Scan Tool Data Definitions. GMC Truck GMC K Sierra

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC K Sierra - 4WD 🢒 Body and Accessories 🢒 Body Control System 🢒 Scan Tool Data Definitions

Typical Scan Tool Data Definitions

The typical scan tool readings of body control module (BCM) data will assist in diagnosing a problem. You can view the reading while the vehicle is being driven. The Typical Scan Tool Data Definitions represent general information displayed on the scan tool regarding, BCM functions, ignition inputs, and basic operating conditions. The data messages and menu headings displayed on the scan tool are as follows:

Scan Tool Parameter

Range

Description

Module Information 1

Module Part Number

16XXXXXX

This information refers to the part number assigned to the BCM that is currently in the vehicle.

Manufacturers Enable Counter (MEC)

0-255

This information refers to the actual value for the MEC in the BCM. This information is for the assembly plant use only.

Software Part Number

16XXXXXX

This information refers to the software identification number (ID) in the BCM.

Software Design Suffix

AA-ZZ

This information refers to the version of the software part number in the BCM.

Module Information 2

RAP Calibration Number

16XXXXXX

This information refers to the RAP calibration part number in the BCM.

RAP Suffix

AA-ZZ

This information refers to the RAP identification number in the BCM.

Lighting Calibration Number

16XXXXXX

This information refers to the lighting configuration calibration part number in the BCM.

Lighting Suffix

AA-ZZ

This information refers to the lighting configuration identification number in the BCM.

Reminder Calibration Number

16XXXXXX

This information refers to the reminder warning calibration part number in the BCM.

Reminder Suffix

AA-ZZ

This information refers to the reminder warning identification number in the BCM.

Security Calibration Number

16XXXXXX

This information refers to the security calibration part number in the BCM.

Security Suffix

AA-ZZ

This information refers to the security calibration identification number in the BCM.

Data

Dimming Potentiometer

0.0-18.0 volts

•	The voltage value displayed indicates the position of the dome lamp switch (thumb wheel).

•	Zero (0) volts will display when the headlamp switch is in the AUTO position and the daytime running lamps (DRL) are ON.

•	10.5 volts will display when either the park lamps or the headlamps are turned ON and the dome lamp switch is in the FULL BRIGHT position (thumb wheel is turned completely up just before the detent).

•	The voltage display should vary between 0.1-12.7 volts depending on the position of the dome lamp switch.

Battery Voltage

0.0-18.0 volts

The voltage value display refers to the battery system voltage.

Ambient Light Sensor

0.0-5.0 volts

The ambient light sensor is a solid state current sourcing device which varies the output current based upon the intensity of light detected. As light intensity increases, the sensor current increases.

•	The BCM supplies 5 volts to the ambient light sensor and receives a return signal voltage from the ambient light sensor on the return signal circuit.

•	In the LIGHT state, a high voltage (2.2-4.7 volts) is present on the return circuit and the DRL will be on.

•	In the DARK state, a low voltage (0.2-1.3 volts) is present on the return circuit.

•	With the headlamp switch in the AUTO position and the ambient light state changes from LIGHT to DARK, the BCM will turn the headlamps ON after a 15 second delay.

•	When the ambient light state changes from DARK to LIGHT, the BCM will turn the headlamps OFF and the DRL on after a 20 second delay.

Ambient Light

Light/Dark

•	When the ambient light sensor voltage is between 2.2-4.7 volts the LIGHT state will be displayed on the scan tool.

•	When the ambient light sensor voltage is between 0.2-1.3 volts the DARK state will be displayed on the scan tool.

High Beam Input

0.0-18.0 volts

The BCM monitors the circuit voltage in order to determine the state of the high beam headlamps. The high beam input voltages are as follows:

•	Low beams ON--12.2 volts

•	High beams ON--0.8 volts

Vehicle Speed

0-130 mph (0-209 km/h)

The BCM uses this data in order to determine how fast the vehicle is traveling. The BCM uses this data for the automatic door lock and the turn signal reminder features.

