GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1998 🢒 Regal 🢒 DTC 🢒 DTC C1344 Left TCS Channel Does Not Move

Object Number: 247770 Size: MF
ABS Components
Antilock Brake System Schematics
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

DTC C1344 detects a stuck TCS motor or a seized hydraulic modulator. During initialization or after a TCS cycle, the EBCM/EBTCM commands the TCS motor in the reverse direction and the forward direction to ensure that the motor moves properly. If the TCS motor does not move, the EBCM/EBTCM detects improper current feedback. A DTC will then set.

Conditions for Setting the DTC

DTC C1344 will set during initialization or after a TCS cycle.

A malfunction exists if the EBCM/EBTCM detects a condition in which the EBCM/EBTCM cannot move the motor in either direction.

Action Taken When the DTC Sets
    • A malfunction DTC stores.
    • The TCS disables.
    • The amber TCS indicator turns on.
    • The red BRAKE warning indicator turns on.

Conditions for Clearing the DTC
    • The condition responsible for setting the DTC no longer exists and the Scan Tool Clear DTCs function is used.
    • 100 drive cycles pass with no DTC(s) detected.

Diagnostic Aids

An intermittent malfunction in DTC C1344 may be caused by one of the following conditions in a mechanical part of the system:

    • Sticking
    • Binding
    • Slipping

Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction. Refer to the Scan Tool manual for the procedure.

Thoroughly inspect any circuitry that may cause the intermittent complaint for the following conditions:

    • Backed out terminals
    • Improper mating
    • Broken locks
    • Improperly formed or damaged terminals
    • Poor terminal-to-wiring connections
    • Physical damage to the wiring harness

Step

Action

Value(s)

Yes

No

1

Was the Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check

2

Visually inspect the following components for proper wire color/connector cavity combination:

    • The 4-way TCS motor pack connector
    • The 8-way EBCM/EBTCM connector C3

Are the proper wires located in the proper connector cavities?

--

Go to Step 3

Go to Step 11

3
  1. Raise the vehicle until the drive wheels are positioned 15 cm (six inches) off the floor.

    2. Support the vehicle.

    Refer to Vehicle Lifting and Jacking in General Information.

  2. Turn the ignition switch to the RUN position.

    3. Do not start the engine.

  3. Pump the brake pedal until the pedal is firm in order to deplete the brake booster vacuum reservoir.
  4. Install a Scan Tool .
  5. Select Special Functions on the Scan Tool .
  6. Select the Manual Control Function on the Scan Tool .
  7. Verify that there is no downward pressure on the brake pedal.
  8. Select the left front TCS Motor Release Function on the Scan Tool .
  9. Use the Scan Tool in order to release the left front TCS motor.
  10. Attempt to hand rotate the left front wheel.

Does the left front wheel rotate?

--

Go to Step 4

Go to Step 5

4
  1. Verify that there is no downward pressure on the brake pedal.
  2. Select the Motor Apply function on the Scan Tool .
  3. Select the left front TCS Motor function on the Scan Tool .
  4. Attempt to hand rotate the left front wheel.

Does the left front wheel rotate?

--

Go to Step 5

Go to Step 17

5
  1. Verify that there is no downward pressure on the brake pedal.
  2. Select the left front TCS Motor Release function on the Scan Tool .
  3. Use the Scan Tool in order to release the left front TCS motor while carefully observing the following currents:
    4. • The left front TCS motor commanded current
    • The left front TCS motor feedback current

Was the left front TCS motor feedback current equal to or less than the specified current?

8A

Go to Step 10

Go to Step 6

6
  1. Exit the Scan Tool Manual Control function on the Scan Tool .
  2. Turn the ignition switch to the OFF position.
  3. Disconnect the 4-way TCS motor pack connector.
  4. Disconnect the 8-way EBCM/EBTCM connector C3.
  5. Use the J 39200 in order to measure the resistance between the following components:
    6. • The 8-way EBCM/EBTCM harness connector C3 terminal G
    • The 8-way EBCM/EBTCM harness connector C3 terminal H.

Is the resistance within the specified range?

OL

(Infinite)

Go to Step 7

Go to Step 12

7

Use the J 39200 in order to measure the resistance between the following components:

    • The 4-way TCS motor pack connector terminal A
    • The 4-way TCS motor pack connector terminal B.

Is the resistance equal to or greater than the specified resistance?

0.2 ohms

Go to Step 8

Go to Step 13

8
  1. Inspect the following components for poor terminal contact or corrosion:
  2. the 4-way TCS motor pack connector
  3. The 4-way TCS motor pack harness connector
  4. The 8-way EBCM/EBTCM connector C3
  5. The 8-way EBCM/EBTCM harness connector C3

Do any of the terminals exhibit poor terminal contact or corrosion?

--

Go to Step 15

Go to Step 9

9
  1. Turn the ignition switch to the OFF position.
  2. Reconnect the 8-way EBCM/EBTCM connector C3.
  3. Reconnect the 4-way TCS motor pack connector.
  4. Start the engine with your foot off the brake pedal.
  5. Test drive the vehicle at a speed of at least 16 km/h (10 mph).
  6. Stop the vehicle and turn the ignition switch to the OFF position.
  7. Repeat the above drive cycle sequence two more times.
  8. Use the Scan Tool in order to inspect for DTCs.

Does DTC C1344 set during the last three drive cycles?

--

Go to Step 16

Go to Step 17

10
  1. Turn the ignition switch to the OFF position.
  2. Remove the TCS modulator/motor pack assembly from the vehicle. Refer to On Vehicle Service in Antilock Brakes.
  3. Separate the TCS motor pack from the TCS modulator.
  4. Grasp the gear on the TCS modulator and attempt to rotate the gear.

    5. The hydraulic modulator gear is the furthest rearward gear when the TCS modulator is installed in the vehicle.

Can the hydraulic modulator gear be rotated at least seven full revolutions from lock to lock?

--

Go to Step 13

Go to Step 14

11
  1. Disconnect the 4-way TCS motor pack connector.
  2. Disconnect the 8-way EBCM/EBTCM connector C3.
  3. Use the circuit diagram in order to place the proper wires into the proper connector cavities.

Is the repair complete?

--

Go to Step 9

--

12

Repair the short between CKT 564 and CKT 565.

Is the repair complete?

--

Go to Diagnostic System Check

--

13

Replace the TCS motor pack.

Is the repair complete?

--

Go to Diagnostic System Check

--

14

Replace the TCS modulator.

Is the repair complete?

--

Go to Diagnostic System Check

--

15

Replace the terminals that exhibit the following conditions:

    • Poor terminal contact
    • Terminal corrosion

Is the repair complete?

--

Go to Diagnostic System Check

--

16

Replace the EBCM/EBTCM.

Is the repair complete?

--

Go to Diagnostic System Check

--

17

The malfunction is intermittent or is not present at this time.

Is the repair complete?

--

Go to Diagnostic Aids

--