2001 TOYOTA PRIUS relay

A14042A14043A14047
F
FON
Air
Air E EVSV is ON
VSV is OFF VSV is OFF
VSV is ON
CCV
DI±100
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
Check and replace ECM (See page IN±41).
14 Check VSV for CCV.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Turn the ignition switch ON.
CHECK:
Check the VSV function.
(1) Connect between terminal CCV of the ECM con-
nector and body ground (VSV ON).
(2) Disconnect between terminal CCV of the ECM con-
nector and body ground (VSV OFF).
OK:
VSV is ON:
Air does not flow from port E to port F.
VSV is OFF:
Air from port E flows out through port F.
OK Go to step 17.
NG
15 Check operation of VSV for CCV (See page SF±42).
OK Go to step 16.
NG
Replace VSV and charcoal canister, and then clean vacuum hoses between charcoal canister
and VSV for CCV.
16 Check for open and short in harness and connector between EFI main relay
(Marking: EFI) and VSV for CCV, and VSV for CCV and ECM (See page IN±41).
NG Repair or replace harness or connector.

DI±102
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
19 Check for open and short in harness and connector between EFI main relay
(Marking: EFI) and VSV for purge flow switching valve, and VSV for purge flow
switching valve and ECM (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN±41).

A14055
BatteryEAN1
Noise
Filter Engine Room J/B
Ignition SW Instrument
Panel J/B3
B±R I4 Ignition Coil
and Igniter No. 4
1ECM
14
Y
E7
E7
E7
E7 13
12
25IGT4
IGT3
IGT2
IGF
E711
IGT1 1
2
4
G
W
B±R
B±R
Y±G 3
4
2 1I3 Ignition Coil
and Igniter No. 3
3
4
2 1I2 Ignition Coil
and Igniter No. 2
2 I1 Ignition Coil
and Igniter No. 1
1
3
4
B±W
B±W
B±W
B±W
B±W
B±W
B±RB±RB±R
B±R
W±B W±B
W±B
W±B
W±B
W±B
B±W
W±B B±W
W±R
B±W IG2 Relay
5
1 3
29
1J
3
1J 2
1A
3
1K
AM2
2
1B
B
F12
12G 11
2B 5
2C 22G 1
B±W
W±R
67
IG2AM2
FL
Block
No. 1
F13
1
B±G
FL
Block
No. 2
MAIN
W±B
A
AJ7
J/C
W±B
A
J1
J/C
IE
B±W
DI±116
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:

If DTC P1300 is displayed, check No.1 ignition coil with igniter circuit.

If DTC P1305 is displayed, check No.2 ignition coil with igniter circuit.

If DTC P1310 is displayed, check No.3 ignition coil with igniter circuit.

If DTC P1315 is displayed, check No.4 ignition coil with igniter circuit.

Read freeze frame data using TOYOTA hand±held tester or OBD II scan tool. Because freeze frame
records the engine conditions when the malfunction is detected, when troubleshooting it is useful for
determining whether the vehicle was running or stopped, the engine warmed up or not, the air±fuel
ratio lean or rich, etc. at the time of the malfunction.

A09045
ON
START1
(+) (±)
± DIAGNOSTICSENGINE
DI±119
2001 PRIUS (RM778U)
NG Check and replace ECM (See page IN±41).
OK
7 Check ignition coil with igniter power source circuit.
PREPARATION:
Disconnect the ignition coil with igniter connector.
CHECK:
Measure voltage between terminal 1 of ignition coil with igniter
connector and body ground, when ignition switch is turned to
ºONº and ºSTARTº position.
OK:
Voltage: 9 ± 14 V
NG Repair ignition coil with igniter power source-
circuit.
OK
8 Check for open and short in harness and connector between ignition switch and
ignition coil with igniter (See page IN±41).
NG Repair or replace harness or connector.
OK
9 Check EFI main relay (Marking: EFI) (See page SF±37).
NG Replace EFI main relay (marking: EFI).
OK
Replace ignition coil with igniter.

