Lexus SC300 / Lexus SC400. Manual - part 278

DTC

62

TRAC Vehicle Speed Malfunction

CIRCUIT DESCRIPTION

DTC No.

DTC Detecting Condition

Trouble Area

62

Detection of any of conditions (1) through (3):

At vehicle speed of 10 km/h (6 mph) or more, pulses

are not input for 5 sec.

ECU

HINT: When DTC Nos. 31–36 are recorded in memory, DTC No. 62 is not recorded.

DIAGNOSTIC CHART

DIAGNOSTIC CHART

BR–140

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

–MEMO–

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

BR–141

BE–78

).

BR–74

).

IN–33

).

WIRING DIAGRAM

Stop Light Switch Circuit

CIRCUIT DESCRIPTION

The stop light switch senses whether the brake pedal is depressed or released, and sends a signal to the ECU.

DIAGNOSTIC CHART

DIAGNOSTIC CHART

BR–142

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

OK

NG

NG

OK

OK

NG

INSPECTION PROCEDURE

1

Check operation of stop light.

Check that stop light lights up when brake pedal is depressed and turns off when brake pedal is re-
leased.

C

Repair stop light circuit (See page 

BE–78

).

2

Check voltage between terminal STP of ABS (& TRAC) ECU and body ground.

C

OK

P

Remove ABS (& TRAC) ECU with connectors still con-
nected.

Measure voltage between terminal STP of ABS (&
TRAC) ECU and body ground when brake pedal is de-
pressed.

Voltage:

8 – 14 V

Proceed to next circuit inspection shown on problem
symptoms chart (See page 

BR–74

).

3

Check for open in harness and connector between ABS (& TRAC) ECU and stop light switch
(See page 

IN–33

).

Repair or replace harness or connector.

Check and replace ABS (& TRAC) ECU.

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

BR–143