GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 2001 🢒 Aurora 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC P1575

Circuit Description

This diagnostic test functions on the assumption that a sudden decrease in the rear, non-drive wheel speed must be caused by a brake application. The non-drive wheel speed and the stop lamp switch status are supplied to the PCM through the serial data from the electronic brake and traction control module (EBCM). If there is a 6 mph or more decrease of the non-drive wheel speed during 0.4 second and a transition of the TCC contacts at the TCC brake switch or at the stop lamp switch without a transition of the extended travel contacts of the TCC brake, DTC P1575 is set.

Conditions for Running the DTC
    •  DTC P1574 has not set.
    • The traction control and antilock brake systems have not failed.
    • The traction control and antilock brake systems are not active.
    • The non-drive wheel speed goes above 32 km/h (20 mph) and then does not go below 7 km/h (4 mph).

Conditions for Setting the DTC

A 9.6 km/h (6 mph) or more decrease in the non-drive wheel speed during 0.4 second, and a TCC brake switch or Stop/BTSI/Cruise brake switch indicating that the brakes are applied and no transition is noticed in the extended travel contacts of the TCC brake switch that indicates that the brakes are applied.

Action Taken When the DTC Sets
    • The control module stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
    • The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC
    • A current DTC Last Test Failed clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
    • Clear the DTC with a scan tool.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Turn ON the ignition, with the engine OFF.
  2. Release the brake pedal.
  3. With a scan tool, observe the Extended Travel Brake parameter.

Does the scan tool display Released?

Go to Step 3

Go to Step 5

3

Depress the brake pedal more than half-way down.

Does the scan tool display Applied?

Go to Intermittent Conditions

Go to Step 4

4

Disconnect the extended travel brake switch connector. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Does the scan tool display Applied?

Go to Step 11

Go to Step 8

5
  1. Disconnect the extended travel brake switch connector. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.
  2. Probe the ignition 1 voltage circuit with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 12

6
  1. Connect a 3 amp fused jumper wire between the signal and ignition 1 voltage circuit of the extended travel brake switch harness connector.
  2. With a scan tool, observe the extended travel brake switch parameter.

Does the scan tool display Released?

Go to Step 10

Go to Step 7

7
  1. Turn OFF the ignition.
  2. Disconnect the PCM. Refer to Powertrain Control Module Replacement .
  3. Test the signal circuit for an open circuit. Refer to Testing for Continuity in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 9

8

Test the signal circuit for a short to voltage. Refer to Testing for a Short to Voltage in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 13

9

Inspect for poor connections at the PCM.

Did you find and correct the condition?

Go to Step 15

Go to Step 13

10

Inspect for poor connections at the extended travel brake switch.

Did you find and correct the condition?

Go to Step 15

Go to Step 11

11

Test for proper TCC/extended travel brake switch adjustment. Refer to Stop Lamp Switch Adjustment in Hydraulic Brakes.

Did you find and correct the condition?

Go to Step 15

Go to Step 14

12

Test for the following circuit conditions:

    • An open in the ignition 1 voltage circuit
    • A short to ground in the ignition 1 voltage circuit
    • A short to ground in the signal circuit

Did you find and correct the condition?

Go to Step 15

--

13

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

Go to Step 15

--

14

Replace the extended travel brake switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Did you complete the replacement?

Go to Step 15

--

15
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. 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 16

Go to Step 2

16

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