Circuit Description
The EBTCM and the PCM simultaneously controlled the traction control. The PCM sends a Requested Torque message via a pulse width modulated (PWM) signal to the EBTCM requesting the desired torque level for proper TCS operation. The EBTCM supplies the pull up voltage.
Conditions for Setting the DTC
The DTC sets if one of the following occur:
| • | An open or short in the Requested Torque line between the EBTCM and the PCM. |
| • | A TCS communication malfunction detected by the PCM and indicated to the EBTCM via a PWM message. |
Action Taken When the DTC Sets
| • | A malfunction DTC is stored. |
| • | The TCS is disabled. |
| • | The TRACTION CONTROL indicator is turned ON. |
| • | The ABS remains functional. |
Conditions for Clearing the DTC
| • | The condition for DTC is no longer present and you used scan tool Clear DTCs function. |
| • | The condition for DTC is no longer present and you used the On-Board Clear DTCs function. |
| • | The EBTCM does not detect the DTC in 50 drive cycles. |
Diagnostic Aids
| • | It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction. |
| • | An intermittent malfunction can be caused by poor connections, broken insulation, or a wire that is broken inside the insulation. |
| • | If an intermittent malfunction exists, refer to Intermittents and Poor Connections Diagnosis in Wiring Systems. |
| • | The following conditions can cause this concern: |
| - | An open circuit. |
| - | An short to ground or voltage in the circuit. |
| - | A wiring problem, terminal corrosion, or poor connection in the circuit. |
| - | A communication frequency problem. |
| - | A communication duty cycle problem. |
| - | The EBTCM is not receiving information from the PCM. |
Test Description
The numbers below refer to step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check | ||||
2 | Check the following grounds, making sure each ground is clean and torqued to the proper specifications:
Were any loose, damaged, or corroded grounds found? | -- | Go to Step 3 | Go to Step 4 | ||||
3 | Repair the ground as necessary. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Diagnostic System Check | -- | ||||
Is the duty cycle within the specified range? | 85-95% | Go to Step 5 | Go to Step 6 | |||||
Is the frequency within the specified range? | 121-134 Hz | Go to Step 13 | Go to Step 7 | |||||
6 |
Is the voltage within the specified range? | 4.5-5.5 V | Go to Step 7 | Go to Step 8 | ||||
7 | Replace the EBTCM. Refer to Electronic Brake Control Module Replacement . Did you complete the repair? | -- | Go to Diagnostic System Check | -- | ||||
8 |
Is the voltage greater than the specified value? | 1 V | Go to Step 9 | Go to Step 10 | ||||
9 | Repair the short to voltage in CKT 463. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Diagnostic System Check | -- | ||||
10 |
Is the resistance within the specified range? | OL (infinite) | Go to Step 12 | Go to Step 11 | ||||
11 | Repair the short to ground in CKT 463. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Diagnostic System Check | -- | ||||
12 | Using a J 39200 DMM, measure the resistance between the J 39700 terminal 25 and the PCM connector C2 terminal 46. Is the resistance less than the specified value? | 2 ohms | Go to Step 13 | Go to Step 14 | ||||
13 | Suspect PCM. Refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 4.6L. Is the diagnosis complete? | -- | Go to Diagnostic System Check | -- | ||||
14 | Repair the open in CKT 463. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Diagnostic System Check | -- |
