Test Description
WARNING: This page is about a different car, the 1999 Cadillac Catera. However, it is still accessible from the selected car via links, so may be relevant.
The number(s) below refer to the step number(s) on the diagnostic table. No information has been left out.
- 2. A DTC U2100 set in either the ECM, TCM or EBTCM may have caused U2108 to set. You must diagnose and clear DTC U2100 to determine if it is the cause of U2108 setting
- 3. If the Electronic Brake Traction Control Module (EBTCM) loses power, it will cause other module(s) to set Lost Communication DTCs
- 5. The malfunction is due to an open in the CAN Bus serial data circuit or an open in the module
- 8. Because of the malfunction, the EBTCM may have set CAN Bus DTCs for those modules that it was monitoring
- 10. The Engine Control Module (ECM) and Transmission Control Module (TCM) may have set other CAN Bus DTCs because of the original malfunction. You must clear the DTCs from these modules to avoid future misdiagnosis.
DTC U2108 LOST COMM WITH ABS CONTROL SYSTEM
| Step | Action | Value(s) | Yes | No |
| 1 | Was the Data Link Communications Diagnostic System Check performed? | -- | Go to Step 2 | Diagnostic System Check - Data Link Communications |
| 2 | Was DTC U2100 recorded as a history or current DTC in the ECM, TCM or EBTCM? | -- | Go to DTC U2100 CAN-BUS Communication Malfunction and perform the diagnostics for the DTC | Go to Step 3 |
| 3 | 1. Inspect and test the EBTCM ignition feed circuit for proper voltage. 2. Inspect and test the EBTCM ground circuit. Refer to ANTI-LOCK BRAKES Schematic Did you find and correct the condition? |
-- | Go to Step 8 | Go to Step 4 |
| 4 | Inspect for poor connections/terminal tension at the CAN Bus serial data circuit(s) of the module that set DTC U2108. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS Did you find and correct the condition? |
-- | Go to Step 8 | Go to Step 5 |
| 5 | Test the CAN Bus serial data circuit(s) for an open between the module that set DTC U2108 and the EBTCM. Did you find and correct the condition? |
-- | Go to Step 8 | Go to Step 6 |
| 6 | Inspect for poor connections/terminal tension at the CAN Bus serial data circuit(s) of the EBTCM. If DTC U2108 was set in the TCM, also inspect for poor connections/terminal tension at the CAN Bus serial data circuit(s) of the ECM. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS Did you find and correct the condition? |
-- | Go to Step 8 | Go to Step 7 |
| 7 | Replace the EBTCM. Refer to Electronic Brake and Traction Control Module Replacement in Antilock Brake System.ELECTRONIC BRAKE TRACTION CONTROL MODULE (EBTCM) Did you complete the replacement? |
-- | Go to Step 10 | -- |
| 8 | 1. Install a scan tool. 2. Turn the ignition switch to the ON position, leaving the engine off. 3. Select the Display DTCs function in ABS. Does the scan tool display any DTCs other than the following? * U2103 * U2104 * U2105 * U2106 |
-- | Go to DTC INDEX | Go to Step 9 |
| 9 | Clear the DTCs using the scan tool. Did you complete the action? |
-- | Go to Step 10 | -- |
| 10 | Select the Display DTCs function for the module(s) which set DTC U2108. Does the scan tool display any DTCs other than the following? * U2103 * U2104 * U2108 |
-- | Go to DTC INDEX | Go to Step 11 |
| 11 | 1. Clear the DTCs using the scan tool. 2. Continue diagnosing or clearing the DTCs until all the modules have been diagnosed and all the DTCs have been cleared. Did you complete the action? |
-- | System OK | -- |