module harness connector terminal "D" (Black/White wire). If resistance is 0-2 ohms, go to step 5). If resistance is not 0-2 ohms, go to next step.
  4. Repair open in Black/White wire between left I/P wiring harness junction block connector C3 and fuel tank module. Go to step 16).
  5. Back out left I/P wiring harness junction block Gray 30-pin connector C2, terminal A1 (Black wire). Using DVOM, check resistance between left I/P wiring harness junction block connector C2, terminal A1 (Black wire) and left I/P wiring harness junction block connector C3, terminal A12 (Black/White wire). If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 12).
  6. Using DVOM, check resistance between left I/P wiring harness junction block connector C2, terminal A1 (Black wire) and BFC Gray 24-pin connector C2, terminal A4 (Black wire). If resistance is 0-2 ohms, go to step 13). If resistance is not 0-2 ohms, go to next step.
  7. Repair open in Black wire between left I/P wiring harness junction block connector C2 and BFC connector C2. Go to step 16).
  8. Back out left I/P wiring harness junction block Black 30-pin connector C3, terminal A12 (Black/White wire). Using DVOM, check voltage between left I/P wiring harness junction block connector C3, terminal A12 (Black/White wire) and fuel tank module harness connector terminal "D" (Black/White wire). If zero volts exists, go to step 10). If zero volts does not exist, go to next step.
  9. Repair short to battery in Black/White wire between left I/P wiring harness junction block connector C3 and fuel tank module. Go to step 16).
  10. Disconnect left I/P wiring harness junction block Gray 30-pin connector C2, terminal A1 (Black wire). Using DVOM, check voltage between left I/P wiring harness junction block connector C2, terminal A1 (Black wire) and ground. If reading is zero volts, go to step 12). If reading is not zero volts, go to next step.
  11. Repair short to battery in Black wire between left I/P wiring harness junction block connector C2 and BFC connector C2. Go to step 16).
  12. Replace left I/P wiring harness junction block. Go to step 16).
  13. Reconnect all disconnected components. Replace fuel tank module. Go to next step.
  14. Clear DTCs. Check for DTCs. If DTC P0463 exists, go to next step. If DTC P0463 does not exist, go to step 16).
  15. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  16. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC U1000 indicates that BFC has lost class 2 serial communication with EBCM or PCM when ignition switch was first turned to ON or RUN position. DTC U1000 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC U1000 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Connect scan tool. Turn ignition switch to RUN position. Using scan tool, establish communication with BFC. If communication can be established, go to next step. If communication cannot be established, go to step 4).
  3. Using scan tool, establish communication with other modules. If communication can be established, go to step 5). If communication cannot be established, go to next step.
  4. Locate and repair problem in DLC system. See «WIRING DIAGRAMS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) . Go to step 7).
  5. Clear DTCs. Check for DTCs. If DTC U1000 exists, go to next step. If DTC U1000 does not exist, go to step 7).
  6. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  7. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC U1016 indicates that BFC has lost class 2 serial communication with PCM for 15 seconds. When DTC U1016 is set, failsoft data associated with DTC U1016 is stored in PCM. DTC U1016 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

If only history DTC U1016 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Connect scan tool. Turn ignition switch to RUN position. Using scan tool, establish communication with PCM. If communication can be established, go to next step. If communication cannot be established, go to step 4).
  3. Diagnose and repair problem in PCM. See «TESTS W/CODES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l) article in ENGINE PERFORMANCE section. Go to step 8).
  4. Using scan tool, establish communication with other modules. If communication can be established, go to step 6). If communication cannot be established, go to next step.
  5. Locate and repair problem in DLC system. See «WIRING DIAGRAMS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) . Go to step 8).
  6. Clear DTCs. Check for DTCs. If DTC U1016 exists, go to next step. If DTC U1016 does not exist, go to step 8).
  7. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  8. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC U1040 indicates that BFC has lost class 2 serial communication with EBCM for 15 seconds. When DTC U1040 is set, failsoft data associated with DTC U1040 is stored in EBCM. DTC U1040 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

