Symptom Chart D (TCS Operational Check, No Codes Set)

Symptom Chart D:

Symptom Chart D Wiring Schematic:

TEST DESCRIPTION
Test numbers refer to circled numbers on the diagnostic chart.

1. Traction control system should interpret the elevated front wheels as an icy or free spin condition. At 1/2 throttle a properly operating system will allow both front wheels to spin up quickly to about 20 - 25 MPH and then slow down (but not stop) to about 5-10 MPH and have a jerky appearance. The traction control "ACTIVE" message should display on the DIC. The pump motor should also be heard.

2. System is building up pressure to the front brake and operating correctly.

3. System is not building up pressure to the front brakes. Possible air or dirt in the system.

4. No dirt in reservoir and the fluid level is OK. Air may still be trapped in system. The TCS hydraulic circuit should be bled using TECH 1 TCS test and bleed procedure. One of the front caliper bleed screws must be open to allow air to escape.

5. Fluid level OK. Air may still be trapped in the system. The TCS hydraulic circuit should be able using TECH 1 TCS test and bleed procedure. One of the front caliper bleed screws must be open to allow air to escape.

6. Reservoir TCS prime pipe may be contaminated. Flush pipe and reservoir to remove any debris. Air may still be trapped in system. The TCS hydraulic circuit should be bled using TECH 1 TCS test and bleed procedure. One of the front caliper bleed screws must be open to allow air to escape.

DIAGNOSTIC AIDS
The Brake Light Switch must be properly adjusted to prevent an erroneous brake application input to the EBTCM/EBCM. Misadjustment may prevent brake intervention during traction control operation. Also, the EBTCM/EBCM receives TCC switch status over serial data from the PCM. If serial data is lost or the switch remains engaged, brake intervention during traction control may be lost. Monitor PCM TCC switch input P171 while cycling brake switch. The input should cycle "HI" and "LO".

The PCM shall not allow traction control fuel shutoff if:
^ Engine Coolant Temperature less than -40° C (-40° F).
^ Engine Coolant Temperature greater than or equal to 131° C (268° F).
^ Low Coolant Level Detected.

Cylinders shall be disabled if the engine speed greater than or equal to 600 RPM.

The PCM can disable traction control for up to 11 ignition cycles if override PS24, Traction Control Disable, is activated; When PS24 is selected, the display will alternate between "- -" for one second and the current state of Traction Control Disable override ("99" for override active and "00" for override not active). Pressing the WARMER button will disable traction control for the next eleven ignition cycles and display "99". The "TRACTION DISABLED" message will be displayed for the duration of this override and no TCS diagnostic trouble codes will be set. Pressing the COOLER button will allow normal program control of traction control and display "00".