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Home >> Isuzu Truck >> 1999 >> Hombre XS Space Cab 2WD V6-4.3L >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Body Control Module >> Testing and Inspection >> Reading and Clearing Diagnostic Trouble Codes >> How to Display and Read Diagnostic Trouble Codes >> With TECH 2 >> 2. TECH 2 Description and Information >> Tech 2 Data Definitions Part 1

Tech 2 Data Definitions Part 1

Scan Tool Data Definitions
The typical scan tool readings of Body control module (BCM) data will assist in diagnosing a problem. The scan tool data displays may be viewed while the vehicle is being driven.

The typical scan tool data definitions represent general information displayed on the scan tool regarding the following items:
- BCM functions
- Ignition inputs
- Basic operating conditions

The data messages and menu headings displayed on the scan tool are defined below.


Module Information I

Module Part Number

Range: 16XXXXXX
This information refers to the part number assigned to the BCM that is currently in the vehicle.

Manufacturer Enable Counter

Range: 0 - 255
This information refers to the actual value for the manufacturers enable counter (MEC) in the BCM. This information is for the assembly plant use only.

Software Part Number

Range: 16XXXXXX
This information refers to the version of the software ID (software identification number) in the BCM.

Software Design Suffix

Range: A - Z
This information refers to the version of the software part number in the BCM.

Module Information 2

RAP Calibration Number

Range: 16XXXXXX
This information refers to the RAP calibration part number in the BCM.

RAP Suffix

Range: A - Z
This information refers to the RAP identification number in the BCM.

Lighting Calibration Number
Scan Tool Data Definitions
The typical scan tool readings of Body control module (BCM) data will assist in diagnosing a problem. The scan tool data displays may be viewed while the vehicle is being driven.

Range 16XXXXXX
This information refers to the lighting configuration calibration part number in the BCM.

Lighting Suffix

Range: AA - ZZ
This information refers to the lighting configuration identification number in the BCM.

Reminder Calibration Number

Range: 1 6XXXXXX
This information refers to the reminder warning calibration part number in the BCM.

Reminder Suffix

Range: M - ZZ
This information refers to the reminder warning identification number in the BCM.

Security Calibration Number


Range: 16XXXXXX
This information refers to the security calibration part number in the BCM.

Security Suffix

Range: M - ZZ
This information refers to the security identification number in the BCM.

Data
Dimming Potentiometer

Range: 0.0 - 18.0 volts
The voltage value displayed indicates the position of the dome lamp switch (thumb wheel). Zero (0) volts will be displayed when the following conditions exist:
- The headlamp switch is in the AUTO position.
- The daytime running lamps are OFF.

10.5 volts will be displayed when the following conditions exist:
- The park lamps or the headlamps are turned ON.
- The dome lamp switch is in the FULL bright position (thumb wheel turned completely up just before the detent).

0.1 volts will be displayed if the following conditions exist:
- The park lamps or the headlamps are turned ON.
- The dimmer switch is in the FULL DIM position (thumbwheel turned completely down).

The dimming potentiometer voltage will change as the dome lamp switch is moved between FULL BRIGHT and FULL DIM. The voltage value displayed should vary between 0.1 - 12.7 volts depending on the position of the dome lamp switch.

Battery Voltage
Range: 0 - 18.0 volts

The voltage value displayed refers to the battery system voltage measured by the BCM.

Ambient Light Sensor

Range: 0 - 5.0 volts
The displayed voltage value refers to the amount of ambient light level as measured by the light sensor. This information is used by the BCM in order to operate the automatic headlamp feature and the daytime running lamps (DRL) feature. The BCM supplies 5 volts to the ambient light p
hotocell sensor and receives a return signal voltage from the ambient light photocell on the return signal circuit. The ambient light sensor internal resistance changes with different levels of ambient light. In LIGHT ambient conditions, the resistance is low. In DARK ambient conditions, the resistance is High.

The BCM interprets the following conditions as LIGHT:
- The ambient light sensor is exposed to bright ambient light (low resistance).
- High voltage (2.2 - 4.7 volts) is present on the return circuit.

The BCM interprets the following conditions as DARK:
- The ambient light sensor is exposed to dark ambient light.
- Internal resistance increases.
- The return signal voltage decreases (0.2 - 1.3 volts).

If there is an open or a short to ground in the ambient light Sensor Circuit, the sensor will read about 0.0 volts. The BCM will default into a DARK state and turn ON the headlamps.

If the headlamps are set to the AUTO position while in the LIGHT state and the ambient light level conditions change to DARK for 15 seconds, the BCM will turn ON the headlamps.

If the headlamps are set to the AUTO position while the DARK state and the ambient light level conditions change to LIGHT for 20 seconds, the BCM will turn the headlamps OFF.

Ambient Light

Range: Light/Dark
The displayed value refers to the amount of ambient light level calculated by the BCM using the light sensor.

