GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1998 🢒 Intrigue 🢒 Body and Accessories 🢒 Body Control System 🢒 DTC U1040 Loss of ABS Class 2 Serial Data Com

Object Number: 308553 Size: SF
Handling Electrostatic Discharge Sensitive Parts Notice
Handling Electrostatic Discharge Sensitive Parts Notice
Handling Electrostatic Discharge Sensitive Parts Notice
Handling Electrostatic Discharge Sensitive Parts Notice
Handling Electrostatic Discharge Sensitive Parts Notice
Handling Electrostatic Discharge Sensitive Parts Notice
Body Control Module Components
Body Control System Schematics

Circuit Description

The BCM receives a state of health message from the Electronic Brake Traction Control Module (EBTCM) through the Class II serial data link.

Conditions for Setting the DTC

The BCM does not receive a state of health message from the EBTCM.

Action Taken When the DTC Sets
    • The BCM stores DTC U1040 in memory.
    • The ABS indicator lamp turns on while the fault is present.

Conditions for Clearing the DTC
    • DTC U1040 will clear as a current DTC U1040 and will set as a history DTC U1040 when the BCM detects a state of health message from the EBTCM.
    • A history DTC will clear after 100 consecutive ignition cycles if the condition for the fault is no longer present.
    • Using a scan tool.

Diagnostic Aids
    • The following conditions may cause an intermittent malfunction to occur:
      • An intermittent open or short to ground in circuit 1122 or 1037.
      • Poor connections at the BCM or the EBTCM.
      • An intermittent open in the Splice Pack SP205.
    • The Body Control Module (BCM) may store DTC U1040 if certain diagnostics are performed between the EBTCM and the Data Link Connector (DLC).
    • DTC P1626 will set in the Powertrain Control Module (PCM) when the ignition switch is on with the Body Control Module (BCM) disconnected. When BCM diagnostics and repairs are completed, refer to Powertrain Control Module Diagnosis in Engine Controls for additional information on PCM related DTCs.

Test Description

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

  1. This step checks for an open in the Splice Pack SP205.

    2.

  2. This step checks for a short to ground in circuit 1122.

    3.

  3. This step checks for a short to B+ in circuit 1122.

    4.

  4. This step checks for an open in circuit 1122.

    5.

  5. This step determines whether the malfunction is intermittent or the EBTCM is faulty.

Step

Action

Value(s)

Yes

No

1

Was the BCM diagnostic system check performed?

--

Go to Step 2

Go to Diagnostic System Check - Body Control System

2

  1. Turn the ignition switch off.
  2. Disconnect the scan tool from the DLC.
  3. Disconnect the battery negative terminal.
  4. Using a DMM, measure the resistance between the SP205 terminal A and each of the SP205 terminals B, E, G, L, and M; one terminal at a time.

Is the resistance measured within the specified range?

Less than 2ohms

Go to Step 3

Go to Step 7

3

  1. Disconnect the Electronic Brake Traction Control (EBTCM) connector C1.
  2. Using a DMM, measure the resistance between the SP205 harness connector terminal E and ground.

Is resistance measured same as the specified value?

∞

Go to Step 4

Go to Step 8

4

  1. Reconnect the battery negative terminal.
  2. Turn the ignition switch on.
  3. Using a DMM, measure the voltage between the SP205 harness connector terminal E and ground.

Is the voltage measured within the specified range?

Less than 2V

Go to Step 5

Go to Step 9

5

  1. Turn the ignition switch off.
  2. Using a DMM, measure the resistance between the SP205 harness connector terminal E and the EBTCM harness connector C1 terminal A1.

Is the resistance within the specified range?

Less than 2ohms

Go to Step 6

Go to Step 10

6
  1. Turn the ignition switch off.
  2. Reconnect the EBTCM connector C1.
  3. Turn the ignition switch on.
  4. Using scan tool, communicate with the EBTCM.

Does the scan tool communicate with EBTCM?

--

Go to Step 11

Go to Diagnostic System Check - ABS in Antilock Brake System

7

Replace the SP205.

Is the repair complete?

--

Go to Step 11

--

8

Repair short to ground in circuit 1122.

Is the repair complete?

--

Go to Step 11

--

9

Repair short to B+ in circuit 1122.

Is the repair complete?

--

Go to Step 11

--

10

Repair poor connection or open in circuit 1122.

Is the repair complete?

--

Go to Step 11

--

11

  1. Turn the ignition switch off.
  2. Reinstall connectors/components removed.
  3. Turn the ignition switch on.
  4. Clear BCM DTCs. Refer to Clearing DTCs for more information.
  5. Check for BCM current DTCs. Refer to Diagnostic Trouble Code (DTC) Displaying for more information.

Are there any BCM current DTCs set?

--

Go to Diagnostic System Check - Body Control System

System OK