Circuit Description
The PCM supplies 5 volts on the desired torque circuit to the Electronic Brake and Traction Control Module (EBTCM). The EBTCM toggles this 5 volt signal to a ground in order to produce a duty cycle signal. The signal is proportional to the amount of engine output torque reduction requested by the EBTCM. The EBTCM supplies this signal when it detects a wheel slip. In order to reduce engine output torque, the PCM reduces the amount of spark advance and in some cases, the PCM disables a number of fuel injectors. This diagnostic tests for a Desired Torque signal failure. If the PCM does not receive the Desired torque signal, this DTC sets.
Conditions for Running the DTC
| • | The traction control has not failed. |
| • | The engine speed is greater than 500 RPM for 20 seconds. |
Conditions for Setting the DTC
The desired torque signal is not received by the PCM for 3 seconds.
Action Taken When the DTC Sets
| • | The powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | A last test failed, or the current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic. |
| • | Use a scan tool in order to clear the MIL/DTC. |
Diagnostic Aids
Important:
• Remove any debris from the PCM\TAC module connector surfaces before
servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets
when diagnosing/replacing the modules. Ensure that the gaskets are installed
correctly. The gaskets prevent contaminate intrusion into the PCM\TAC
modules. • For any test that requires probing the PCM or a component
harness connector, use the Connector Test Adapter Kit J 35616
. Using this kit prevents damage
to the harness/component terminals. Refer to
Using Connector Test Adapters
in Wiring Systems. • Do not perform this diagnostic procedure if the customer's concern
is not related to the ABS and/or the Traction Control system(s).
| • | The following may cause an intermittent: |
| - | Poor connections; Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems. |
| - | Corrosion |
| - | Mis-routed harness |
| - | Rubbed through wire insulation |
| - | Broken wire inside the insulation |
| • | For an intermittent condition, refer to Symptoms . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step determines if the EBTCM is receiving the 5 volts from the PCM. Use the connector test kit adaptor J 35616 when probing the EBTCM connector.
-
If no DTCs are set, inspect connections at the EBTCM.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
|
Important: Perform this diagnostic procedure only if the customer's concern is related to the ABS and/or the Traction Control systems. Refer to Diagnostic System Check - ABS in Antilock Brakes System.
Does the DMM display near the specified value? | 5V | |||
|
Important: Verify communication between the scan tool and the EBTCM before you continue with this diagnostic. Refer to Diagnostic System Check - ABS in Antilock Brakes System. Are any ABS/TCS/BCM DTCs set? | -- | Go to Diagnostic System Check - Body Control System in Body Control Systems or Diagnostic System Check - ABS in Antilock Brake System | Go to Diagnostic Aids | |
4 | Probe the Desired Torque circuit at the EBTCM electrical connector using the DMM J 39200 connected to ground. Refer to Probing Electrical Connectors in Wiring Systems. Does the DMM display near the specified value? | B+ | ||
5 | Probe the Desired Torque circuit at the EBTCM electrical connector using a test lamp connected to B+. Is the test lamp illuminated? | -- | ||
6 |
Did you find and correct the condition? | -- | ||
7 | Repair the short to B+ on the Desired Torque circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
8 | Repair the short to ground on the Desired Torque circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
9 |
Did you find and correct the condition? | -- | ||
10 |
Important:: Program the replacement PCM. Refer to Powertrain Control Module/Throttle Actuator Control Module Replacement . Replace the PCM. Is the action complete? | -- | -- | |
11 |
Does the scan tool indicate that this test failed? | -- | ||
12 | Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to applicable DTC | System OK |
