GM Service Manual Online
For 1990-2009 cars only

Module Information 1

Julian Date of Build: The scan tool displays the date upon which the Body Control Module (BCM) was manufactured.

Manufacture Enable Counter (MEC): The scan tool displays the actual value for the MEC in the BCM. This information is for the assembly plant only.

Module Part Number: The scan tool displays the part number assigned to the BCM that is currently in the vehicle.

Software Design Suffix: The scan tool displays the version of the software part number in the BCM.

Software Part Number: The scan tool displays the software identification number (ID) in the BCM.

Module Information 2

Lighting Calibration Number: The scan tool displays the lighting configuration calibration part number in the BCM.

Lighting Suffix: The scan tool displays the lighting configuration identification number in the BCM.

Reminder Calibration Number: The scan tool displays the reminder warning calibration part number in the BCM.

Reminder Suffix: The scan tool displays the reminder warning identification number in the BCM.

Retained Accessory Power (RAP) Calibration Number: The scan tool displays the RAP calibration part number in the BCM.

Retained Accessory Power (RAP) Suffix: The scan tool displays the RAP identification number in the BCM.

Security Calibration Number: The scan tool displays the security calibration part number in the BCM.

Security Suffix: The scan tool displays the security identification number in the BCM.

Data

Ambient Light: The scan tool displays LIGHT when the ambient light sensor voltage is between 2.2-4.7 volts. The scan tool displays DARK when the ambient light sensor voltage is between 0.2-1.3 volts.

Ambient Light Sensor: The scan tool displays the output voltage of the ambient light sensor based on the intensity of light detected. As the light intensity increases, the sensor displayed voltage increases. In the LIGHT state, a high voltage (2.2-4.7 volts) is present and the DRL will be ON. In the DARK state, a low voltage (0.2-1.3 volts) is present and the headlamps will be ON.

Battery Voltage: The scan tool displays the battery system voltage.

Courtesy Lamp Timer: The scan tool displays the seconds left before the BCM turns the courtesy lamp relay OFF. The BCM uses this feature to control the components attached to the illuminated entry, the remote illuminated entry and the exit lighting circuits.

Dimming Potentiometer: The scan tool displays the voltage value indicating the position of the dome lamp switch (thumbwheel). The scan tool displays 0 (zero) volts when the headlamp switch is in the AUTO position and the daytime running lamps (DRL) are ON. The scan tool displays 10.5 volts when either the park lamps or the headlamps are turned ON and the dome lamp switch is in the FULL BRIGHT position.

High Beam Input: The scan tool displays the voltage in order to determine the state of the high beam headlamps. The scan tool displays 12.2 volts with the low beams ON and 0.8 volts with the high beams ON.

Inadvertent Power Timer: The scan tool displays the seconds left before the BCM turns the inadvertent power relay OFF. The BCM uses this feature to protect the battery against inadvertent battery rundown caused by components that are part of the courtesy lamp circuit. The inadvertent power relay is supplied power by the BCM for 2400 seconds (approximately 40 minutes), after the ignition is turned OFF.

Retained Accessory Power (RAP) Timer: The scan tool displays the seconds left before the BCM turns the RAP relay OFF. The BCM uses this feature to allow the operation of the radio and the power windows for up to 1198 seconds (approximately 20 minutes), after the ignition is turned OFF. After the time has elapsed or the door is opened the BCM will open the ground circuit for the RAP relay.

Vehicle Speed: The scan tool displays the speed the vehicle is traveling. The BCM uses this data for the automatic rolling door lock and the turn signal reminder features.

Input 1

Cargo Lamp Switch: The scan tool displays the state of the switch. The scan tool displays ON when the cargo lights are requested by activation of the switch.

Door Handle Switch: The scan tool displays the position of the door handle. The scan tool displays ACTIVE when a door handle is raised and INACTIVE with all doors closed and the door handles at rest.