Inadvertent Power Timer

0-2400 seconds

The BCM uses this feature in order to protect the battery against inadvertent battery rundown caused by devises attached to the courtesy lamp circuit.

•	If the customer accidentally left ON the dome/courtesy vanity, the overhead reading, or the underhood or glovebox lamp, the BCM will turn the lamp OFF after approximately 40 minutes (2400 seconds).

•	The BCM turns the lamp OFF by turning OFF the inadvertent power relay. The inadvertent power relay supplies power to the courtesy lamp circuit when the ignition is in the OFF position.

The number of seconds displayed refers to the amount of time left before the BCM turns the relay OFF.

RAP Timer

0-1196 seconds

The BCM used this feature in order to control the devices attached to the retained accessory power (RAP) circuit. This feature will allow the operation of the following components for up to 20 minutes (1196 seconds) after the ignition key is turned OFF and before the door opens:

•

The radio

•	The power windows

Once any door opens or after 20 minutes (1196 seconds), the BCM opens the ground circuit for the RAP relay.

The number of seconds displayed refers to the amount of time left before the BCM will turn OFF the RAP relay.

Courtesy Lamp Timer

0-40 seconds

The BCM uses this feature in order to control the devices attached to the illuminated entry, the remote illuminated entry and the exit lighting circuits.

•	Illuminated Entry--When entering the vehicle, the courtesy lamps will come ON and stay ON for 15 seconds or until the ignition switch is turned to the RUN position.

•	Remote Illuminated Entry--When you press the key fob UNLOCK button, the courtesy lamps will come ON and stay ON for 40 seconds or until the ignition switch is turned to the RUN position.

•	Exit Lighting--When you remove the key from the ignition switch, the courtesy lamps will come ON and stay ON for 40 seconds.

The number of seconds displayed refers to the amount of time left before the BCM turns the courtesy lamp relay OFF.

Input 1

Ignition 1

•

ACTIVE

•

INACTIVE

The BCM uses this data in order to determine the position of the ignition switch. ACTIVE displays when the ignition switch is in the RUN or CRANK position.

Ignition 3

•

ACTIVE

•

INACTIVE

The BCM uses this data in order to determine the position of the ignition switch. ACTIVE displays when the ignition switch is in the RUN position only.

Ignition Power Mode

•

OFF

•

RUN

•

CRANK

•

UNKNOWN

The BCM uses this data in order to determine the position of the ignition switch. UNKNOWN displays when the BCM can not determine the position of the ignition switch (i.e. between the OFF and the RUN position).

Remote Function Actuation (RFA) Message Since Wake-Up

•

NONE

•

PANIC

•	ACTV UNLOCK Fob (#)

•

ACTV LOCK

•	PROG MODE CANCEL

•	PROG MODE REQ.

•	TRANSMITTER DIAG.

•	PROG SUCCESSFUL

•

MODE ACK

•	MANUAL RESYNC

This information refers to the last message sent to the BCM from the remote control door lock receiver (RCDLR). The RCDLR module sends a request to the BCM based on the key fob button you press. The scan tool will display the last RFA request to the BCM.

•	NONE displays when the BCM awakens from the asleep status without receiving a message from the RCDLR module.

•	ACTIVE UNLOCK FOB # displays when the button is pressed in order to UNLOCK the vehicle.

•	ACTIVE LOCK displays when a lock button is pressed to LOCK the vehicle.

•	PANIC displays when the button is pressed on the key fob.

•	MANUAL RESYNC displays any time the key fob becomes out of synchronization.

When reprogramming a key fob, the state of the RFA system will also display.

Last Remote Function Actuation (RFA) Command Since Wake-Up

•

NONE

•

LOCK

•

UNLOCK

•

REAR

•

PANIC

•	MANUAL RESYNCH

•	FOB PROGRAM

•	DIAG ACKNOWLEDGE

•	DIAG REQUEST

This information refers to the last RFA commanded message from the BCM.

•	NONE displays when the BCM awakens from the asleep status without receiving a RFA module request from a programmed key fob.

•	LOCK, UNLOCK or PANIC display when the respective LOCK, UNLOCK or PANIC button is pressed on any programmed key fob since the BCM has been awake.

