TOYOTA PRIUS 2001 Service Repair Manual

H04504H01062H08346
Airbag
Sensor
Assembly
Front Airbag
Sensor (LH)
(+) +SL
(±)±SL
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±629
2001 PRIUS (RM778U)
6 Check front airbag sensor (LH).
CHECK:
For the connector (on the front airbag sensor (LH)), measure
the resistance between +SL and ±SL.
OK:
Resistance: 300 ± 1500 W
NG Replace front airbag sensor (LH).
OK

H02757
AB0119
H10600H01064H10647
Front Airbag
Sensor (LH)
Airbag
Sensor
Assembly
ON
DTC B1158/B1159/16
DLC3
CG
Tc
"u "u
DI±630
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
2001 PRIUS (RM778U)
7 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) Connect the front airbag sensor (LH) connector and air-
bag sensor assembly connector.
(d) Connect negative (±) terminal cable to the battery, and
wait at least for 2 seconds.
CHECK:
(a) Turn the ignition switch to ON, and wait at least for 20 se-
conds.
(b) Clear the DTC stored in memory (See page DI±497).
(c) Turn the ignition switch to LOCK, and wait at least for 20
seconds.
(d) Turn the ignition switch to ON, and wait at least for 20 se-
conds.
(e) Check the DTC (See page DI±497).
OK:
DTC B1158/B1159/16 is not output.
HINT:
Codes other than code B1158/B1159/16 may be output at this
time, but they are not relevant to this check.
NG Replace airbag sensor assembly.
OK
From the results of the above inspection, the malfunctioning part can now be considered normal.
To make sure of this, use the simulation method to check.

H03354H16253H16297
Airbag
Sensor
Assembly Front Airbag
Sensor (LH)
(+)
+SL
(±)
±SL
ON
Engine Room Main
Wire Harness
u"
H03354H16252H16298
Airbag
Sensor
Assembly Front Airbag
Sensor (LH)
(+)+SL
(±)±SL Engine Room Main
Wire Harness
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±631
2001 PRIUS (RM778U)
8 Check engine room main wire harness (to B+).
PREPARATION:
Disconnect the engine room main wire harness connector on
the airbag sensor assembly side.
CHECK:
(a) Turn the ignition switch to ON.
(b) For the connector (on the LH front door wire harness side)
between the airbag sensor assembly and the engine
room main wire harness, measure the voltage between
body ground and each of +SL and ±SL.
OK:
Voltage: Below 1 V
NG Repair or replace engine room main wire har-
ness.
OK
Repair or replace harness or connector between airbag sensor assembly and engine room main
wire harness.
9 Check engine room main wire harness (to ground).
PREPARATION:
Disconnect the engine room main wire harness connector on
the airbag sensor assembly side.
CHECK:
For the connector (on the engine room main wire harness side)
between the airbag sensor assembly and the engine room main
wire harness, measure the resistance between body ground
and each of +SL and ±SL.
OK:
Resistance: 1 MW or Higher
NG Repair or replace engine room main wire har-
ness.
OK
Repair or replace harness or connector between airbag sensor assembly and engine room main
wire harness.

H03354H16251H16299
Airbag
Sensor
Assembly
Front Airbag
Sensor (LH)
(±) +SL
±SL
Engine Room Main
Wire Harness
(+)
u "
DI±632
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
2001 PRIUS (RM778U)
10 Check engine room main wire harness.
PREPARATION:
Disconnect the engine room main wire harness connector on
the airbag sensor assembly side.
CHECK:
For the connector (on the engine room main wire harness side)
between the airbag sensor assembly and the engine room main
wire harness, measure the resistance between +SL and ±SL.
OK:
Resistance: 1 MW or Higher
NG Repair or replace engine room main wire har-
ness.
OK
Repair or replace harness or connector between airbag sensor assembly and engine room main
wire harness.

H03352H16251H03360H16300
Airbag
Sensor
Assembly Front Airbag
Sensor (LH)
(+) +SL
(±)±SL
Engine Room Main
Wire Harness
+SL
±SL
u "
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±633
2001 PRIUS (RM778U)
11 Check engine room main wire harness.
PREPARATION:
(a) Disconnect the engine room main wire harness connector
on the airbag sensor assembly side.
(b) Using a service wire, connect +SL and ±SL of the connec-
tor (on the engine room main wire harness side) between
the engine room main wire harness and the front airbag
sensor (LH).
CHECK:
For the connector (on the engine room main wire harness side)
between the airbag sensor assembly and the engine room main
wire harness, measure the resistance between +SL and ±SL.
OK:
Resistance: Below 1 W
NG Repair or replace engine room main wire har-
ness.
OK
Repair or replace harness or connector between airbag sensor assembly and engine room main
wire harness.