Door Lock Relay Feedback: The scan tool displays the state of the door lock relay. The scan tool displays ON when the BCM senses the door lock relay coil is energized.

Drivers Door Jamb Switch: The scan tool displays the position of the drivers door. The scan tool displays ACTIVE when the drivers door is open.

Horn Relay Input: The scan tool displays the state of the horn relay. The scan tool displays ACTIVE when the BCM senses that the horn relay is being commanded ON by the relay coil circuit being grounded.

Ignition 1: The scan tool displays the position of the ignition switch. The scan tool displays ACTIVE when the ignition switch is in the RUN or CRANK position.

Ignition 3: The scan tool displays the position of the ignition switch. The scan tool displays ACTIVE when the ignition switch is in the RUN position only.

Ignition Power Mode: The scan tool displays the position of the ignition switch. The scan tool displays OFF, RUN, CRANK and UNKNOWN. The UNKNOWN display is when the BCM can not determine the position of the ignition switch (between the OFF and RUN positions).

Key In Ignition: The scan tool displays the position of the ignition key in the ignition switch cylinder. The scan tool displays YES when the ignition key is fully inserted into the ignition switch cylinder. The BCM uses this data in controlling the operation of the reminder chime feature.

Last Remote Function Actuation (RFA) Command Since Wake-Up: The scan tool displays the last RFA commanded message from the BCM. The scan tool displays NONE when the BCM awakens from asleep status without receiving a RFA module request from a programmed key fob. The scan tool displays LOCK, UNLOCK or PANIC when the BCM is awake and a command is activated from the key fob to the RFA module.

Park Brake Switch: The scan tool displays the position of the park brake pedal. The scan tool displays SET when the park brake is depressed (switch closed). The BCM uses this data in controlling the operation of the park brake indicator, the reminder chime feature and the headlamp/DRL system.

Passenger Door Unlock Input: The scan tool displays the state of the passenger door unlock relay. The scan tool displays ACTIVE when the BCM senses that the passenger door unlock relay is being energized.

Remote Function Actuation (RFA) Message Since Wake-Up: The scan tool displays the last message sent to the BCM from the remote control door lock receiver.

Retained Accessory Power (RAP) Relay Feedback: The scan tool displays the state of the RAP relay. The scan tool displays ON when the BCM activates the RAP relay.

Seatbelt Buckled: The scan tool displays the position of the drivers seatbelt buckle. The scan tool displays YES when the drivers seatbelt is buckled. The BCM uses this data in controlling the operation of the seatbelt warning chime and the seatbelt indicator.

Input 2

Auto Headlamps: The scan tool displays the status of the auto headlamps. The scan tool displays ACTIVE when the auto headlamps are ON.

Cargo Lamp Switch: The scan tool displays the state of the switch. The scan tool displays ON when the cargo lights are requested by activation of the switch.

Courtesy Lamp Relay: The scan tool displays the state of the courtesy lamp relay. The scan tool displays ON when the BCM commands the courtesy lamps ON by providing a ground for the courtesy lamp relay.

Dimming Potentiometer Input: The scan tool displays the position of the dome lamp switch (thumb wheel) when the park lamps are ON. The scan tool displays ACTIVE when the dome lamp switch is in its normal position and the park lamps are ON.

Dome Lamp Switch: The scan tool displays the position of the dome lamp switch. The scan tool displays ON when the dome lamp switch is to its full up position past the detent.

Dome Override Switch: The scan tool displays the position of the dome override switch. The scan tool displays ON when the switch is activated and requesting the BCM to override the interior lighting.

Flash to Pass Switch: The scan tool displays the position of the flash to pass switch. The scan tool displays ON when the switch is pulled to activate the high beams momentarily while the switch is held.

Front Fog Lamp Switch: The scan tool displays the position of the front fog lamp switch. The scan tool displays ON when the front fog lamp switch is activated with the park lamps or headlamps ON.

