GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The transmission control module (TCM) receives the throttle position from the engine control module (ECM). This data is part of the pulse width modulated (PWM) ECM data signal to the TCM. This signal processes in the TCM. Several parameter values that are contained within the PWM signal separate out. If the entire PWM signal is not present due to a circuit problem, DTC 54 is set. If the TCM receives the signal, but the TCM determines that the throttle position (TP) value is invalid, this DTC will set.

Conditions for Running the DTC

    • System operating voltage between 9-18 volts.
    • Engine at operating temperature.

Conditions for Setting the DTC

    • The control unit recognizes no PWM signal.
        OR
    • The voltage level of the PWM signal is "low" (OV) for less than 0.15 ms for longer than 9.3 ms.
    • Above condition must be fulfilled for at least 4 seconds.

Action Taken When the DTC Sets

    • The TCM illuminates the A/T warning lamp when the diagnostic runs and fails.
    • Gear change control is set to full throttle.
    • Line pressure control is set to full throttle.
    • Torque converter clutch (TCC) is disabled.

Conditions for Clearing the MIL/DTC

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

DTC 54

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. Install a scan tool.
  2. Turn the ignition ON with the engine OFF.
  3. Record the DTC Failure Records.

Did you record any engine control module (ECM) DTC Failure Records?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 3

3

  1. Ignition OFF.
  2. Do not disconnect transmission control module (TCM) connector.
  3. Turn ON the ignition, with engine OFF.
  4. Using a DMM, measure voltage between the TCM connector terminal 46 and ground.

Is the voltage less than the specified value?

1.5 V

Go to Step 4

Go to Step 9

4

  1. Ignition OFF.
  2. Disconnect the TCM connector.
  3. Using DMM, measure the duty cycle between the TCM connector terminal 46 and ground.
  4. Turn ON the ignition, with the engine OFF.
  5. Engine running at idle speed at operating temperature.
  6. Acceleration pedal not actuated.

Is the percentage within the specified value?

8-16%

Go to Step 5

Go to Step 8

5

Accelerator pedal briefly actuated to a full load stop.

Is the percentage within the specified value?

75-82%

Go to Step 6

Go to Step 7

6

Replace the TCM. Refer to Transmission Control Module Replacement .

Did you complete the replacement?

--

Go to Step 10

--

7

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

--

Go to Step 10

--

8

Inspect circuit for a short to ground/interruption between the TCM connector terminal 46 and ECM connector terminal 41.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 7

9

Inspect circuit for a short to voltage between the TCM connector terminal 46 and ECM connector terminal 41.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 7

10

  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