TOYOTA PRIUS 2001 Service Repair Manual

± DIAGNOSTICSELECTRIC MOTOR POWER STEERING
DI±495
2001 PRIUS (RM778U)
4 Check battery positive voltage.
PREPARATION:
Start the engine.
CHECK:
Check the battery positive voltage.
OK:
Voltage: 9 ± 14 V
NG Check and repair charging system.
OK
5 Check operation of PS warning light.
PREPARATION:
(a) Turn the ignition switch OFF.
(b) Disconnect the connector from the EMPS ECU.
(c) Turn the ignition switch ON.
CHECK:
Check the PS warning light goes OFF.
OK Check and replace EMPS ECU.
NG
Check for short circuit in harness and connector between multiinformation display and EMPS
ECU, multiinformation display and DLC3 (See page IN±41).

F12842
EMPS ECU
Tc
E63
P±B
C CJ16
J/C
P±B 2
ID1 P±B
E EJ26
J/C
P±B 13
Tc
5
SGBR14
ID2BR
BR 14
IO1
EB DLC3 DI±496
± DIAGNOSTICSELECTRIC MOTOR POWER STEERING
2001 PRIUS (RM778U)
Tc Terminal Circuit
CIRCUIT DESCRIPTION
Connecting terminals Tc and CG of the DLC3 causes the EMPS ECU to display the DTC by flashing the PS
warning light.
WIRING DIAGRAM
DI7RE±01

F09678
ON
Tc
CG
± DIAGNOSTICSELECTRIC MOTOR POWER STEERING
DI±497
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminals Tc and CG of DLC3.
CHECK:
Turn the ignition switch ON and measure the voltage between
terminals Tc and CG of the DLC3.
OK:
Voltage: 9 ± 14 V
OK If PS warning light does not blink even after Tc
and CG are connected, EMPS ECU may be de-
fective.
NG
2 Turn the ignition switch OFF, and check for open and short circuit in harness
and connector between EMPS ECU and DLC3, and DLC3 and body ground (See
page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace EMPS ECU.

F12844
EMPS ECU
Ts
E69
B BJ16
J/C
3
ID1 GR±G
14
Ts
5
SGBR14
ID2BR
BR 14
IO1
EB DLC3
GR±G GR±G DI±498
± DIAGNOSTICSELECTRIC MOTOR POWER STEERING
2001 PRIUS (RM778U)
Ts Terminal Circuit
CIRCUIT DESCRIPTION
The sensor check circuit detects abnormalities in the speed sensor signal which cannot be detected by the
DTC check.
Connecting terminals Ts and CG of the DLC3 starts the check.
WIRING DIAGRAM
DI7RF±01

F09679
ON
Ts
CG
± DIAGNOSTICSELECTRIC MOTOR POWER STEERING
DI±499
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminals Ts and CG of DLC3.
CHECK:
Turn the ignition switch ON and measure the voltage between
terminals Ts and CG of the DLC3.
OK:
Voltage: 9 ± 14 V
OK If PS warning light repeats turning ON and OFF
even after Ts and CG are connected, EMPS ECU
may be defective.
NG
2 Turn the ignition switch OFF, and check for open and short circuit in harness
and connector between EMPS ECU and DLC3, DLC3 and body ground (See page
IN±41).
NG Repair or replace harness or connector.
OK
Check and replace EMPS ECU.

DI6OY±07
H15218
H10658
DLC3
CG Tc
DI±502
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
2001 PRIUS (RM778U)
PRE±CHECK
1. SRS WARNING LIGHT CHECK
(a) Turn the ignition switch to the ON position and check that
the SRS warning light lights up.
(b) Check that the SRS warning light goes out after approx.
6 seconds.
HINT:

When the ignition switch is at ON and the SRS warning
light remains on or flashes, the airbag sensor assembly
has detected a malfunction code.

If, after approx. 6 seconds have elapsed, the SRS warn-
ing light sometimes lights up or the SRS warning light
lights up even when the ignition switch is OFF, a short in
the SRS warning light circuit can be considered likely.
Proceed to ºSRS warning light circuit malfunctionº on
page DI±632.
2. DTC CHECK (Using diagnosis check wire)
(a) Present troubles codes:
Output the DTC.
(1) Turn the ignition switch to the ON position and wait
for approx. 20 seconds.
(2) Using SST, connect terminals Tc and CG of the
DLC3.
SST 09843±18020
NOTICE:
Pay due attention to the terminal connecting position to
avoid a malfunction.
(b) Past troubles codes:
Output the DTC.
(1) Using service wire, connect terminals Tc and CG of
the DLC3.
SST 09843±18020
(2) Turn the ignition switch to the ON position and wait
for approx. 20 seconds.
NOTICE:
Pay due attention to the terminal connecting position to
avoid a malfunction.

