Hombre S Regular Cab 4WD V6-4.3L (1999)
16. This step determines if the BCM power CKT-41 is open between the BCM and the CRUISE fuse.
Description of On-Board Diagnostics
Diagnostic Information
Use the Diagnostic Trouble Code (DTC) tables. in order to locate a faulty circuit or a component through the process of elimination. The BCM performs
a continual self-diagnosis on certain control functions. A DTC sets when a malfunction is detected by the BCM. The BCM will not turn the SERVICE
ENGINE SOON malfunction indicator lamp (MIL) to the ON position.
Class 2 Serial Data Communication
The Class 2 network continually monitors various subsystems (i.e. ATC, BCM, HVAC, IPC, PCM, and VCM) and operating conditions for possible
system malfunctions. Compare the system conditions against standard operating limits in order to detect certain circuit and component malfunctions. A
5-digit alphanumeric diagnostic trouble code (DTC) is stored in the computer memory. When a malfunction is detected by this self-diagnostic system,
the DTC(s) may later be retrieved by the service technician using a scan tool. The scan tool may aid the technician in repairing various subsystems.
Data Link Connector (DLC)
The 16-pin DLC is wired to the Body control module. The 16-pin DLC is located under the dash panel on the left side. The DLC connector has terminals
that are used in order to connect to a scan tool. The following list shows some common uses of the scan tool:
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Identifying stored diagnostic trouble codes (DTCs)
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Clearing DTCs
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Performing output control tests
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Reading serial data
Scan Tool Diagnosis
Use the scan too in order to monitor the communications between the BCM and the PCM/VCM. The scan tool also displays Passlock (TM) data. The
Passlock (TM) data list display is located under the PASSLOCK selection. This list shows the status of the hardwired connections from the Passlock
(TM) sensor to the BCM. These scan tool values may be very useful in diagnosing the Passlock (TM) system.
The Passlock (TM) system is designed in order to deter theft, even if various parts are changed. The following components may not be changed without
the possibility of entering into no-start condition:
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The Passlock (TM) sensor
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The powertrain control module (PCM)
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The Body control module (BCM)
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The vehicle control module (VCM)
The BCM and the PCM/VCM require the full 10 minutes in order to complete a lockout cycle. The ignition key MUST remain in the RUN position until
the telltale turns to the OFF position. If the ignition key is turned from the RUN position before the telltale turns to the OFF position, you will have to
repeat the lockout cycle. The Passlock (TM) system requires 3 consecutive lockout cycles in order to complete the 30 minute learn procedure for a
changed component.
Scan Tool Information Modes
On the scan tool, four modes are available in the Body control module selection. Select the following items:
1. Body control module
2. Data display
3. Data list
The following list appears on the scan tool:
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Data
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Input 1
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Input 2
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Outputs
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Security data
The scan tool allows for the for the display of Class 2 values, or the state of components commanded by the various systems (i.e. ATC, BCM, HVAC,
IPC, PCM and VCM). The tests available are dependent upon the system selected, but may include the following modes:
Data (analog inputs): This test displays analog values as seen by the system.
Inputs (digital inputs): This test displays digital values as seen by the system and provides an indication of whether the input has cycled.
Outputs (digital outputs): This test allows for digital outputs controlled by the BCM system in order to be turned OFF/ON.
