GM Service Manual Online
For 1990-2009 cars only

Object Number: 174451  Size: MF
ABS Components
Antilock Brake System Schematics

Circuit Description

The solenoid valves are supplied voltage from the MaxiFuse® through the valve relay to operate. The EBTCM monitors the valve feed circuit to determine if a valve response to an EBTCM activation request is detected. The valve relay is an integral part of the EBTCM and cannot be replaced individually.

Conditions for Setting the DTC

    • 2 or more valves do not respond to an EBTCM request.
    • The EBTCM senses a discrepancy such as an open or a short to ground in the circuit.

Action Taken When the DTC Sets

    • A malfunction DTC is stored.
    • The ABS and the TC indicator lamps are turned on.
    • The ABS and the TCS are disabled.

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present.
    • The scan tool Clear DTCs function is used.
    • 100 drive cycles have passed with no DTCs detected.

Diagnostic Aids

Perform a thorough inspection of the wiring. Perform a thorough inspection of the connectors. Failure to carefully and fully inspect the wiring and the connectors may result in misdiagnosis. Misdiagnosis causes part replacement with reappearance of the malfunction.

Test Description

The number(s) below refer to the step numbers on the diagnostic table.

  1. This step checks for a short to ground on the EBTCM side of the fuse. Check both fuse block terminals to verify. The fuse terminals are not identified.

  2. This step checks if the fuse opens when the ignition switch is turned to the RUN position, and the ABS/TCS performs the self test during the test drive.

  3. This step determines if a short to ground in the BPMV is causing the open fuse. If the BPMV checks ok, the short is in the EBTCM.

DTC 19 - Valve Relay Circuit Malfunction

Step

Action

Value(s)

Yes

No

Important: Perform the following checks before testing:

   • Check that the battery is fully charged.
   • Check that the charging system is operating properly.

1

Was the Diagnostic System Check performed?

--

Go to Step 2

Go to A Diagnostic System Check

2

  1. Turn the ignition switch to the OFF position.
  2. Remove the 80 amp power distribution MaxiFuse® V4.
  3. Inspect the 80 amp power distribution MaxiFuse® V4.

Is the fuse open?

--

Go to Step 3

Go to Step 4

3

Use a J 39200 DMM to measure the resistance between both of the power distribution fuse block terminals of fuse V4 and ground.

Is the resistance within the specified range on either terminal?

OL (Infinite)

Go to Step 7

Go to Step 6

4

  1. Disconnect the 4-pin EBTCM connector C2 from the EBTCM.
  2. Inspect the 4-pin EBTCM connector C2 terminal 2 for the following signs:
  3. • Inspect for signs of damage.
    • Inspect for signs of poor terminal contact.
    • Inspect for signs of terminal corrosion.
  4. Inspect the remaining terminals of the 4-pin EBTCM connector C2 for the following signs:
  5. • Inspect for signs of damage.
    • Inspect for signs of poor terminal contact.
    • Inspect for terminal corrosion.

Are the following signs evident:

    • Is poor terminal contact evident?
    • Is corrosion evident?
    • Is damage evident?

--

Go to Step 14

Go to Step 5

5

  1. Reinstall the MaxiFuse®.
  2. Use a J 39200 DMM to measure the voltage between the 4-pin EBTCM harness connector C2 terminal 2 and ground.

Is the voltage within the specified range?

Battery Voltage

Go to Step 9

Go to Step 12

6

  1. Disconnect the 4-pin EBTCM connector C2 from the EBTCM.
  2. Use a J 39200 DMM to measure the resistance between the 4-pin EBTCM harness connector C2 terminal 2 and ground.

Is the resistance within the specified range?

OL (Infinite)

Go to Step 10

Go to Step 13

7

  1. Install a new MaxiFuse®.
  2. Test drive the vehicle above 6 km/h (3.5 mph).
  3. Turn the ignition switch to the OFF position.
  4. Recheck the MaxiFuse®.

Is the fuse open?

--

Go to Step 8

Go to A Diagnostic System Check

8

  1. Disconnect the 6-pin solenoid valve connector from the EBTCM.
  2. Use a J 39200 DMM to measure the resistance between the 6-pin solenoid valve harness connector terminal 2 and the BPMV case.
  3. Use a J 39200 DMM to measure the resistance between the 6-pin solenoid valve harness connector terminal 2 and terminals 4 and 6.

Is the resistance within the specified range with all measurements?

OL (Infinite)

Go to Step 10

Go to Step 11

9

  1. Reconnect the 4-pin EBTCM connector C2.
  2. Turn the ignition switch to the OFF position.
  3. Disconnect the scan tool if previously connected.
  4. Test drive the vehicle above 6 km/h (3.5 mph).

Did DTC 19 reset?

--

Go to Step 10

Go to A Diagnostic System Check

10

Replace the EBTCM. Refer to EBTCM Replacement .

Is the repair complete?

--

Go to A Diagnostic System Check

--

11

Replace the BPMV. Refer to Brake Pressure Modulator Valve (BPMV) Replacement

Is the repair complete?

--

Go to A Diagnostic System Check

--

12

Repair an open in CKT A290. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to A Diagnostic System Check

--

13

Repair a short to ground in CKT A290. . Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to A Diagnostic System Check

--

14

Repair the 4-pin EBTCM connector C2. Refer to Connector Repairs in Wiring Systems.

Is the repair complete?

--

Go to A Diagnostic System Check

--