TOYOTA PRIUS 2001 Service Repair Manual

N14677
Fuse
AB0119H01300
H01301
Airbag Sensor Assembly
ON
LA
(+)
(±)
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±639
2001 PRIUS (RM778U)
Does not light up, when ignition switch is turned to ON
1 Check AM2 Fuse.
PREPARATION:
Remove the AM2 fuse.
CHECK:
Check continuity of the AM2 fuse.
OK:
Continuity
HINT:

Fuse may be burnt out even if it appears to be OK during
visual inspection.

If fuse is OK, install it.
NG Go to step 4.
OK
2 Prepare for inspection (See step 1 on page DI±629).
3 Check SRS warning light circuit.
PREPARATION:
(a) Disconnect the airbag sensor assembly connector.
(b) Connect negative (±) terminal cable to the battery.
(c) Turn the ignition switch to ON.
CHECK:
Measure the voltage between body ground and LA terminal of
the harness side connector of the airbag sensor assembly.
OK:
Voltage: 10 ± 14 V
NG Check combination meter or repair SRS warn-
ing light circuit.
OK
Replace airbag sensor assembly.

DI±640
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
2001 PRIUS (RM778U)
4 Is new AM2 fuse burnt out again?
NO Using simulation method, reproduce malfunc-
tion symptoms (See page IN±30).
YES
Check harness between AM2 fuse and SRS
warning light.

H15526
J11
J/C AW±B 2KW±BJ24
J/C
W±BDLC3
P±BJ26
J/C
P±B
Tc
8 2D 8AA
413 CGTc
E
E19
A18
Instrument Panel J/BAirbag Sensor
Assembly
ID
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±641
2001 PRIUS (RM778U)
Tc Terminal Circuit
CIRCUIT DESCRIPTION
By connecting terminals Tc and CG of the DLC3 the airbag sensor assembly is set in the DTC output mode.
The DTCs are displayed by blinking the SRS warning light.
WIRING DIAGRAM
DI6Q0±06

AB0117AB0119H15218H15700
LOCK
ON
AB0119H10688H10654
ON
CG
Tc
(+) (±)
DI±642
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
If the DTC is not displayed, do the following troubleshooting.
1 Does SRS warning light light up for approx. 6 seconds?
PREPARATION:
Check operation of the SRS warning light after ignition switch
is turned from LOCK position to ON position.
NO Check SRS warning light system (See page
DI±632).
YES
2 Check voltage between terminals Tc and CG of DLC3.
PREPARATION:
Turn the ignition switch to ON.
CHECK:
Measure the voltage between terminals Tc and CG of DLC3.
OK:
Voltage: 10 ± 14 V
OK Go to step 4.
NG

AB0119H10689H10656
ON
Tc
(+) (±)
AB0117 AB0119H01302H12918
LOCK
ON
Airbag Sensor Assembly
Tc
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±643
2001 PRIUS (RM778U)
3 Check voltage between terminal Tc of DLC3 and body ground.
CHECK:
Measure the voltage between terminal Tc of DLC3 and body
ground.
OK:
Voltage: 10 ± 14 V
OK Check harness between terminal E1 of DLC3
and body ground.
NG
4 Check airbag sensor assembly.
PREPARATION:
(a) Turn the ignition switch to LOCK.
(b) Disconnect negative (±) terminal cable from the battery,
and wait at least for 90 seconds.
(c) Disconnect the airbag sensor assembly connector.
(d) Insert service wire into terminal Tc from back side as
shown in the illustration.
(e) Connect the airbag sensor assembly connector with ser-
vice wire.
(f) Connect negative (±) terminal cable to the battery.
(g) Turn the ignition switch to ON and wait at least for 20 se-
conds.
(h) Connect service wire of terminal Tc to body ground.
CHECK:
Check operation of the SRS warning light.
OK:
SRS waning light comes on.
NOTICE:
Pay due attention to the terminal connecting position to
avoid a malfunction.
OK Check harness between the airbag sensor as-
sembly and DLC3.
NG
Replace airbag sensor assembly.

AB0119H01304H01305
LOCKAirbag Sensor Assembly
Tc
(+)
(±)
DI±644
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
2001 PRIUS (RM778U)
If the DTC is displayed without a DTC check procedure, perform the following
troubleshooting.
1 Check resistance between terminal Tc of airbag sensor assembly and body
ground.
PREPARATION:
(a) Turn the ignition switch to LOCK.
(b) Disconnect negative (±) terminal cable from the battery,
and wait at least for 90 seconds.
(c) Disconnect the airbag sensor assembly connector.
CHECK:
Check resistance between terminal Tc of the airbag sensor as-
sembly connector and body ground.
OK:
Resistance: 1 MW or Higher
NG Repair or replace harness or connector.
OK
Replace airbag sensor assembly.

