ESP TOYOTA CAMRY 1999 Service Owners Manual

ABS (TMC MADE)
This system controls the respective brake fluid pressures acting on the disc brake cylinders of the right front wheel, left front
wheel and rear wheels when the brakes are applied in a panic stop so that the wheels do not lock. This results in improved
directional stability and steerability during panic braking.
1. INPUT SIGNALS
(1) Speed sensor signal
The speed of the wheels is detected and input to TERMINALS FL+, FR+, RL+ and RR+ of the ABS ECU.
(2) Stop light SW signal
A signal is input to TERMINAL STP of the ABS ECU when the brake pedal is depressed.
2. SYSTEM OPERATION
During sudden braking the ABS ECU has signals input from each sensor, which controls the current to the solenoid inside
the actuator and lets the hydraulic pressure acting on each wheel cylinder escape to the reservoir. The pump inside the
actuator is also operating at this time and it returns the brake fluid from the reservoir to the master cylinder, thus preventing
locking of the vehicle wheels.
If the ABS ECU judges that the hydraulic pressure acting on the wheel cylinder is insufficient, the current on the solenoid is
controlled and the hydraulic pressure is increased. Holding of the hydraulic pressure is also controlled by the ABS ECU, by
the same method as above. Pressure reduction, holding and increase are repeated to maintain vehicle stability and to
improve steerability during sudden braking.
A9, A10 ABS SPEED SENSOR FRONT LH, RH
2±1 :0.6 kW±2.5 kW
A25, A26 ABS SPEED SENSOR REAR LH, RH
2±1 :1.2 kW±2.3 kW
A18 (A), A19 (B) ABS ECU
(Connect the ABS ECU connectors)
(B)21±GROUND : Approx. 12 volts with the ignition SW at ON position and the data link connector 1
TS±E1, TC±E1 not connected
(B) 8±GROUND : Approx. 12 volts with the ignition SW at ON position and the data link connector 1
TS±E1, TC±E1 not connected
(B)13±GROUND : Approx. 12 volts with the ignition SW at ON position
(B) 5±GROUND : Approx. 12 volts with the brake pedal depressed
(B)12, (B) 25±GROUND :
Always continuity
: PARTS LOCATION
CodeSee PageCodeSee PageCodeSee Page
A4A26 (1MZ±FE)A2532J1131A4A28 (5S±FE)A2632J1231
A5B26 (1MZ±FE)C1030J2231A5B28 (5S±FE)D126 (1MZ±FE)J2331
A926 (1MZ±FE)D128 (5S±FE)J27A31A928 (5S±FE)D430J28B31
A1026 (1MZ±FE)J331J2931A1028 (5S±FE)J431S631
A18A30J7A31
A19B30J8B31
: RELAY BLOCKS
CodeSee PageRelay Blocks (Relay Block Location)
325Engine Room R/B No.3 (Radiator Upper Support RH)
SYSTEM OUTLINE
SERVICE HINTS

ABS (TMMK MADE)
This system controls the respective brake fluid pressures acting on the disc brake cylinders of the right front wheel, left front
wheel and rear wheels when the brakes are applied in a panic stop so that the wheels do not lock. This results in improved
directional stability and steerability during panic braking.
1. INPUT SIGNALS
(1) Speed sensor signal
The speed of the wheels is detected and input to TERMINALS FL+, FR+, RL+ and RR+ of the ABS actuator and ECU.
(2) Stop light SW signal
A signal is input to TERMINAL STP of the ABS actuator and ECU when the brake pedal is depressed.
2. SYSTEM OPERATION
During sudden braking the ABS actuator and ECU has signals input from each sensor, which controls the current to the
solenoid inside the actuator and lets the hydraulic pressure acting on each wheel cylinder escape to the reservoir. The pump
inside the actuator is also operating at this time and it returns the brake fluid from the reservoir to the master cylinder, thus
preventing locking of the vehicle wheels.
If the ABS actuator and ECU judges that the hydraulic pressure acting on the wheel cylinder is insufficient, the current on the
solenoid is controlled and the hydraulic pressure is increased. Holding of the hydraulic pressure is also controlled by the
ABS actuator and ECU, by the same method as above. Pressure reduction, holding and increase are repeated to maintain
vehicle stability and to improve steerability during sudden braking.
A9, A10 ABS SPEED SENSOR FRONT LH, RH
2±1 : Approx. 1.6 kW
A25, A26 ABS SPEED SENSOR REAR LH, RH
2±1 : Approx. 1.6 kW
A6 ABS ACTUATOR AND ECU
(Connect the ABS actuator and ECU connectors)
12±GROUND : Approx. 12 volts with the ignition SW at ON position and the data link connector 1
TS±E1, TC±E1 not connected
11±GROUND : Approx. 12 volts with the ignition SW at ON position and the data link connector 1
TS±E1, TC±E1 not connected
16, 19±GROUND : Always continuity
15±GROUND : Approx. 12 volts with the ignition SW at ON position
14±GROUND : Approx. 12 volts with the brake pedal depressed
17, 18±GROUND : Always approx. 12 volts
: PARTS LOCATION
CodeSee PageCodeSee PageCodeSee Page
A626 (1MZ±FE)C1030J1231A628 (5S±FE)D126 (1MZ±FE)J2231
A926 (1MZ±FE)D128 (5S±FE)J2331A928 (5S±FE)D430J27A31
A1026 (1MZ±FE)J331J28B31A1028 (5S±FE)J431J2931
A2532J7A31S631
A2632J8B31
: RELAY BLOCKS
CodeSee PageRelay Blocks (Relay Block Location)
325Fusible Link Block (Radiator Upper Support RH)
SYSTEM OUTLINE
SERVICE HINTS