Door Handle Switch

•

ACTIVE

•

INACTIVE

This information refers to the position of the door handles. The BCM uses this information for the illuminated entry feature.

•	ACTIVE displays when either door handle is raised.

•	INACTIVE displays when both doors are closed and the door handles are not raised.

Driver Door Jamb Switch

•

ACTIVE

•

INACTIVE

This information refers to the position of the drivers door.

•	INACTIVE displays when the drivers door is closed.

•	ACTIVE displays when the drivers door is open.

Passenger Door Jamb Switch

•

ACTIVE

•

INACTIVE

This information refers to the position of the passenger door.

•	ACTIVE displays when the passenger door is open.

•	INACTIVE displays when the passenger door is closed.

Key In Ignition

•

YES

•

This information refers to the position of the ignition key in the ignition switch.

•	YES displays when the ignition key is completely inserted into the ignition switch cylinder.

•	NO displays when the ignition key is not completely inserted into the ignition switch cylinder.

The BCM uses this data in controlling the operation of the warning chime features.

Seatbelt Buckled

•

YES

•

This information refers to the position of the drivers seatbelt buckle.

•	YES displays when the drivers seatbelt buckle is buckled.

•	NO displays when the drivers seatbelt buckle is not buckled.

The BCM uses this data in controlling the operation of the seatbelt warning chime and indicator.

Park Brake Switch

•

SET

•

RELEASED

This information refers to the position of the park brake pedal.

•	SET displays when the parking brake is depressed (switch closed).

•	RELEASED displays when the parking brake is not depressed (switch opened).

The BCM uses this data in controlling the operation of the park brake indicator, chime feature and the operation of the head lights/DRL system.

RAP Relay Feedback

•

OFF

This information refers to the operation of the RAP circuit.

•	ON displays whenever the BCM is turning ON the RAP relay. This action allows the operation of the radio and the power windows with the ignition switch in the OFF position and all the doors closed.

•	OFF displays when the BCM is not turning ON the RAP relay. This action does not allow the operation of the radio and the power windows with the ignition switch in the OFF position.

Passenger Door Unlock Input

•

ACTIVE

•

INACTIVE

This information refers to the operation of the passenger door unlock function and the passenger door unlock relay.

•	ACTIVE displays whenever the passenger door unlock relay coil is being energized.

•	INACTIVE displays whenever the passenger door unlock relay is not being energized.

Door Lock Relay Feedback

•

OFF

This information refers to the operation of the power door locks and the power door lock relay.

•	ON displays when the BCM senses the door lock relay coil is energized.

•	OFF displays when the door lock relay coil is not being energized

Horn Relay Input

•

ACTIVE

•

INACTIVE

This information refers to the horn operation.

•	ACTIVE displays when the BCM senses that the horn relay coil circuit is being grounded and the horns are being commanded ON.

•	INACTIVE displays when the BCM does not sense the horn relay coil circuit is being grounded.

Input 2

Headlamp Relay Feedback

•

OFF

The BCM uses this input in order to determine if the headlamps are ON or OFF.

•	ON displays when the BCM receives a voltage input on CKT 352 from the headlamp and panel dimmer switch. ON also displays when the BCM senses the ambient light sensor state is in the DARK state.

•	OFF displays when the headlamp and panel dimmer switch is in the AUTO position and the ambient light sensor is in the LIGHT state.

High Beam Switch

•

OFF

The BCM uses this input in order to determine if the high beam headlamps are ON by monitoring the voltage on CKT 524.

Park Lamps

•

OFF

The BCM monitors the voltage on the park lamp CKT 2409 in order to determine if the PARK lamps are ON.

•	ON displays when the BCM turns the park lamps ON or when the headlamp switch turns to the park lamps ON.

•	OFF displays when the park lamps are not commanded ON.

Daytime Running Lamps

•

OFF

The BCM monitors CKT 352 in order to determine if the DRL are to be commanded ON or OFF.

•	ON displays when the BCM commands the DRL ON.

•	OFF displays when the DRL are not commanded ON.

