Diagnostic Aids

WARNING: This page is about a different car, the 2006 Buick LaCrosse and 2006 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

A poor connection at the inoperative module may cause this code to set.
An improperly powered module may cause this code to set.

DTC U0100-U0299

Step	Action	Yes	No
Schematic Reference: Data Link Connector (DLC) Schematics Connector End View Reference: Master Electrical Component List in Wiring Systems
1	Did you perform the Diagnostic System Check - Vehicle?	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	Did you record DTC U0001?	Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information	Go to Step 3
3	IMPORTANT: Use the DTC list in DTC Descriptors to determine which module is not communicating. Test the following circuits of the module that is not communicating for an open or a short to ground: The battery positive voltage input circuits The battery positive voltage output circuits The ignition voltage input circuits The ignition voltage output circuits The switched battery positive voltage circuits Refer to the following: Control Module References for the applicable schematic Circuit Testing in Wiring Systems Wiring Repairs in Wiring Systems Did you find and correct the condition?	Go to Step 8	Go to Step 4
4	Turn OFF the ignition. Test the ground circuits of the module that is not communicating for an open. If the module is the body control module (BCM), test its class 2 serial data circuit for an open, also. Refer to the following: Control Module References for the applicable schematic Circuit Testing in Wiring Systems Wiring Repairs in Wiring Systems Did you find and correct the condition?	Go to Step 8	Go to Step 5
5	Test the high speed GMLAN serial data circuits of the module that is not communicating for an open. Refer to Circuit Testing and GMLAN Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 8	Go to Step 6
6	Inspect the harness connectors of the module that is not communicating for poor connections and terminal tension at the following circuits: The battery positive voltage input circuits The battery positive voltage output circuits The ignition voltage input circuits The ignition voltage output circuits The switched battery positive voltage supply circuits The ground circuits The high speed GMLAN serial data circuits Refer to the following: Control Module References for the applicable schematic Testing for Intermittent Conditions and Poor Connections in Wiring Systems Connector Repairs in Wiring Systems Did you find and correct the condition?	Go to Step 8	Go to Step 7
7	Replace the module that is not communicating. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement?	Go to Step 8	-
8	Use the scan tool in order to clear the DTCs. Does the scan tool still display other current DTCs?	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information	-