Headlamp Relay Feedback: The scan tool displays the state of the headlamps. The scan tool displays ON when the headlamp and panel dimmer switch is manually turned to the ON position. The scan tool also displays ON when the switch is in the AUTO position and the ambient light sensor is in its DARK state.

High Beam Switch: The scan tool displays the position of the high beam switch. The scan tool displays ON when the high beam switch is activated.

Left Turn Signal: The scan tool displays the position of the turn signal switch. The scan tool displays ON when the left turn signal is activated. The BCM uses this data to activate the turn signal reminder chime after the vehicle has traveled 0.75 miles with the turn signal switch activated.

Park Lamps: The scan tool displays the state of the park lamps. The scan tool displays ON when the park lamps are activated by the BCM or the headlamp switch.

Right Turn Signal: The scan tool displays the position of the turn signal switch. The scan tool displays ON when the right turn signal is activated. The BCM uses this data to activate the turn signal reminder chime after the vehicle has traveled 0.75 miles with the turn signal switch activated.

Transmission Preference: The scan tool displays the position of the Tow/Haul (transmission preference) switch. The scan tool displays ON when the switch is activated. The BCM uses this data to illuminate the Tow/Haul indicator on the cluster. When activated the BCM also sends a Class 2 message to the PCM/VCM which handles the shift control.

Outputs

Chime: The scan tool displays the commanded state of the audible chime. The scan tool displays NONE when no audible chime is commanded. The scan tool displays HEAD LAMP, KEY IN IGNITION, SEAT BELT, TURN SIGNAL and PARK BRAKE as commanded.

Courtesy Lamp Relay: The scan tool displays the commanded state of the courtesy lamp relay. The scan tool displays ON when the BCM allows the courtesy lamp relay coil to go to ground to activate the courtesy lamps.

Daytime Running Lamps (DRL) Relay: The scan tool displays the commanded state of the DRL relay. The scan tool displays ON when the BCM allows the DRL relay coil to go to ground to activate the daytime running lamps.

Dimming: The scan tool displays the state of the panel dimmer switch. The scan tool displays ACTIVE when the park lamps are ON.

Door Lock Relay: The scan tool displays the commanded state of the door lock relay. The scan tool displays ON when the keyless entry transmitter LOCK button or the power lock switch is activated. The BCM allows the door lock relay coil to go to ground, locking the doors.

Driver Door Unlock Relay: The scan tool displays the commanded state of the driver door unlock relay. The scan tool displays ON when the keyless entry transmitter UNLOCK button or the power unlock switch is activated. The BCM allows the driver door unlock relay coil to go to ground, unlocking the doors.

Front Fog Lamp Relay: The scan tool displays the commanded state of the front fog lamp relay. The scan tool displays ON when the BCM allows the front fog lamp relay to go to ground to activate the front fog lamps.

Headlamp Power Relay: The scan tool displays the commanded state of the headlamp power relay. The scan tool displays ON when the BCM allows the headlamp power relay to go to ground to activate the headlamps.

Horn Relay: The scan tool displays the commanded state of the horn relay. The scan tool displays ON when the BCM allows the horn relay to go to ground to activate the horn(s). The BCM will command this state when the PANIC button on the keyless entry transmitter is activated and when there is an unauthorized entry into the vehicle.

Inadvertent Power Relay: The scan tool displays the commanded state of the inadvertent power relay. The scan tool displays ON when the BCM allows the inadvertent power relay to go to ground. The BCM allows the component of the courtesy circuit to remain on until the BCM times it off.

Interior Lighting Mode: The scan tool displays the name of the feature which commanded the interior lights on. The scan tool displays NONE when the interior lights are not commanded on. The scan tool displays INTERIOR, ILLUM. ENTRY, EXIT LIGHTING and REMOTE ILLUM. when the respective mode commands the interior lights on.

Lift Glass Relay: The scan tool displays the commanded state of the lift glass relay. The scan tool displays ON when the BCM allows the lift glass relay to go to ground opening the lift glass for the vehicles with this feature.