When DTC U1040 is set, ABS and BRAKE indicators will be illuminated. If only history DTC U1040 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Connect scan tool. Turn ignition switch to RUN position. Using scan tool, establish communication with EBCM. If communication can be established, go to next step. If communication cannot be established, go to step 4).
  3. See ANTI-LOCK BRAKES article in BRAKES section. Go to step 8).
  4. Using scan tool, establish communication with other modules. If communication can be established, go to step 6). If communication cannot be established, go to next step.
  5. Locate and repair problem in DLC system. See «WIRING DIAGRAMS»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module) . Go to step 8).
  6. Clear DTCs. Check for DTCs. If DTC U1040 exists, go to next step. If DTC U1040 does not exist, go to step 8).
  7. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  8. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC U2000: INVALID BFC TRANSMITTED SPI DATA

Note. DTC U2001 must be diagnosed before DTC U2000.

DTC U2000 indicates that instrument cluster has detected a loss of SPI data from BFC. DTC U2000 will set when Ignition 0 is active, and when instrument cluster indicates SPI data is valid and that serial data status code bit is not set for 64 transmission cycles.

When DTC U2000 is set, fuel and temperature gauges will stay at zero and THEFT SYSTEM, ABS and SERVICE VEHICLE SOON indicators will illuminate. DTC U2000 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

With ignition switch in RUN position, check for voltage transitions on SPI data line. If only history DTC U2000 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Diagnose and repair DTC U2001 through U2007. If repair is complete, go to step 5). If repair is not complete, go to next step.
  3. Using scan tool, check DTCs. If DTC U2000 is current and DTCs U2001-U2007 are not current, go to next step. If DTC U2000 is current and DTCs U2001-U2007 are also current, go to step 2).
  4. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  5. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC U2001 indicates that BFC has detected a loss of SPI data from instrument cluster. DTC U2001 will set when Ignition 0 is active, and when all 3 data bytes received from instrument cluster are zero or do not sumcheck for 64 transmission cycles. DTC U2001 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

With ignition switch in RUN position, check for voltage transitions on SPI data line. If only history DTC U2001 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Diagnose and repair DTC U2002 through U2007. If repair is complete, go to step 5). If repair is not complete, go to next step.
  3. Using scan tool, check DTCs. If DTC U2001 is current and DTCs U2002-U2007 are not current, go to next step. If DTC U2001 is current and DTCs U2002-U2007 are also current, go to step 2).
  4. Replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article. Go to next step.
  5. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC U2002: TRANSMITTED SPI DATA INPUT LOW

Note. DTCs U2006 and U2007 must be diagnosed before DTC U2002.

DTC U2002 indicates that BFC has detected a short to ground on SPI data line from instrument cluster to BFC. DTC U2002 will set when Ignition 0 is active, and when all 3 data bytes received from instrument cluster are zero for 64 transmission cycles. DTC U2002 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

With ignition switch in RUN position, check for voltage transitions on SPI data line. If only history DTC U2002 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect instrument cluster Gray 24-pin connector. Turn ignition switch to RUN position. Using DVOM, check voltage between instrument cluster harness connector terminal A2 (Light Blue/Black wire) and ground. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 7).
  3. Using scan tool, check SPI data input. If SPI data input is HIGH, go to next step. If SPI data input is not HIGH, go to step 11).
  4. Check for a poor connection at instrument cluster harness connector terminal A2 (Light Blue/Black wire). If a poor connection exists, go to next step. If connection is okay, go to step 6).
  5. Repair poor connection at instrument cluster harness connector terminal A2 (Light Blue/Black wire). Go to step 14).
  6. Replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article. Go to step 14).
  7. Disconnect BFC Gray 24-pin connector C2. Using DVOM, check resistance between BFC harness connector C2, terminal B7 (Light Blue/Black wire) and instrument cluster harness connector terminal A2 (Light Blue/Black wire). If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 9).
  8. Check resistance between BFC harness connector C2, terminal B7 (Light Blue/Black wire) and ground. If resistance is not infinite, go to step 11). If resistance is infinite, go to step 10).
  9. Repair open in Light Blue/Black wire between BFC connector C2 and instrument cluster. Go to step 14).
  10. Repair short to ground in Light Blue/Black wire between BFC connector C2 and instrument cluster. Go to step 14).
  11. Check for a poor connection at BFC connector C2, terminal B7 (Light Blue/Black wire). If a poor connection exists, go to next step. If connection is okay, go to step 13).
  12. Repair poor connection at BFC connector C2, terminal B7 (Light Blue/Black wire). Go to step 14).
  13. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  14. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC U2003 indicates that BFC has detected a short to battery on SPI data line from instrument cluster to BFC. DTC U2003 will set when Ignition 0 is active, and when all 3 data bytes received from instrument cluster are FF for 64 transmission cycles. DTC U2003 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