The information is used by the BCM for operation of the following features:
- The automatic headlamp feature
- The daytime running lamps (DRL) feature

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

The following actions will occur if there is an open or a short to ground in the ambient light sensor circuit:
- The scan tool will display DARK.
- The BCM will default into a DARK state and turn the headlamps ON.
If the head lamps are set to the AUTO position while in the LIGHT state and the ambient light level conditions change to DARK for 15 seconds, the BCM will turn the headlamps ON.

If the headlamps are set to the AUTO position while the DARK state and the ambient light level conditions change to LIGHT for 20 seconds, the BCM will turn the headlamps OFF.

Dusk

YES/NO
The displayed value refers to the dimming signal output from the BCM.This information is used by the BCM for the operation of the following features:
- Automatic headlamp
- Daytime running lamps (DRL) feature
Dusk is displayed whenever the park lamps are ON.

High Beam Input
Range: 0.0 - 18.0 Volts
The BCM uses this input in order to determine the state of the High beam headlamps. The BCM measures the circuit voltage at a point between both of the High beam headlamps and the beam selector switch. The High beam input voltage will vary depending on the state of the headlamps.




Refer to the table.

Vehicle Speed

Range: 0 - 205 km/h (0 - 127 mph)
The BCM uses the data for determining how fast the vehicle is traveling. The BCM uses this data for the operation of the following features:
- Automatic door lock feature
- Turn signal reminder feature

Inadvertent Power Timer

Range: 0 - 1216 seconds
The BCM uses this feature to protect the battery against inadvertent battery rundown caused by devices that attach to the courtesy lamp circuit. If the following lights remain ON, the BCM will turn the lights OFF after 20 minutes:
- The dome/courtesy lamp
- The vanity lamp
- The underhood or the glove box lamp

The lights are turned OFF by 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 will turn the relay OFF.

RAP Timer

Range: 0 - 1198 seconds
The BCM uses this feature to control the devices that attach to the retained accessory power (RAP) circuit. This feature allows the operation of the following components for 20 minutes after the ignition key is turned to the OFF position and before any door is opened:
- The radio
- The power windows
When any door is opened or after 20 minutes, the BCM opens the ground circuit for the RAP relay. The following components will turn OFF:
- The radio
- The power windows

The number of seconds displayed refers to the amount of time left before the BCM will turn OFF the RAP relay. The BCM uses the data in order to control the power to the RAP circuit.

Courtesy Lamp Timer

Range: 0 - 40 seconds
The BCM uses the courtesy lamp timer in order to control the devices that attach to the following circuits:
- Illuminated entry - The courtesy lamps will turn ON when you enter the vehicle. The lamps will stay ON for 15 seconds or until the ignition switch is turned to the ON position.
- Exit lighting - The courtesy lamps will turn ON when the key is removed from the ignition switch. The lamps will remain 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 I

Ignition I

Range: ACTIVE/INACTIVE
The BCM uses the Ignition 1 data in order to determine the position of the ignition switch.

ACTIVE is displayed when the ignition switch is in the RUN or CRANK position.

INACTIVE is displayed when the ignition switch is not in the RUN or CRANK position.

Ignition 3

Range: ACTIVE/INACTIVE
The BCM uses the Ignition 1 data in order to determine the position of the ignition switch.

ACTIVE is displayed when the ignition switch is in the RUN position.

INACTIVE is displayed when the ignition switch is not in the RUN position.

Ignition Power Mode

Range: OFF/RUN/CRANK/UNKNOWN
The BCM uses the ignition power mode data in order to determine the position of the ignition switch.

OFF is displayed when the ignition switch is in the OFF or the ACCESSORY positions.

RUN is displayed when the switch is in the RUN position.

CRANK is displayed when the ignition switch is in the CRANK position.

UNKNOWN is displayed when the BCM cannot determine the position of the ignition switch (i.e. between the OFF and the RUN position).

Door Handle Switch

Range: ACTIVE/INACTIVE
The door handle switch information refers to the position of either of the door handles (outside or inside). The information is used by the BCM for the illuminated entry feature.

ACTIVE is displayed when either of the handles is raised.


INACTIVE is displayed when neither of the front door handles is raised. The right front door jamb switch is also on the circuit.

ACTIVE is displayed when the right front door is opened.

INACTIVE is displayed when the right front door is completely closed.

Driver Door Jamb Switch

Range: ACTIVE/INACTIVE
The driver door jamb switch information refers to the position of the driver door.

INACTIVE is displayed when the driver door is closed and the switch plunger is pushed in.

ACTIVE is displayed when the driver door is open and the switch plunger is out.

Key In Ignition

Range: YES/NO
The key in ignition information refers to the position of the ignition key in the ignition switch.

YES displays when you completely insert the ignition key in the ignition switch cylinder.

NO displays when you do not completely insert the ignition ley into the ignition switch cylinder.

The BCM uses the data in order to control the operation of the key in ignition warning chime feature.

Seat Belt Buckled

Range: YES/NO
The seat belt buckled information refers to the position of the driver seat belt buckle.

YES displays when you buckle the driver seat belt buckle (switch opened).

NO displays when you do not buckle the driver seat belt buckle (switch closed).


The data messages and menu headings displayed on the scan tool are defined below.

The BCM uses the data in order to control the operation of the seat belt warning chime.



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