AT0716AB0056H08231
Normal Code
ON
OFF0.25
0.25
Code 11 and 31
ON
OFF
0.5 2.54.0
1.5 0.5
DTC 11
DTC 31Repeat
F12396
TOYOTA Hand±held Tester
DLC3
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±503
2001 PRIUS (RM778U)
(c) Read the DTC.
Read the 2±digit DTC as indicated by the number of times
the SRS warning light blinks. As an example, the blinking
patterns, normal, 11 and 31 are shown in the illustration.

Normal code indication
The light will blink 2 times per second.

Malfunction code indication
The first blinking output indicates the first digit
of a 2±digit DTC. After a 1.5±second pause,
the second blinking output will indicate the
second digit.
If there are 2 or more codes, there will be a 2.5±second pause
between each code. After all the codes have been output, there
will be a 4.0±second pause and they will all be repeated.
HINT:

In the event of a number of trouble codes, indication will
start from the smallest numbered code.

If a DTC is not output or a DTC is output without terminal
connection, proceed to the Tc terminal circuit inspection
on page DI±636.
3. DTC CHECK (Using TOYOTA hand±held tester)
(a) Hook up the TOYOTA hand±held tester to the DLC3.
(b) Read the DTCs by following the prompts on the tester
screen.
HINT:
Please refer to the TOYOTA hand±held tester operator's manu-
al for further details.
4. DTC CLEARANCE (Not using service wire)
When the ignition switch is turned off, the diagnostic trouble
code is cleared.
HINT:
DTC might not be cleared by turning the ignition switch OFF.
In this case, proceed to the next step.
5. DTC CLEARANCE (Using service wire)
(a) Connect the 2 service wires to terminals Tc and A/B of
DLC3.
(b) Turn the ignition switch to ON and wait for approx. 6 se-
conds.

H10687
H15218
H15698
A/BTerminal
Tc
A/BOFF
Body
Ground
OFF
ON
OFF
Several
Seconds50 m sec.
50 m sec.
1 second
(±0.5 sec.)
Tc
Body
Ground
1 second
(±0.5 sec.)
1
23
45
F12396
TOYOTA Hand±held Tester
DLC3
DI±504
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
2001 PRIUS (RM778U)
(c) Starting with the Tc terminal, ground alternately terminal
Tc and terminal A/B twice each in cycles of 1.0 second.
Make sure that the terminals are grounded. Ensure the
terminal Tc remain grounded.
HINT:
When alternately grounding terminals Tc and A/B, release
ground from one terminal and immediately ground the other ter-
minal within an interval of 0.2 seconds.
If DTCs are not cleared, repeat the above procedure until the
codes are cleared.
(d) Several seconds after doing the clearing procedure, the
SRS warning light will blink in a 50 ± m sec. cycle to indi-
cate the codes which have been cleared.
6. DTC CLEARANCE (Using TOYOTA hand±held tester)
(a) Hook up the TOYOTA hand±held tester to the DLC3.
(b) Clear the DTCs by following the prompts on the tester
screen.
HINT:
Please refer to the TOYOTA hand±held tester operation's
manual for further details.

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±505
2001 PRIUS (RM778U)
7. RELEASE METHOD OF AIRBAG ACTIVATION PRE-
VENTION MECHANISM
An airbag activation prevention mechanism is built into the con-
nector for the squib circuit of the SRS.
When release of the airbag activation prevention mechanism is
directed in the troubleshooting procedure, as shown in the il-
lustration of the connectors on the next pages, insert paper
which has the same thickness as the male terminal between the
terminal and the short spring.
CAUTION:
Never release the airbag activation prevention mechanism
on the squib connector.
NOTICE:

Do not release the airbag activation prevention mech-
anism unless specifically directed by the trouble-
shooting procedure.

If the inserted paper is too thick the terminal and short
spring may be damaged, so always use paper with
the same thickness as the male terminal.

H15711
Airbag
Sensor
Assembly2
37
10
121
45
6
8
16
9
14
15
Side Airbag
Assembly (RH) (Squib)
Seat Belt
Pretensioner (RH) Side Airbag Sensor
Assembly (RH)
Front Airbag Sensor (RH)
Front Passenger Airbag
Assembly (Squib)
Spiral Cable
Steering Wheel
Pad (Squib)
Front Airbag Sensor (LH)
Side Airbag Sensor
Assembly (LH) Seat Belt
Pretensioner (LH)
Side Airbag
Assembly (LH) (Squib) 13
11
DI±506
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
2001 PRIUS (RM778U)