With ignition switch in RUN position, check for voltage transitions on SPI data line. If only history DTC U2003 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect instrument cluster Gray 24-pin connector. Disconnect BFC Gray 24-pin connector C2. Using DVOM, check voltage between BFC harness connector C2, terminal B7 (Light Blue/Black wire) and ground. If greater than zero volts exists, go to next step. If greater than zero volts does not exist, go to step 4).
  3. Repair short to battery in Light Blue/Black wire between BFC connector C2 and instrument cluster. Go to step 11).
  4. Reconnect BFC connector C2. Connect a fused jumper wire between instrument cluster harness connector terminal A2 (Light Blue/Black wire) and ground. Using scan tool, read SPI data input feedback. If SPI data input is LOW, go to step 8). If SPI data input is not LOW, go to next step.
  5. Check for a poor connection at BFC connector C2, terminal B7 (Light Blue/Black wire). If a poor connection exists, go to next step. If connection is okay, go to step 7).
  6. Repair poor connection at BFC connector C2, terminal B7 (Light Blue/Black wire). Go to step 11).
  7. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 11).
  8. Check for a poor connection at instrument cluster connector terminal A2 (Light Blue/Black wire). If a poor connection exists, go to next step. If connection is okay, go to step 10).
  9. Repair poor connection at instrument cluster connector terminal A2 (Light Blue/Black wire). Go to step 11).
  10. Replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article. Go to next step.
  11. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC U2004: TRANSMITTED SPI DATA OUTPUT LOW

Note. DTCs U2006 and U2007 must be diagnosed before DTC U2004.

DTC U2004 indicates that BFC has detected a short to ground or open on SPI data line from instrument cluster to BFC. DTC U2004 will set when Ignition 0 is active, and when first data byte transmitted to instrument cluster does not have feedback for 64 transmission cycles.

When DTC U2004 is set, THEFT SYSTEM, ABS, and SERVICE VEHICLE SOON indicators will illuminate, fuel and temperature gauges will read zero, and PRNDL indicator will be blank. DTC U2004 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

With ignition switch in RUN position, check for voltage transitions on SPI data line. If only history DTC U2004 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect BFC Pink 24-pin connector C3. Turn ignition switch to RUN position. Using DVOM, check voltage at BFC harness connector C3, terminal A3 (Yellow wire). If battery voltage exists, go to next step. If battery voltage does not exist, go to step 6).
  3. Check for a poor connection at BFC connector C3, terminal A3 (Yellow wire). If a poor connection exists, go to next step. If connection is okay, go to step 5).
  4. Repair poor connection at BFC connector C3, terminal A3 (Yellow wire). Go to step 13).
  5. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 13).
  6. Disconnect instrument cluster Gray 24-pin connector. Using DVOM, check resistance between BFC harness connector C3, terminal A3 (Yellow wire) and instrument cluster harness connector terminal A9 (Yellow wire). If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 8).
  7. Check resistance between BFC harness connector C3, terminal A3 (Yellow wire) and ground. If resistance is infinite, go to step 10). If resistance is not infinite, go to step 9).
  8. Repair open in Yellow wire between BFC connector C3 and instrument cluster. Go to step 13).
  9. Repair short to ground in Yellow wire between BFC connector C3 and instrument cluster. Go to step 13).
  10. Check for a poor connection at instrument cluster connector terminal A9 (Yellow wire). If a poor connection exists, go to next step. If connection is okay, go to step 12).
  11. Repair poor connection at instrument cluster connector terminal A9 (Yellow wire). Go to step 13).
  12. Replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article. Go to next step.
  13. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC U2005: TRANSMITTED SPI DATA OUTPUT HIGH

Note. DTCs U2006 and U2007 must be diagnosed before DTC U2005.