Park Lamp Relay: The scan tool displays the commanded state of the park lamp relay. The scan tool displays ON when the BCM allows the park lamp relay to go to ground to activate the park lamps.

Passenger Door Unlock Relay: The scan tool displays the commanded state of the passenger door unlock relay. The scan tool displays ON when the BCM allows the passenger door unlock relay to go to ground to UNLOCK the passenger door(s). The BCM will command this state when the UNLOCK button on the keyless entry transmitter is activated twice within 3 seconds.

Rear Fog Lamp Relay: The scan tool displays the commanded state of the rear fog lamp relay. The scan tool displays ON when the BCM allows the rear fog lamp relay to go to ground to activate the rear fog lamps (Export Only).

Retained Accessory Power (RAP) Relay: The scan tool displays the commanded state of the RAP relay. The scan tool displays ON when the BCM allows the RAP relay to go to ground. The BCM will allow operation of the radio and the power windows with the ignition OFF and the doors closed for up to 1198 seconds (approximately 20 minutes).

Security Data

Auto Learn Timer: The scan tool displays the seconds used by the BCM to learn valid code from the Passlock™ sensor. The learn procedure consists of 3 consecutive periods.

Battery Voltage: The scan tool displays the battery system voltage.

Content Theft Lamp: The scan tool displays the state of the SECURITY lamp. The scan tool displays ON when activated by an unauthorized entry.

Content Theft State: The scan tool displays the state of the content theft feature. The scan tool displays ALARM when activated by an unauthorized entry.

Door Key Switch: The scan tool displays the state of the door key switch. The scan tool displays ACTIVE when the switch is activated in either door key cylinder.

Ignition 1: The scan tool displays the state of the ignition switch. The scan tool displays ACTIVE when the ignition switch is in the RUN or CRANK position.

Ignition 3: The scan tool displays the state of the ignition switch. The scan tool displays ACTIVE when the ignition switch is in the RUN position.

Passlock™ Code: The scan tool displays the validity of the Passlock™ code received by the BCM. The scan tool displays OPEN, SHORTED, TAMPER and a valid code as a numeric value (1-10).

Passlock™ Data Voltage: The scan tool displays the voltage code from the Passlock™ sensor to the BCM. The BCM determines if the voltage received is a valid or invalid code voltage.

Passlock™ State: The scan tool displays the state of the Passlock™ system.

Security Lamp State: The scan tool displays the state of the SECURITY lamp. The scan tool displays ON, OFF or FLASHING.

Tamper Timer: The scan tool displays the time remaining when in the tamper mode. The timer starts when the ignition switch is turned to the RUN position and the BCM receives a Passlock™ data voltage different from the last learned voltage. The timer has a delay of 10 minutes and will stay active even if the ignition switch is cycled from the RUN to the OFF position.

VCM/PCM Fail Enable: The scan tool displays the state of the VCM/PCM fail enable mode. The scan tool displays YES when the Passlock™ system transitions from the Monitor Passlock™ Data state to the VCM/PCM Fail Enable state.

VCM/PCM Fuel Continue: The scan tool displays the state of the VCM/PCM fuel continue mode. The scan tool displays YES when the Passlock™ system verifies a valid password to the BCM.

VCM/PCM Learn Timer: The scan tool displays the state of the VCM/PCM learn timer. The scan tool displays INACTIVE when the BCM is not in a learn mode.

VTD Fuel Disable: The scan tool displays the state of the VTD fuel disable mode. The scan tool displays INACTIVE when the Passlock™ system verifies a valid password.

VTD Fuel Disable Until Ignition Off: The scan tool displays the state of the VTD fuel disable until Ignition off mode. The scan tool displays NO when the Passlock™ system verifies a valid password.

VTD Password Learn Mode: The scan tool displays the state of the VTD password learn mode. The scan tool displays INACTIVE when the Passlock™ system is not in a learn mode.