DI7NG±01
N09348
Hand±held tester
Break±out±box
F12396DLC3
N17520
± DIAGNOSTICSCRUISE CONTROL SYSTEM
DI±647
2001 PRIUS (RM778U)
PRE±CHECK
1. ECU TERMINAL VALUES MEASUREMENT BY USING
BREAK±OUT±BOX AND HAND±HELD TESTER
(a) Hook up the break±out±box and hand±held tester to the
vehicle.
(b) Read the ECU input/output values by following the
prompts on the tester screen.
(c) Please refer to the hand±held tester has a ºSnapshotº
function. This records the measured data and is effective
in the diagnosis of intermittent problems.
2. USING HAND±HELD TESTER
(a) Hook up the hand±held tester to the DLC3.
(b) Monitor the ECU data by following the prompts on the tes-
ter screen.
HINT:
Hand±held tester has a ºSnapshotº function which records the
monitored data.
Please refer to the hand±held tester operator's manual for fur-
ther details.
3. DTC CLEARANCE
DTC can be deleted using a hand±held tester. If there is no
hand±held tester or it cannot be used, disconnect the auxiliary
battery for 1 min. or more and connect it again.
4. PROBLEM SYMPTOM CONFIRMATION
(ROAD TEST)
(a) Inspect the SET switch.
(1) Push the main switch ON.
(2) Drive at a desired speed (40 km/h (25 mph) or high-
er).
(3) Press the control switch to the SET/COAST.
(4) After releasing the switch, check that the vehicle
cruises at the desired speed.

N17520
N17520
N17520
DI±648
± DIAGNOSTICSCRUISE CONTROL SYSTEM
2001 PRIUS (RM778U)
(b) Inspect the ACCEL switch.
(1) Push the main switch ON.
(2) Drive at a desired speed (40 km/h (25 mph) or high-
er).
(3) Check that the vehicle speed increases while the
control switch is turned to RES/ACC, and that the
vehicle cruises at the set speed when the switch is
released.
(4) Momentarily press the control switch upward in the
RES/ACC and then immediately release it. Check
that the vehicle speed increases by about 1.5 km/h
(Tap±up function).
(c) Inspect the COAST switch.
(1) Push the main switch ON.
(2) Drive at a desired speed (40 km/h (25 mph) or high-
er).
(3) Check that the vehicle speed decreases while the
control switch is turned to SET/COAST, and the ve-
hicle cruises at the set speed when the switch is re-
leased.
(4) Momentarily press the control switch is turned to
SET/COAST, and then immediately release it.
Check that the vehicle speed decreases by about
1.5 km/h (Tap±down function).
(d) Inspect the CANCEL switch.
(1) Push the main switch ON.
(2) Drive at a desired speed (40 km/h (25 mph) or high-
er).
(3) When operating one of the followings, check that
the cruise control system is cancelled and that the
normal driving mode is reset.

Depress the brake pedal

Shift to except D range (A/T)

Push the main switch OFF

N17520
N17520
± DIAGNOSTICSCRUISE CONTROL SYSTEM
DI±649
2001 PRIUS (RM778U)

Pull the cruise control switch to CANCEL
(e) Inspect the RESUME switch.
(1) Push the main switch ON.
(2) Drive at a desired speed (40 km/h (25 mph) or high-
er).
(3) When operating one of the followings, check that
the cruise control system is cancelled and that the
normal driving mode is reset.

Depress the brake pedal

Shift to except D range (A/T)

Pull the cruise control switch to CANCEL
(4) After the control switch is turned to RES/ACC at the
driving speed of more than 40 km/h (25 mph), check
that the vehicle restores the speed prior to the can-
cellation.
5. INPUT SIGNAL CHECK
(Using hand±held tester)
(a) Connect the hand±held tester to DLC3
(b) Check the control switch (MAIN, CANCEL, SET/COAST,
RES/ACC)

DI±654
± DIAGNOSTICSCRUISE CONTROL SYSTEM
2001 PRIUS (RM778U)
CIRCUIT INSPECTION
DTC P1520 Stop light switch circuit
CIRCUIT DESCRIPTION
When the brake pedal is depressed, the stop light switch sends a signal to the hybrid vehicle control ECU.
When the hybrid vehicle control ECU receives this signal, it cancels the cruise control.
A fail±safe function is provided so that the cancel functions normally, even if there is a malfunction in the stop
light signal circuit.
The cancel condition is that battery voltage is supplied to terminal STP.
When the brake is on, battery voltage is normally applied through the STOP fuse and stop light switch to
terminal STP of the hybrid vehicle control ECU, and the hybrid vehicle control ECU turns the cruise control
OFF.
If the harness connected to terminal STP has an open circuit, terminal STP will have battery voltage and
the cruise control will be turned OFF.
DTC No.Detection ItemTrouble Area
P1520Stop light switch circuit.

Stop light switch

Harness or connector between hybrid vehicle control ECU
and stop light switch circuit

Hybrid vehicle control ECU
DI7NI±01