GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2004 🢒 GTO 🢒 DTC 🢒 DTC 64

Circuit Description

The electronic brake control module (EBCM) constantly receives a throttle position (TP) sensor signal every 200 milliseconds.

Conditions for Running the DTC

DTC 64 can be set anytime the ignition switch is in the ON position.

Conditions for Setting the DTC

The EBCM does not receive a TP sensor signal for at least 6 seconds.

Action Taken When the DTC Sets
    • The EBCM disables the traction control system until the EBCM receives five consecutive messages from the TP sensor.
    • The TRAC OFF 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.

Diagnostic Aids

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:

    • An open, high resistance, or a short to ground in the ASM 5V REF circuit
    • An open or high resistance in the ASM 0V REF circuit
    • An open, high resistance or short in the ASM throttle position signal circuit
    • An internal ASM malfunction

If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The numbers below refer to step numbers on the diagnostic table.

  1. This step tests the throttle position circuits of the ASM for an open, high resistance or short.

    2.

  2. This step tests the 5V REF circuit of the ASM for an open, high resistance or short.

    3.

  3. This step tests the 0V REF circuit of the ASM for an open, high resistance or short.

Step

Action

Value(s)

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views

1

Did you perform A Diagnostic System Check - ABS?

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Go to Step 2

Go to Diagnostic System Check - ABS

2
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Use the scan tool in order to read the powertrain control module (PCM) DTCs.

Are there any PCM DTCs?

--

Go to Diagnostic Trouble Code (DTC) List in Engine Controls - 5.7L

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the accelerator and servo control module (ASM) harness connector.
  3. Disconnect the throttle position (TP) sensor connector.
  4. Disconnect the PCM harness connector.
  5. Measure the resistance of the TP signal circuits between the connectors. Refer to Circuit Testing in Wiring Systems.

Does the resistance for all circuits measure as specified?

0-5 ohms

Go to Step 4

Go to Step 6

4

Measure the resistance of the 5V REF circuit between the ASM and TP connectors. Refer to Circuit Testing in Wiring Systems.

Does the resistance measure as specified?

0-5 ohms

Go to Step 5

Go to Step 7

5

Measure the resistance of the 0V REF circuit between the ASM and TP connectors. Refer to Circuit Testing in Wiring Systems.

Does the resistance measure as specified?

0-5 ohms

Go to Step 9

Go to Step 8

6

Locate and repair the open or high resistance in the ASM TP signal circuits. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

--

7

Locate and repair the open or high resistance in the ASM 5V REF circuit. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

--

8

Locate and repair the open or high resistance in the ASM 0V REF circuit. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

--

9

Replace the Accelerator and Servo Control Module (ASM). Refer to Accelerator and Servo Control Module Replacement .

Did you complete the replacement?

--

Go to Step 10

--

10
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK