GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The torque converter clutch (TCC) Solenoid engages the lock-up clutch. The transmission control module (TCM) outputs system voltage in order to turn ON (energize) or remove voltage in order to turn OFF (to de-energize the TCC solenoid). The TCC solenoid remains OFF in the 1st and 2nd gears. The TCC remains ON in the 3rd and 4th gears when the TCM deems appropriate. The TCC solenoid can not be commanded ON when the ATF temperature is below 20°C (68°F).

Conditions for Running the DTC

    • Automatic transmission oil temperature is between 0°C (32°F) and 120°C (248°F).
    • The fault is immediately recognized with ignition ON.
    • The fault is immediately recognized after the engine starts.

Conditions for Setting the DTC

The lock-up solenoid circuit has an open or short to voltage.

Action Taken When the DTC Sets

    • The TCM illuminates the A/T warning lamp when the diagnostic runs and fails.
    • The converter clutch remains disengaged at all times.

Conditions for Clearing the MIL/DTC

The TCM turns OFF the A/T warning lamp when the diagnostic runs and does not fail.

DTC 43

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Automatic Transmission

2

  1. Ignition OFF.
  2. Disconnect TCM connector.
  3. Using DMM, measure resistance between TCM connector terminal 3 and ground.

Is the resistance within the specified value?

11-14 ohms

Go to Step 3

Go to Step 5

3

  1. Disconnect the shift solenoid connector.
  2. Using DMM, measure resistance between the shift solenoid connector terminal B4 and the TCM connector terminal 3.

Is the resistance greater than specified value?

0.3 ohms

Go to Step 6

Go to Step 4

4

Using DMM, measure voltage between the shift solenoid connector terminal B4 and ground.

Is the voltage greater than the specified value?

0 volt

Go to Step 7

Go to Step 8

5

Replace the lock-up solenoid.

Did you complete the replacement?

--

Go to Step 9

--

6

Repair an open in the lock-up solenoid circuit.

Did you complete the repair?

--

Go to Step 9

--

7

Repair a short to voltage in the lock-up solenoid circuit.

Did you complete the repair?

--

Go to Step 9

--

8

Replace the TCM. Refer to Transmission Control Module Replacement .

Did you complete the replacement?

--

Go to Step 9

--

9

  1. Clear the DTCs. Refer to Clearing Transmission Diagnostic Trouble Codes .
  2. Start the engine.
  3. Operate the vehicle within Conditions for Running the DTC.

Does the DTC reset?

--

Go to Step 2

System OK