DTC U2005 indicates that BFC has detected a short to battery on SPI data line from instrument cluster to BFC. DTC U2005 will set when Ignition 0 is active, and when a data byte transmitted to instrument cluster during clock idle time has feedback for 64 transmission cycles.

When DTC U2005 is set, THEFT SYSTEM, ABS, and SERVICE VEHICLE SOON indicators will illuminate, fuel and temperature gauges will read zero, PRNDL indicator will be blank and instrument cluster data output will be disabled. DTC U2004 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

With ignition switch in RUN position, check for voltage transitions on SPI data line. If only history DTC U2005 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect instrument cluster Gray 24-pin connector. Disconnect BFC Pink 24-pin connector C3. Using DVOM, check voltage between BFC harness connector C3, terminal A3 (Yellow wire) and ground. If greater than zero volts exists, go to next step. If greater than zero volts does not exist, go to step 4).
  3. Repair short to battery in Yellow wire between BFC connector C3 and instrument cluster. Go to step 11).
  4. Reconnect BFC connector C3. Using scan tool, read SPI data output line. If SPI data output is HIGH, go to step 8). If SPI data output is not HIGH, go to next step.
  5. Check for a poor connection at instrument cluster connector terminal A9 (Yellow wire). If a poor connection exists, go to next step. If connection is okay, go to step 7).
  6. Repair poor connection at instrument cluster connector terminal A9 (Yellow wire). Go to step 11).
  7. Replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article. Go to step 11).
  8. Check for a poor connection at BFC connector C3, terminal A3 (Yellow wire). If a poor connection exists, go to next step. If connection is okay, go to step 10).
  9. Repair poor connection at BFC connector C3, terminal A3 (Yellow wire). Go to step 11).
  10. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  11. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC U2006 indicates that BFC has detected a short to ground or open on SPI data line from instrument cluster to BFC. DTC U2006 will set when Ignition 0 is active, and when clock associated with first data byte transmitted to instrument cluster does not have feedback for 64 transmission cycles.

When DTC U2006 is set, THEFT SYSTEM, ABS, and SERVICE VEHICLE SOON indicators will illuminate, fuel and temperature gauges will read zero, and PRNDL indicator will be blank. DTC U2006 can be cleared using scan tool.

With ignition switch in RUN position, check for voltage transitions on SPI data line. If only history DTC U2006 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect BFC Pink 24-pin connector C3. Turn ignition switch to RUN position. Using DVOM, check voltage at BFC harness connector C3, terminal A7 (Pink/Black wire). If battery voltage exists, go to next step. If battery voltage does not exist, go to step 6).
  3. Check for a poor connection at BFC connector C3, terminal A7 (Pink/Black wire). If a poor connection exists, go to next step. If connection is okay, go to step 5).
  4. Repair poor connection at BFC connector C3, terminal A7 (Pink/Black wire). Go to step 13).
  5. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to step 13).
  6. Disconnect instrument cluster Gray 24-pin connector. Using DVOM, check resistance between BFC harness connector C3, terminal A7 (Pink/Black wire) and instrument cluster harness connector terminal A10 (Pink/Black wire). If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 8).
  7. Check resistance between BFC harness connector C3, terminal A7 (Pink/Black wire) and ground. If resistance is infinite, go to step 10). If resistance is not infinite, go to step 9).
  8. Repair open in Pink/Black wire between BFC connector C3 and instrument cluster. Go to step 13).
  9. Repair short to ground in Pink/Black wire between BFC connector C3 and instrument cluster. Go to step 13).
  10. Check for a poor connection at instrument cluster connector terminal A10 (Pink/Black wire). If a poor connection exists, go to next step. If connection is okay, go to step 12).
  11. Repair poor connection at instrument cluster connector terminal A10 (Pink/Black wire). Go to step 13).
  12. Replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article. Go to next step.
  13. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

DTC U2007 indicates that BFC has detected a short to battery on SPI data line from instrument cluster to BFC. DTC U2007 will set when Ignition 0 is active, and when a clock feedback exists during clock idle time for 64 transmission cycles.

