Colorado 2WD L4-2.8L VIN 8 (2004)
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Action Taken When the DTCs Sets
The module suspends all message transmission.
The module uses default values for all parameters received on the serial data circuits.
The module inhibits the setting of all other communication DTCs.
Conditions for Clearing the DTC
A current DTC clears when the malfunction is no longer present.
A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.
Circuit/System Verification
Refer to Data Link References to determine which serial data system is used for a specific module.
This DTC cannot be retrieved with a current status. Diagnosis is accomplished using the following symptom procedures:
Scan Tool Does Not Communicate with High Speed GMLAN Device in SI.
OR
Scan Tool Does Not Communicate with Low Speed GMLAN Device in SI.
DTC U0140 - U0184
Circuit Description
Modules connected to the GMLAN serial data circuit monitor for serial data communications during normal vehicle operation.
Operating information and commands are exchanged among the modules. In addition to this, Node Alive messages are transmitted by each module on
the GMLAN serial data circuit. When the module detects one of the following conditions on the GMLAN serial data circuit, a DTC will set.
Operating information and commands are exchanged among the modules. In addition to this, Node Alive messages are transmitted by each module on
the GMLAN serial data circuit.
Conditions for Setting the DTCs
Diagnostic algorithms are designed so that a single point failure within a particular node shall result in a single DTC/FTB combination being set. Any
recognized faults shall generate one DTC. Recognized faults may include but are not limited to the following:
^
Open or shorted condition on an I/O Circuit outside of normal operation of that circuit.
^
Erratic signal of a circuit, outside of normal operation, which can be readily and repeatedly recognized as erratic.
^
A condition, outside of normal operation, which causes a customer perception of a performance problem.
^
A condition whether hardware or data link error, which causes a device to operate in a default or fail soft mode.
^
A condition which changes or limits system performance.
^
Network supervision/signal supervision errors.
^
ECU Internal errors.
^
Criteria determined by legislation.
An initialization or shutdown self-test shall be performed and may include but is not limited to the following:
^
RAM check
^
ROM/EEPROM/Flash check