H15524
B±W
W5
2BB±O
GR
W±B ACC Relay 10A SRS ACC
5A AM1
FL Block No. 2 FL Block No. 1 15A AM2
Battery 100A
DC/DCB±G W±RA
J11
J/C W±G
W±R P±L1
2H
8
2C2
2E
4
2E
8
2K
2B 536
A18ACC
120A
1 1
F13 1
F12
1
F11 1B9 2
1J B1
2G2
2C ACC
2
67AM1
AM2 IG2MAIN
35
A18IG2 Airbag Sensor
Assembly Instrument Panel J/B
Ignition Switch
ID 12
3
Instrument Panel J/B Engine Room J/B DI±634
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
2001 PRIUS (RM778U)
DTC Normal Source Voltage Drop
CIRCUIT DESCRIPTION
The SRS is equipped with a voltage±increase circuit (DC±DC converter) in the airbag sensor assembly in
case the source voltage drops.
When the battery voltage drops, the voltage±increase circuit (DC±DC converter) functions to increase the
voltage of the SRS to normal voltage.
The diagnosis system malfunction display for this circuit is different from other circuits that is when the SRS
warning light remains lit up and the DTC is a normal code, source voltage drop is indicated.
Malfunction in this circuit is not recorded in the airbag sensor assembly, and the source voltage returns to
normal, the SRS warning light automatically goes off.
DTC No.Diagnosis
(Normal)Source voltage drop
WIRING DIAGRAM
DI6PY±07

H01026H06508H06509
LOCKAirbag
Sensor
Assembly
P/T Squib (LH)
Side Airbag
Sensor (LH)
Side Squib
(LH)P Squib
D Squib
Spiral
Cable
Front Airbag
Sensor (RH) Front Airbag
Sensor (LH)
P/T Squib (RH)
Side Airbag
Sensor (RH)
Side Squib
(RH)
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±635
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Prepare for inspection.
PREPARATION:
(a) Disconnect negative (±) terminal cable from the battery,
and wait at least for 90 seconds.
(b) Remove the steering wheel pad (See page SR±6).
(c) Disconnect the connector of the front passenger airbag
assembly (See page RS±27).
(d) Disconnect the connector of the side airbag assembly RH
and LH (See page RS±40).
(e) Disconnect the connector of the seat belt pretensioner
RH and LH (See page BO±90).
(f) Disconnect the connectors of the airbag sensor assembly
(See page RS±52).
(g) Disconnect the connector of the front airbag sensor RH
and LH (See page RS±57).
(h) Disconnect the connector of the side airbag sensor as-
sembly RH and LH (See page RS±62).
CAUTION:
Store the steering wheel pad, front passenger airbag as-
sembly and side airbag assemlby with the front surface
facing upward.

AB0119H01298H01299
Airbag Sensor Assembly
ON
IG1
ACC
(+) (±)
H01249
ON
DI±636
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
2001 PRIUS (RM778U)
2 Check source voltage.
PREPARATION:
Connect negative (±) terminal cable to the battery.
CHECK:
(a) Turn ignition switch ON.
(b) Measure the voltage between body ground and each of
IG1 and IG2 on the sensor and operate electric system
(defogger, wiper, headlight, heater blower, etc.).
OK:
Voltage: 10 ± 14 V
NG Check harness between battery and airbag sen-
sor assembly, and check battery and charging
system.
OK
3 Does SRS warning light turn off?
PREPARATION:
(a) Turn the ignition switch to LOCK.
(b) Connect the steering wheel pad connector.
(c) Connect the front passenger airbag assembly connector.
(d) Connect the side airbag assembly connectors.
(e) Connect the seat belt pretensioner connectors.
(f) Connect the airbag sensor assembly connectors.
(g) Connect the front airbag sensor connectors.
(h) Connect the side airbag sensor assembly connectors.
(i) Turn the ignition switch to ON.
CHECK:
Operate electric system (defogger, wiper, headlight, heater
blower, etc.) and check that SRS warning light goes off.
NO Check for DTCs. If a DTC is output, perform trou-
bleshooting for the DTC. If a normal code is out-
put, replace airbag sensor assembly.
YES
From the results of the above inspection, the malfunctioning part can now be considered normal.
To make sure of this, use the simulation method to check.

H15525
Combination Meter
Instrument Panel J/B
10A ACC
ACC Relay
5A AM1
W±G L15
C10
16
C10
5
C11
GR±RGR±R
W±BB±Y 9
2A
2
2D
8
2A
1
2H
8
2C
3
2B53
128
2K4
2B 1
2E3
A18LA
1
F11C
J27
Fl Block No. 1
23P±LW 1
F13
1 B±GL
GR±R
BBC
J28AB
A
J11
J/C
Battery F18
FL
Block
No. 2DLC3
DC/DC100A
J/C
I15 Ignition S/W
120A
MAINAirbag Sensor
Assembly
B±Y6
ID J26
J/C
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±637
2001 PRIUS (RM778U)
SRS Warning Light Circuit Malfunction
CIRCUIT DESCRIPTION
The SRS warning light is located on the combination meter.
When the SRS is normal, the SRS warning light lights up for approx. 6 seconds after the ignition switch is
turned from the LOCK position to ON position, and then turns off automatically.
If there is a malfunction in the SRS, the SRS warning light lights up to inform the driver of the abnormality.
When terminals Tc and CG of the DLC3 are connected, the DTC is displayed by blinking the SRS warning
light.
WIRING DIAGRAM
DI7QT±01

AB0117H01293H01295
Airbag Sensor Assembly
LOCK
DI±638
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
Always lights up, when ignition switch is in LOCK position
1 Prepare for inspection (See step 1 on page DI±629).
2 Does SRS warning light turn off?
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) Connect negative (±) terminal cable to the battery.
CHECK:
Check operation of SRS warning light.
NO Check SRS warning light circuit or terminal A/B
circuit of DLC3.
YES
Replace airbag sensor assembly.