When DTC U2007 is set, THEFT SYSTEM, ABS, and SERVICE VEHICLE SOON indicators will illuminate, fuel and temperature gauges will read zero, PRNDL indicator will be blank and instrument cluster clock output is disabled. DTC U2007 can be cleared using scan tool, or history DTC will disappear after 100 ignition cycles if fault conditions do not reoccur.

With ignition switch in RUN position, check for voltage transitions on SPI data line. If only history DTC U2007 is set, problem may be intermittent. Try to recreate fault by wiggling wiring and connectors while performing test.

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .
  2. Disconnect instrument cluster Gray 24-pin connector. Disconnect BFC Pink 24-pin connector C3. Using DVOM, check voltage between BFC harness connector C3, terminal A7 (Pink/Black wire) and ground. If greater than zero volts exists, go to next step. If greater than zero volts does not exist, go to step 4).
  3. Repair short to battery in Pink/Black wire between BFC connector C3 and instrument cluster. Go to step 11).
  4. Reconnect BFC connector C3. Using scan tool, read SPI data output line. If SPI data output is HIGH, go to step 8). If SPI data output is not HIGH, go to next step.
  5. Check for a poor connection at instrument cluster connector terminal A10 (Pink/Black wire). If a poor connection exists, go to next step. If connection is okay, go to step 7).
  6. Repair poor connection at instrument cluster connector terminal A10 (Pink/Black wire). Go to step 11).
  7. Replace instrument cluster. See «INSTRUMENT PANEL»(/chevrolet/malibu/v-1996-2000/remont/gauges-instrument-panels/#instrument-panel) article. Go to step 11).
  8. Check for a poor connection at BFC connector C3, terminal A7 (Pink/Black wire). If a poor connection exists, go to next step. If connection is okay, go to step 10).
  9. Repair poor connection at BFC connector C3, terminal A7 (Pink/Black wire). Go to step 11).
  10. Replace BFC. See «REMOVAL & INSTALLATION»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__removal-installation) . Go to next step.
  11. Clear DTCs. Perform «BFC DIAGNOSTIC SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/body-cab-control-systems/#body-control-module__bfc-diagnostic-system-check) .

BODY FUNCTION CONTROLLER (BFC)

CAUTIONBFC Pink 24-pin connector C3 contains power and ground sources. When removing BFC, always disconnect connector C3 first before disconnecting connectors C1 and C2. When installing BFC, always reconnect connectors C1 and C2, then connector C3 last.

Removal & Installation

Disconnect negative battery cable. Remove right sound insulator. Remove BFC. Disconnect BFC connectors as specified. To install, reverse removal procedure, reconnecting connectors as specified. To reprogram BFC, see REPROGRAMMING BFC .

Body Function Controller Wiring Diagram. Scheme 1

Scheme 1: Body Function Controller Wiring Diagram
Scheme 1: Body Function Controller Wiring Diagram

Data Link Connector Wiring Diagram. Scheme 2

Scheme 2: Data Link Connector Wiring Diagram
Scheme 2: Data Link Connector Wiring Diagram

Exterior Lights Wiring Diagram. Scheme 3

Scheme 3: Exterior Lights Wiring Diagram
Scheme 3: Exterior Lights Wiring Diagram

Headlight System/Daytime Running Lights Wiring Diagram. Scheme 4

Scheme 4: Headlight System/Daytime Running Lights Wiring Diagram
Scheme 4: Headlight System/Daytime Running Lights Wiring Diagram