GM Service Manual Online
For 1990-2009 cars only

Circuit Description

No engine RPM signal.

Conditions for Running the DTC

    • Automatic transmission output speed is greater than 2,000 RPM.
    • Vehicle speed is in the range of 24-91 km/h (15-57 mph).

Conditions for Setting the DTC

No engine speed signal

Action Taken When the DTC Sets

The transmission control module (TCM) illuminates the A/T warning lamp when the diagnostic runs and fails.

Conditions for Clearing the MIL/DTC

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

DTC 44

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 the transmission control module (TCM) connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Using a DMM, measure voltage between TCM connector terminal 39 and ground.

Is the voltage greater than the specified value?

10 V

Go to Step 3

Go to Step 5

3

Important: Engine running at idle speed at operating temperature.

  1. Ignition OFF.
  2. Connect a tachometer between TCM connector terminal 39 and ground.

Is the RPM within the specified value?

630-930 RPM

Go to Step 8

Go to Step 4

4

Inspect circuit for a short to voltage between the TCM connector terminal 39 and engine control module (ECM) connector terminal 48.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 5

5

Test for an open circuit between TCM connector terminal 39 and ECM connector terminal 48.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 6

6

Test circuit for a short to ground between TCM connector terminal 39 and ECM connector terminal 48.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 7

7

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

--

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