2001 TOYOTA PRIUS check engine

A14013
START
ESTP
± DIAGNOSTICSENGINE
DI±149
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminal ESTP of ECM and body ground.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Start the engine.
CHECK:
Measure voltage between terminal ESTP of ECM and body
ground.
OK:
Voltage: 9 ± 14 V
OK Replace ECM.
NG
2 Check for open and short in harness and connector between ESTP of ECM and
HV ECU (See page IN±41).
OK Replace HV ECU.
NG
Repair or replace harness or connector.

DI±150
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
DTC P1656 OCV Circuit Malfunction
CIRCUIT DESCRIPTION
Refer to DTC P1349 on page DI±121.
DTC No.DTC Detecting ConditionTrouble Area
P1656
P1663Open or short in oil control valve circuit

Open or short in oil control valve circuit

Oil control valve

ECM
WIRING DIAGRAM
Refer to DTC P1349 on page DI±121.
INSPECTION PROCEDURE
HINT:
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.
TOYOTA hand±held tester
1 Check OCV circuit.
PREPARATION:
(a) Start the engine and warmed it up.
(b) Connect the TOYOTA hand±held tester and select VVT from ACTIVE TEST menu.
CHECK:
Check the engine speed when operate the OCV by the TOYOTA hand±held tester.
OK:
VVT system is OFF (OCV is OFF): Normal engine speed
VVT system is ON (OCV is ON): Rough idle or engine stalled
OK Check for intermittent problems
(See page DI±3).
NG
DI6VO±02

A14062
± DIAGNOSTICSENGINE
DI±151
2001 PRIUS (RM778U)
2 Check operation of OCV.
PREPARATION:
(a) Start the engine and warmed it up.
(b) Disconnect the OCV connector.
(c) Apply battery positive voltage between terminals of the
OCV.
CHECK:
Check the engine speed.
OK:
Rough idle or engine stalled.
NG Replace OCV.
OK
3 Check voltage between terminals OCV+ and OCV± of ECM connector
(See page DI±121).
NG Check and replace ECM (See page IN±41).
OK
4 Check for open and short in harness and connector between OCV and ECM
(See page IN±41).
NG Repair or replace.
OK
Check for intermitent problems
(See page DI±3).

A14062
DI±152
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
OBD II scan tool (excluding TOYOTA hand±held tester)
1 Check operation of OCV.
PREPARATION:
(a) Start the engine and warmed it up.
(b) Disconnect the OCV connector.
(c) Apply battery positive voltage between terminals of the
OCV.
CHECK:
Check the engine speed.
OK:
Rough idle or engine stalled
NG Replace OCV.
OK
2 Check voltage between terminals OCV+ and OCV± of ECM connector
(See page DI±121).
NG Check and replace ECM (See page IN±41).
OK
3 Check for open and short in harness and connector between OCV and ECM
(See page IN±41).
NG Repair or replace.
OK
Check for intermitent problems
(See page DI±3).

DI±154
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
2 Check remaining amount of fuel.
NG Supply fuel.
OK
3 Check air induction system (See page SF±1).
NG Repair or replace.
OK
4 Check for umusual noise or vibration when starting engine or racing.
NG Repair or replace.
OK
5 Check fuel pressure (See page SF±6).
NG Check and repair fuel pump and fuel pipe line
(See page SF±19).
OK
6 Check air flow meter (See page SF±22) and engine coolant temp. sensor
(See page SF±49).
NG Repair or replace.
OK

± DIAGNOSTICSENGINE
DI±155
2001 PRIUS (RM778U)
7 Check crankshaft position sensor and camshaft position sensor
(See page IG±1).
NG Repair or replace.
OK
8 Check throttle control motor and throttle position sensor (See page SF±24).
NG Repair or replace.
OK
Chack and replace ECM (See page IN±41).

A13635
ON
+B
E1
(±) (+)
A13636
IGSW
(+) (±)
± DIAGNOSTICSENGINE
DI±157
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminals +B and E1 or ECM connectors.
PREPARATION:
(a) Remove the ECM with connector still connected (See
page SF±62).
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals +B and E1 of the ECM
connectors.
OK:
Voltage: 9 ± 14 V
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI±22).
NG
2 Check for open in harness and connector between terminal E1 of ECM connector
and body ground (See page IN±41).
NG Repair or replace harness or connector.
OK
3 Check voltage between terminal IGSW 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 IGSW of the ECM con-
nector and body ground.
OK:
Voltage: 9 ± 14 V
OK Go to step 6.
NG

A13630
Engine Room J/B
AM2 Fuse
DI±158
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
4 Check AM2 fuse.
PREPARATION:
Remove the AM2 fuse from the engine room J/B.
CHECK:
Check the continuity of the AM2 fuse.
OK:
Continuity
NG Check for short in all harness and components
connected to AM2 fuse (See attached wiring dia-
gram).
OK
5 Check ignition switch (See page BE±16).
NG Replace ignition switch.
OK
Check and repair harness and connector be-
tween battery and ignition switch, and igni-
tion switch and ECM.