DTC P1644 Traction Control Delivered Torque Output Circuit. Cadillac Eldorado 2000

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2000 🢒 Eldorado 🢒 Engine 🢒 Engine Controls - 4.6L 🢒 DTC P1644 Traction Control Delivered Torque Output Circuit

Engine Controls Component Views
EBCM, Generator, A/C Relay and RSS
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 powertrain control module (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 switch 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

Value(s)

Yes

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

Go to Step 2

Go to the Powertrain On Board Diagnostic (OBD) System Check

Turn OFF the ignition.
Disconnect the PCM.
Turn ON the ignition, with the engine OFF.
With the DMM J 39200 , measure voltage between the delivered torque control circuit at the PCM connector and ground.

Is voltage near the specified value?

B+

Go to Step 3

Go to Step 5

With the DMM J 39200 measure the current between the delivered torque control circuit at the PCM harness connector and ground.
Monitor the current reading on the digital multimeter for at least 2 minutes.

Does the current reading remain between the specified values?

0.001-0.5 Amp

(1-500 mA)

Go to Step 6

Go to Step 4

Turn OFF the ignition.
Disconnect the EBCM (leave the PCM disconnected).
Turn ON the ignition, with the engine OFF.
Test the delivered torque circuit for a short to voltage.
If a condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Electronic Brake Control Module Replacement in Antilock Brake System

Turn OFF the ignition.
Test the delivered torque circuit for the following conditions:

•

An open

•	A short to ground

•	Poor connections at the EBCM

If a condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Diagnostic System Check - ABS in Antilock Brake System

Inspect the delivered torque control circuit for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
If a condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 7

Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .

Replace the PCM.

Is action complete?

Go to Step 8

Review and record scan tool Fail Records data.
Clear DTCs.
Operate the vehicle within Fail Records conditions.
With a scan tool, monitor Specific DTC info for DTC P1644 until the test runs.

Does the scan tool indicate DTC P1644 passed?

System OK

Go to Step 2