GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 Seville 🢒 DTC 🢒 DTC P1644 Traction Control Delivered Torque Output Circuit

Object Number: 603436 Size: SF
Engine Controls Components
A/C Relay, A/C Pressure Sensor, CVRSS and EBCM
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The electronic brake and traction control module (EBCM) controls the PWM signal on the Desired Torque circuit while monitoring the wheel speed sensors to detect slippage. The PCM monitors the PWM signal and reduces engine torque as needed. The PCM sends a Delivered Torque PWM signal in response to the Desired Torque PWM signal from EBCM. If the PCM detects an improper circuit condition in the Delivered Torque circuit, DTC P1644 will set. The EBCM will disable traction control when the DTC sets. An ABS/TCS DTC may also be set. For further traction control information, refer to ABS/TCS.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC
    • An improper voltage level has been detected on the Delivered Torque Circuit.
    • The conditions exists for at least 10 seconds.

Action Taken When the DTC Sets
    • The PCM will not illuminate the malfunction indicator lamp (MIL).
    • The PCM will store the conditions present when the DTC set as Failure Records data only.

Conditions for Clearing the MIL/DTC
    • The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
    • The DTC can be cleared by using the scan tool Clear DTC Information function.

Diagnostic Aids

If the condition is intermittent, refer to Intermittent Conditions in Symptoms.

Step

Action

Values

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Turn OFF the ignition.
  2. Disconnect the EBCM.
  3. Connect test lamp between the delivered torque circuit and ground.
  4. Turn ON the ignition, with the engine OFF.

Is the test lamp ON?

--

Go to Step 3

Go to Step 4

3

  1. Turn OFF the ignition.
  2. Leave the EBCM disconnected.
  3. Disconnect the PCM connector.
  4. Turn ON the ignition, with the engine OFF.
  5. Test the delivered torque circuit for a short to voltage.
  6. If the condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 10

4

  1. Leave the EBCM disconnected.
  2. Connect test lamp between B+ and the delivered torque circuit.

Is the test lamp ON?

--

Go to Step 5

Go to Step 6

5
  1. Turn OFF the ignition.
  2. Disconnect the PCM connector.
  3. Test the delivered torque circuit for a short to ground.
  4. If the condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 10

6
  1. Turn OFF the ignition.
  2. Reconnect the EBCM connector.
  3. Disconnect the PCM connector.
  4. Turn ON the ignition, with the engine OFF.
  5. Using DMM, measure the voltage between the delivered torque circuit and ground.

Does the DMM indicate a voltage near the specified value?

B+

Go to Step 7

Go to Step 8

7
  1. Test for poor connections at the PCM.
  2. If the condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 10

8
  1. Test the delivered torque circuit for an open or poor connections at the EBCM.
  2. If the condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 9

9

Replace the EBCM. Refer to Electronic Brake Control Module Replacement in Antilock Brake System.

Is the action complete?

--

Go to Step 11

--

10

Important: The replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .

Is the action complete?

--

Go to Step 11

--

11
  1. Review and record scan tool Fail Records data.
  2. Clear DTCs.
  3. Operate the vehicle within Fail Records conditions.
  4. Using a scan tool, monitor Specific DTC info for DTC P1644 until the DTC P1644 test runs.

Does the scan tool indicate DTC P1644 passed?

--

System OK

Go to Step 2