Left Turn Signal

•

OFF

The BCM uses this input in order to determine the state of the left turn signal for activation of the turn signal reminder chime.

•	ON displays when the left turn signal switch engages and illuminates the lamp.

•	OFF displays when the left turn signal switch is not engaged or the turn signal lamp is not illuminated.

Right Turn Signal

•

OFF

The BCM uses this input in order to determine the state of the right turn signal for activation of the turn signal reminder chime.

•	ON displays when the right turn signal switch engages and illuminates the lamp.

•	OFF displays when the right turn signal switch is not engaged or the turn signal lamp is not illuminated.

Front Fog Lamp Switch

•

OFF

The BCM uses this input in order to determine the status of the front fog lamp switch.

•	ON displays when the front fog lamp switch is depressed.

•	OFF displays when the front fog lamp switch is not being depressed.

Cargo Lamp Switch

•

OFF

The BCM uses this input in order to determine if the Cargo lights are being requested ON.

•	ON displays if the cargo lamp switch is closed and the BCM senses voltage low on CKT 149.

•	OFF displays when the cargo lamp switch is open and the BCM senses battery voltage on CKT 149.

Dome Lamp Switch

•

OFF

The BCM uses this input in order to determine if the dome lamp switch (thumb wheel) is requesting the interior light ON.

•	ON displays if the dome lamp switch is requesting the BCM to turn the interior lights ON (full up position past the detent).

•	OFF displays when the dome lamp switch is not requesting the BCM to turn the interior lights ON.

Dome Override Switch

•

OFF

The BCM uses this input from the dome override switch, located by the headlamp switch, in order to allow or to defeat the interior lighting when the door is open.

•	ON displays if the dome override switch is overriding the interior lighting.

•	OFF displays if the dome override switch is allowing the interior lights to turn ON when any door opens.

Dim Pot Input

•

ACTIVE

•

INACTIVE

The BCM uses this input in order to determine the position of the dome lamp switch (thumb wheel) when the park lamps are ON.

•	ACTIVE displays when the dome lamp switch is not in the FULL DOWN position and the park lamps are ON.

•	INACTIVE displays when the dome lamp switch is turned to the FULL DOWN position (dash lights OFF) and the parks lamps are ON.

Courtesy Lamp Relay

•

OFF

The BCM uses this input in order to determine the state of the courtesy lamp relay.

•	ON displays when the BCM is commanding the courtesy lamps ON by providing a ground for the courtesy lamp relay coil.

•	OFF displays when the BCM is not commanding the courtesy lamps ON.

Auto Head Lamps

•

ACTIVE

•

INACTIVE

The BCM uses this input in order to determine if the auto headlamps are ON.

•	ACTIVE displays when the auto head lamps are ON.

•	INACTIVE displays when the auto head lamps are OFF.

Outputs

Chime

•

NONE

•

HEAD LAMP

•	KEY IN IGNITION

•

SEAT BELT

•	TURN SIGNAL

This output refers to the commanded state of the audible chime.

•	NONE displays when no audible chime sound is commanded.

•	HEAD LAMP displays when the chime is commanded ON by the head lamp ON reminder feature.

•	KEY IN IGNITION displays when the chime is commanded ON by the key being in the ignition and the drivers door open.

•	SEAT BELT displays when the chime is commanded ON by the drivers seat belt is not buckled.

•	TURN SIGNAL displays when the chime is commanded ON by the BCM when on for more than 0.75 of a mile.

Interior Lighting Mode

•

NONE

•

INTERIOR

•	ILLUM. ENTRY

•	EXIT LIGHTING

•	REMOTE ILLUM.

This output displays the name of the feature which commanded the interior lights ON.

•	NONE displays when the interior lights are not commanded ON.

•	INTERIOR displays when the interior lights are commanded ON by the dome lamp switch.

•	ILLUM. ENTRY, EXIT LIGHTING and REMOTE ILLUM. display when the respective mode commands the interior lighting to turn ON.

Inadvertent Power Relay

•

OFF

This BCM output refers to the commanded state of the inadvertent power relay coil.

•	ON displays when the BCM controls the ground of the inadvertent power relay coil. This action allows the relay to power up the following components:

•	The courtesy lamp relay

•	The vanity lamps

•	The overhead reading lamps

•	The underhood lamp

•	The glove box lamp

•	OFF displays when the BCM does not ground the inadvertent power relay coil.

RAP Relay

•

OFF

This output refers to the commanded state of the RAP relay coil.

•	ON displays when the BCM controls ground of the RAP relay coil. This action allows the relay to power up the following components when the ignition switch is in the OFF position with all the doors closed:

•

The radio

•	The power windows

•	OFF displays when the BCM does not ground the RAP relay coil.

Head Lamp Power Relay

•

OFF

This output refers to the commanded state of the head lamp power relay coil.

•	On displays when the BCM controls the ground of the head lamp power relay coil.

•	OFF displays when the BCM does not ground the head lamp power relay coil.

DRL Relay

•

OFF

This output refers to the commanded state of the DRL relay coil.

•	ON displays when the BCM controls the ground of the DRL relay coil. This action allows the relay to power up the DRL.

•	OFF displays when the BCM does not control the ground of the DRL relay coil.

Park Lamp Relay

•

OFF

This output refers to the commanded state of the park lamp relay coil.

•	ON displays when the BCM controls the ground of the park lamp relay coil. This action allows the relay to power up the park lamps.

•	OFF displays when the BCM does not control the ground of the park lamp relay coil.

Front Fog Lamp Relay

•

OFF

This output refers to the commanded state of the front fog lamp relay coil.

•	ON displays when the BCM controls the ground of the front fog lamp relay coil. This action allows the relay to power up the front fog lamps.

•	OFF displays when the BCM does not control the ground of the front fog lamp relay coil.

Courtesy Lamp Relay

•

OFF

This output refers to the commanded state of the courtesy lamp relay coil.

•	On displays when the BCM controls the ground of the courtesy lamp relay coil. This action allows the relay to power up the courtesy lamps.

•	OFF displays when the BCM does not control the ground of the courtesy lamp relay coil.

Dimming

•

ACTIVE

•

INACTIVE

This output refers to the state of the head lamp switch dimming feature. The head lamp switch dimming feature gives the customer the ability to control the illumination of the instrument panel cluster, the PRNDL, the overhead console and the PSIR switch with the use of the dome lamp switch (thumb wheel) near the head lamp switch. The up and the down movement of the dome lamp switch allows the customer the ability to control the brightness of these components.

•	INACTIVE displays when the park lamps are OFF.

•	ACTIVE displays then the park lamps are ON.

Door Lock Relay

•

OFF

This output refers to the commanded state of the door lock relay coil.

•	ON displays when the BCM controls the ground of the door lock relay coil. ON is momentarily displayed when the RFA transmitter lock button is pressed or if the power lock button is pressed.

•	OFF displays when the BCM is not receiving a lock signal.

Driver Door Unlock Relay

•

OFF

This output refers to the commanded state of the driver door unlock relay coil.

•	ON displays when the BCM controls the ground of the driver door unlock relay coil. ON is momentarily displayed when the RFA transmitter unlock button is pressed or an input from the power door unlock switches. This action will cause the BCM to unlock the drivers door.

•	OFF displays when the BCM is not receiving a drivers door unlock signal.

Passenger Door Unlock Relay

•

OFF

This output refers to the commanded state of the passenger door unlock relay coil.

•	ON displays when the BCM controls the ground of the passenger door unlock relay coil. ON is displayed momentarily when the RFA transmitter unlock button is pressed twice within 3 seconds.

•	OFF displays when the BCM is not receiving a passengers door unlock signal.

Horn Relay

•

OFF

This output refers to the commanded state of the horn relay coil controlled by the BCM. The BCM will command the horns on if there is an illegal entry of the vehicle or the RFA transmitter panic button is an input to the BCM.

•	ON displays when the BCM controls the ground of the horn relay coil.

•	OFF displays when the BCM does not control the ground of the horn relay coil.