P1689

Schematic:

CIRCUIT DESCRIPTION

The Electronic Brake And Traction Control Module (EBTCM) controls the Pulse Width Modulated (PWM) signal on the desired torque circuit while monitoring the wheel speed sensors to detect slippage. The PCM monitors the PWM signal and reduces the engine torque as needed by retarding the ignition timing, decreasing the boost duty cycle, increasing the air/fuel ratio, or, in severe cases, shutting OFF up to 3 fuel injectors. The PCM sends a PWM signal to the 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 to set and the traction control to be disabled. An ABS/TCS DTC may also be set.

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 for the traction control delivered torque output circuit.
^ The above conditions are present for a minimum of 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 a scan tool.

DIAGNOSTIC AIDS
Check for the following conditions:
^ A faulty connection at the PCM-Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections. Use a corresponding mating terminal to test for proper terminal tension.
^ 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 the connectors and wiring harnesses related to the EBTCM. A change in voltage will indicate the location of the malfunction. Refer to Wiring Repairs in Diagrams.

Reviewing the Failure 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

Steps 1 - 8:

Steps 9 - 16:

The numbers below refer to the step numbers on the diagnostic table.
2. The ignition feed voltage should normally be present on the control circuit with the PCM disconnected and the ignition turned ON.
3. Checks for a shorted component or a short to B+ on the control circuit. Either condition would result in a measured current of more than 500 milliamps. Also checks for a component that is going open while operating, resulting in a measured current of 0 milliamps.
4. Checks for a short to voltage on the control circuit.
15. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read-only Memory (EEPROM). When the PCM is replaced, the new PCM must be programmed.