Toyota Tundra Service Manual: Diagnosis System

DIAGNOSIS SYSTEM

DESCRIPTION

When troubleshooting a vehicle with a diagnosis system, the only difference from the usual troubleshooting procedure is connecting the Techstream to the vehicle and reading various data output from the skid control ECU (brake actuator assembly).

The skid control ECU (brake actuator assembly) records DTCs when it detects a malfunction in itself or in its circuits.

To check for DTCs, connect the Techstream to the DLC3 on the vehicle. The Techstream can be used to clear the DTCs, activate various actuators, and check the Freeze Frame Data and Data List.

(a) Check the battery voltage.

Standard voltage:

11 to 14 V

If the voltage is below 11 V, recharge the battery before proceeding to the next step.

(b) Check the DLC3.

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DIAGNOSIS

(a) If the skid control ECU (brake actuator assembly) detects a malfunction, the ABS warning, brake warning, and/or slip indicator lights will come on in order to warn the driver.

(b) DTCs are simultaneously stored in memory.

The DTCs can be read by connecting the Techstream.

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(c) This system has a Test Mode (Signal Check) function.

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WARNING LIGHT AND INDICATOR LIGHT INITIAL CHECK

(a) When the ignition switch is turned to ON, check that the ABS warning light, brake warning light, TRAC OFF indicator light, VSC OFF indicator light, slip indicator light and AUTO LSD indicator light come on for approximately 3 seconds.

HINT:

• When the brake fluid level is low or the vacuum inside the brake booster decreases, the brake warning light comes on.
• If the warning light and indicator light check result is not normal, proceed to troubleshooting for the ABS warning, brake warning, TRAC OFF indicator, VSC OFF indicator, slip indicator and AUTO LSD indicator light circuits.
• If any of the indicators remains on or does not come on, proceed to troubleshooting for the light circuits listed below.