K 1500 Truck 4WD V8-4.8L VIN V (1999)
Body Control Module: Reading and Clearing Diagnostic Trouble Codes
With Diagnostic Scan Tool
READING DIAGNOSTIC TROUBLE CODES DTCS WITH A SCAN TOOL
The Body Control Module (BCM) is able to store DTCs in memory as a current or a history DTC. The recommended method for reading DTCs,
stored in memory, is by using a scan tool plugged into the Data Link Connector (DLC). The DLC is located under the instrument panel by the
hood release. Follow the scan tool instructions supplied by the tool manufacturer.
DIAGNOSTIC TROUBLE CODE (DTC) DIAGNOSIS
This section uses diagnostic tables, wiring diagrams and descriptive text in order to direct you in performing specific tests in order to locate and
repair the condition. The diagnostic table is a step by step procedure used in order to determine the circuit or component that is the source of the
problem. The wiring diagrams and text describing the system, test conditions, failure conditions and actions taken when a DTC is set are located
on the page facing the diagnostic table.
CURRENT CODES
When the BCM determines that a failure condition for a particular DTC is set during the current ignition cycle, the BCM sets the code as a Current
DTC. All DTCs remain current until the condition for setting the fault is corrected or the next fault free ignition cycle has occurred. The Current
code then will become a History code only.
HISTORY CODES
When a DTC is set as a current fault code the DTC will automatically be stored as a history code as well.
A history code can be cleared as follows:
^
A history DTC will clear after 100 consecutive ignition cycles without a fault present.
^
Using a scan tool.
Without Diagnostic Scan Tool
A Tech II or equivalent scan tool must be used to retrieve Diagnostic Trouble Codes (DTCs) from the PCM memory. DTCs can no longer be retrieved at
the data link connector. This also eliminates the PCM function of flashing Code 12. Follow the instructions supplied by the scan tool manufacturer in
order to access and read either current and/or history DTCs.
Clearing DTC's
IMPORTANT: The ignition switch should be in the OFF position when connecting or disconnecting the connectors to the Body Control Module (
BCM). Always disconnect the brown BCM connector first and connect the brown BCM connector last. The BCM can set DTCs with the ignition switch
in the OFF position. Disconnecting the battery or disconnecting the BCM connectors will not clear DTCs. This action may cause other DTCs to set due
to a loss of power or ground while the BCM is awake.
A DTC can not be cleared from the memory of the BCM by disconnecting the battery or by disconnecting the BCM electrical connectors. A DTC can be
cleared from the memory of the BCM by using the scan tool or after 100 concurrent ignition cycles have occurred without the fault reoccurring. Clearing
DTCs from the BCM memory is necessary after a repair has been made or to verify if a malfunction will occur again. If the fault still exists the DTC will
re-set after clearing DTCs. If any current non passlock system related DTCs exist they should be diagnosed before clearing the passlock DTCs. Clearing
the passlock DTCs will also clear all the BCM DTCs.
With Diagnostic Scan Tool
PROCEDURE
Use a Tech II or equivalent Scan tool to clear Diagnostic Trouble Codes (DTCs) from the PCM memory. When clearing DTCs, follow the
instructions supplied by the Scan tool manufacturer.
NOTES:
^
Do not clear the DTCs unless directed to do so by the service information provided for each diagnostic procedure. All of the diagnostic data
that was saved along with the DTC (freeze frame data and/or malfunction history records) which may be helpful for some diagnostic
procedures will be erased from the memory when the DTCs are cleared.
^
Interrupting PCM battery voltage to clear DTCs is NOT recommended.
Without Diagnostic Scan Tool
PROCEDURE
Use a Tech II or equivalent Scan tool to clear Diagnostic Trouble Codes (DTCs) from the PCM memory. When clearing DTCs, follow the
instructions supplied by the Scan tool manufacturer.
NOTES:
^
Do not clear the DTCs unless directed to do so by the service information provided for each diagnostic procedure. All of the diagnostic data
that was saved along with the DTC (freeze frame data and/or malfunction history records) which may be helpful for some diagnostic
procedures will be erased from the memory when the DTCs are cleared.
^
Interrupting PCM battery voltage to clear DTCs is NOT recommended.