A14058
ECM
+B 4
E8
BatteryW±RG±R
MREL 25 EFI Relay
I15 Ignition
SW EFI
IGSW 6
IE 1B35
AM2E9
J24 J25
J1
J/CE10 B
9 3
B
2C1 2
2G
24
A F121 3
1K 1F12 1A
1J 2
7 1
W±BW±R
B±W
B±G Engine Room J/B
F18
FL
Block
No. 2IA2
FL Block No. 19G±R
J7
J/C
B±W AM2 IG2
J/C Instrument
Panel J/B
F13 1
A
A W±BCB
MAIN
1 DI±156
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
ECM Power Source Circuit
CIRCUIT INSPECTION
When the ignition switch is turned on, battery positive voltage is applied to IG2 Relay, terminal IGSW of the
ECM and the EFI main relay (Marking: EFI MAIN) control circuit in the ECM sends a signal to terminal MREL
of the ECM switching on the EFI main relay.
This signal causes current to flow to the coil, closing the contacts of the EFI main relay and supplying power
to terminals +B of the ECM.
If the ignition switch is turned off, the ECM continues to switch on the EFI main relay for a maximum of 2
seconds for the initial setting of the IAC valve.
WIRING DIAGRAM
DI7DK±02

A14004
MREL
(+) (±)
A13630
Engine Room J/B
EFI Fuse
± DIAGNOSTICSENGINE
DI±159
2001 PRIUS (RM778U)
6 Check voltage between terminal MREL of ECM connector and body ground.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal MREL of the ECM con-
nector and body ground.
OK:
Voltage: 9 ± 14 V
NG Check and replace ECM (See page IN±41).
OK
7 Check EFI1 fuse.
PREPARATION:
Remove the EFI fuse from the engine room J/B.
CHECK:
Check continuity of EFI fuse.
OK:
Continuity
NG Check for short in all harness and components
connected to EFI1 fuse (See attached wiring
diagram).
OK
8 Check EFI main relay (Marking: EFI MAIN) (See page SF±37).
NG Replace EFI main relay.
OK

A14059
B±G
EFICIR OPN
Relay
MREL Engine Room J/B
1A
B
AECM
FC
F16
Fuel
Pump
IE 5
FL Block No. 1
MAIN
F12
BatteryE8
E9 259
W±B
J17
J/C J1
J/C
IG J7
J/C IA1
IA2
W±B
AA A W±B G±R B±R
F18
FL Block No. 2EFI
Relay
1K 1F
1B10
1F
2 121
3
2
1
3
3
1
11 52 1
3
F13G±R
B±R
7 14
4
G±R
± DIAGNOSTICSENGINE
DI±161
2001 PRIUS (RM778U)
Fuel Pump Control Circuit
CIRCUIT DESCRIPTION
When starting the engine with ignition switch:
HV ECU receives ST signal and decides to start the engine, and send the signal of the engine start prior
signal to the engine ECU by the communicatio between the engine ECU and HV ECU.
Engien ECU receives that signal and turns ON the circuit opening relay slightly earlier, then turns the fuel
pump.
When starting the engine in an intermittent operation:
With the cranking by MG1, NE signal comes in immediately, so the engine ECU receives the generation of
NE signal and turns the fuel pump. (At this time, no refernce of the communication from HV ECU)
When stopping the fuel pump:
When the signal to stop the engine comes in to the engine ECU from HV ECU from HV ECU side, the fuel
pump stops.
At the time of the fuel cut opetation such as deceleration by the engine brake, the fuel pump stops.
WIRING DIAGRAM
DI7T7±01

A14007
FC ON
(±) (+) DI±162
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
TOYOTA hand±held tester:
1 Connect TOYOTA hand±held tester and check operation of fuel pump (See page
DI±3).
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI±22).
NG
2 Check for ECM power source circuit (See page DI±156).
NG Repair or replace.
OK
3 Check circuit opening relay (Marking: C/OPN) (See page SF±38).
NG Replace circuit opening relay.
OK
4 Check voltage between terminal FC of ECM and body ground.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal FC of the ECM and body
ground.
OK:
Voltage: 9 ± 14 V