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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1998 🢒 Corvette 🢒 DTC 🢒 DTC U1300 Class 2 Short to Ground

Object Number: 154531 Size: LF

Circuit Description

The Class 2 serial data line allows all the modules on the line to transmit information to each other as needed. Each module is assigned an ID and all the information sent out on the line is assigned a priority by which it is received. When the ignition switch is turned to the ON position each module begins to send and receive information. Each module on the Class 2 serial data line knows what information it needs to send out and what information it should be receiving. What the modules do not know is which module is supposed to send them the information. This information is only learned after the module has received the information it needs along with the ID of the module that sent the information. This information is then remembered until the ignition switch is turned off. If the Class 2 serial data line can not communicate because the data line is shorted to ground then DTC U1300 will set.

Conditions for Setting the DTC

The EBTCM detects a short to ground on the serial data line for 5 seconds or longer. If the failure condition is present reading the DTC using the scan tool will be impossible since the scan tool uses the Class 2 data line to communicate with the EBTCM.

Action Taken When the DTC Sets

ABS remains enabled, TCS/ Active Handling™ (if equipped with RPO JL4) are disabled.

    • Indicators that turn on:
        Car Icon (TCS indicator
    • Messages displayed on the DIC:
        Service Traction System
        Service Active HNDLG (if equipped with RPO JL4)

Conditions for Clearing the DTC
    • Condition for DTC is no longer present and scan tool clear DTC function is used.
    • Fifty ignition cycles have passed with no DTCs detected.

Diagnostic Aids
    • If the problem is an intermittent loss of communications. Carefully inspect the serial data line and related components for the following intermittent conditions:
       - There is an intermittent short to ground in the serial data line.
       - Damaged or loose star connector terminals.
    • If the serial data line is shorted to ground all systems connected to the same serial data line will not be able to communicate properly.
    • If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur.

Test Description

The numbers below refer to the step numbers on the diagnostic table:

  1. This test checks if communications can be established between the scan tool and the other systems connected to the same serial data line.

    2.

  2. This test will checks for shorts in the serial data line. It also checks for any intermittent malfunctions associated with the serial data line.

DTC U1300 Class 2 Short to Ground

Step

Action

Value(s)

Yes

No

1

Was the ABS Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check

2

  1. Turn the ignition switch to the OFF position.
  2. Install a scan tool.
  3. Turn the ignition switch to the ON position, engine off.
  4. Attempt to establish communications with other systems connected to the same serial data line (PCM, BCM, IPC, etc.).

Does the scan tool communicate with other systems?

--

Go to Step 3

Go to Data Link Communications System Check in Wiring Systems

3

Check the serial data line for the following intermittent conditions:

    • Short to ground
    • Check star connector #1, and #2 make sure the bus bars are properly inserted.
    • Check for loose or damaged terminals

Was a problem found and repaired?

--

Go to Diagnostic System Check

System OK