Diagnostic Aids

WARNING: This page is about a different variant/trim than selected.

The TCM scan tool data parameters that are received from the ECM, will indicate zero when the CAN serial data circuit failure is active.
An intermittent malfunction may be caused by a fault in the electrical circuit. Inspect the wiring harness and the components for an intermittent condition. Refer to Intermittent Conditions in Engine Controls 1.6L.
Repair any electrical circuit faults that were found. Refer to Wiring Repairs in Wiring Systems.
The information included in the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC first set.

DTC U2105 (European and N. American Emissions)

Step	Action	Values	Yes	No
Schematic Reference: Automatic Transmission Controls Schematics Connector End View Reference: Connector End Views
1	Did you perform the Diagnostic System Check - Transmission/Transaxle?	-	Go to Step 2	Go to Diagnostic System Check - Automatic Transmission
2	Install a scan tool. Turn ON the ignition, with the engine OFF. Save the DTC and Freeze Frame information into the scan tool memory. Perform the scan tool Clear DTC Information function for the TCM and the ECM. Operate the vehicle for 1 minute or until the MIL illuminates. Check the TCM for DTCs. Is DTC U2105 displayed?	-	Go to Step 3	Go to Diagnostic Aids
3	Turn OFF the ignition. Disconnect connector A from the transmission control module (TCM). Turn the ignition ON, with the engine OFF. Measure the voltage between the CAN Serial Data High circuit at the connector and ground. Measure the voltage between the CAN Serial Data Low circuit at the connector and ground. Was the voltage within the specified values for both the high and the low CAN circuits?	1.5-3.4 V	Go to Step 6	Go to Step 4
4	Inspect the CAN serial data circuit with the incorrect voltage for the following: Open circuit Short to ground Short to voltage Repair as necessary. Refer to Wiring Repairs and Connector Repairs in Wiring Systems. Did you find and correct a condition?	-	Go to Step 9	Go to Step 5
5	Inspect for poor connections at the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct a condition?	-	Go to Step 9	Go to Step 8
6	Inspect for poor connections at the harness connector of the TCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct a condition?	-	Go to Step 9	Go to Step 7
7	Replace the TCM. Refer to Transmission Control Module (TCM) Replacement . Did you complete the replacement	-	Go to Step 9	-
8	Replace the ECM. Refer to Engine Control Module (ECM) Replacement in Engine Controls 1.6L. Did you complete the replacement?	-	Go to Step 9	-
9	Use the scan tool in order to clear the DTCs. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC run and pass?	-	Go to Step 10	Go to Step 2
10	With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed?	-	Go to Diagnostic Trouble Code (DTC) List	System OK