Circuit Description
The Electronic Brake and Traction Control Module (EBTCM) 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 by retarding ignition timing, decreasing boost duty cycle, increasing air/fuel ratio, or, in severe cases, shutting OFF up to three fuel injectors. The PCM sends a PWM signal to the Electronic Brake and Traction Control Module (EBTCM) on the delivered torque circuit informing the EBTCM of response made to the desired torque signal. A problem with the delivered torque circuit should cause DTC P1689 and ABS/TCS DTC 76 to set and traction control to be disabled. Refer to ABS/TCS for further information.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
| • | An improper voltage level has been detected on the output circuit which controls the traction control delivered torque output. |
| • | The above conditions present for at least 30 seconds. |
Action Taken When the DTC Sets
| • | The PCM will not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data. |
Conditions for Clearing the MIL/DTC
| • | A 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 Info function. |
Diagnostic Aids
Check for the following conditions:
| • | Poor connection at the PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. |
| • | Damaged harness. Inspect the wiring harness for damage. |
| • | If the harness appears to be OK, disconnect the PCM, turn the ignition ON and observe a digital multimeter connected between the Traction Control Delivered Torque control circuit and ground at the PCM harness connector while moving connectors and wiring harnesses related to the EBTCM. A change in voltage will indicate the location of the malfunction. |
Reviewing the Freeze Frame/Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
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Normally, ignition feed voltage should be present on the control circuit with the PCM disconnected and the ignition turned ON.
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Tests for a shorted component or a short to B+ on the control circuit. Either condition would result in a measured current of over 500 milliamps. Also tests for a component that is going open while being operated, resulting in a measured current of 0 milliamps.
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Tests for a short to voltage on the control circuit.
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This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||
Does the voltage measure near the specified value? | B+ | |||||||||
Does the current remain within the specified range? | 0.001-0.5 Amp (1-500 mA) | |||||||||
Does the voltage measure at or near the specified value? | 0 V | |||||||||
5 | Repair short to voltage in the delivered torque control circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | -- | |||||||
6 |
Is the fuse open? | -- | ||||||||
7 |
Did you complete the repair? | -- | -- | |||||||
8 |
Does the voltage measure near the specified value? | B+ | ||||||||
9 | Test the delivered torque control circuit for an open or a short to ground. Refer to Wiring Repairs . Did you find and correct the condition? | -- | ||||||||
10 |
Did you find and correct the condition? | -- | ||||||||
11 |
Does the test lamp blink ON and OFF? | -- | Go to Diagnostic Aids | |||||||
12 | Inspect the delivered torque control circuit for a faulty connection at the PCM. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs . Did you find and correct the condition? | -- | ||||||||
13 | Repair open in ignition feed circuit to the EBTCM. Refer to Wiring Repairs . Did you complete the repair? | -- | -- | |||||||
14 | Replace the EBTCM. Refer to Electronic Brake Control Module Replacement in ABS/TCS. Did you complete the replacement? | -- | -- | |||||||
|
Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Did you complete the replacement? | -- | -- | ||||||||
16 |
Does the DTC reset? | -- | System OK |
