2001 TOYOTA PRIUS diagnostic trouble code chart

DI±36
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
DTC P0116 Engine Coolant Temp. Circuit Range/
Performance Problem
CIRCUIT DESCRIPTION
Refer to DTC P0115 on page DI±32.
DTC No.DTC Detecting ConditionTrouble Area
When the engine starts, the water temp. is ±7°C (20°F) or
less. And, 20 min. or more after the engine starts, the engine
temp. sensor value is 5°C (41°F) or less (2 trip detection logic)
When the engine starts, the water temp. is between ±7°C
(20°F) and 10°C (50°F). And, 5 min. or more after the engine
starts, the engine coolant temp. sensor value is 5°C (41°F) or
less. (2 trip detection logic)
P0116When the fluctuations in the engine coolant tempeerature are
within 3 °C (37 °F)before and afrer the follwing conditions are
met:
1. IDL OFF time  250 sec.
2. Vehicle speed change of 30 km/h (19 mph) or more occurs
10 times or more.
3. 35 °C (95 °F)
Engine coolant temperature when the
ignition switch is turned ON < 60 °C (140 °F)
4. Intake air temperature after starting the engine  ±6.7 °C
(20 °F)
Engine coolant temp. sensor

Cooling system
INSPECTION PROCEDURE
HINT:

If DTC P0115 and P0116 are output simultaneously, engine coolant temp. sensor circuit may be open.
Perform troubleshooting of DTC P0115 first.

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.
1 Are there any other codes (besides DTC P0116) being output?
YES Go to relevant DTC chart.
NO
DI6UZ±03

DI±46
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
HINT:

If the vehicle run out of fuel, the air±fuel ratio is LEAN and DTC P0125 will be recorded .
The MIL then comes on.

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.

There is a possibility that P0125 is detected because of abnormal fuel system, so, when P0125 is mem-
orized, check P0171 and P0172 even if P0171 and P0172 are memorized.
1 Are there any other codes (besides DTC P0125) being output ?
YES Go to relevant DTC chart.
NO
2 Connect the OBD II scan tool or TOYOTA hand±held tester and read value for
voltage output of oxygen sensor (bank 1 sensor 1).
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand±held tester to the DLC3.
(b) Warm up engine to normal operating temp (above 75°C).
CHECK:
Read voltage output of the oxygen sensor (bank 1 sensor 1) when engine is suddenly raced.
HINT:
Perform quick racing to 4,000 rpm 3 times using accelerator pedal.
OK:
Both oxygen sensor (bank 1 sensor 1) output a RICH signal (0.45 V or more) at least once.
OK Go to step 9.
NG
3 Check for open and short in harness and connector between ECM and oxygen
sensor (bank 1 sensor 1) (See page IN±41).
NG Repair or replace harness or connector.
OK

P18349
0.48 V
0.42 V
± DIAGNOSTICSENGINE
DI±51
2001 PRIUS (RM778U)
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.
1 Are there any other codes (besides DTC P0130) being output?
YES Go to relevant DTC chart.
NO
2 Check the output voltage of oxygen sensor during idling.
PREPARATION:
Warm up the oxygen sensor the engine at 2,500 rpm for approx. 90 sec.
CHECK:
Use the OBD II scan tool or TOYOTA hand±held tester read the output voltage of the oxygen sensor during
idling.
OK:
Oxygen sensor output voltage:
Alternates repeatedly between less than 0.42 V and more than 0.48 V (See the Following table).
OK Go to step 7.
NG

DI±54
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
DTC P0133 Oxygen Sensor Circuit Slow
Responce (Bank 1 Sensor 1)
CIRCUIT DESCRIPTION
Refer to DTC P0125 on page DI±44.
DTC No.DTC Detecting ConditionTrouble Area
P0133
Response time for the oxygen sensor's voltage output to-
change from rich to lean, or from lean to rich, is 0.4 sec. or
more during constant vehicle speed after the engine is warmed
up
(2 trip detection logic)
Open or short in heated oxygen sensor circuit

Heated oxygen sensor

Air induction system

Fuel pressure

Injector

ECM
HINT:
Sensor 1 refers to the sensor closer to the engine body.
INSPECTION PROCEDURE
HINT:
Read freeze frame data using TOYOTA hand±held tester or OBD II scantool. 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.
1 Are there any other codes (besides DTC P0133) being output?
YES Go to relevant DTC chart.
NO
DI6V4±02

DI±60
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
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.
1 Are there any other codes (besides DTC P0136) being output?
YES Go to relevant DTC chart.
NO
2 Check for open and short in harness and connector between ECM and oxygen
sensor (See page IN±41).
NG Repair or replace harness or connector.
OK
3 Check output voltage of oxygen sensor.
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand±held tester to the DLC3.
(b) Warm up the engine to normal operating temp.
CHECK:
Read voltage output of oxygen sensor when engine suddenly raced.
HINT:
Perform a quick racing of 2,000 rpm or more 3 times by using the accelerator pedal.
OK:
Oxygen sensor output voltage: Alternates from 0.40 V or less to 0.50 V or more.
OK Check that each connector is properly con-
nected.
NG
Replace oxygen sensor.

A14462
OX Signal Waveform (Oscilloscope)
500 msec./DivisionOX1
OX2 1.0 V
0.5 V
0 V
1.0 V
0.5 V
0 V
± DIAGNOSTICSENGINE
DI±79
2001 PRIUS (RM778U)
(c) Drive the vehicle at 89 km/h (55 mph) or more for 5 min. or more.
(d) After confirming that the waveforms of the oxygen sensor, bank 1 sensor 1 (OX1), oscillate around 0.5
V during feedback to the ECM, check the waveform of the oxygen sensor, bank 1 sensor 2 (OX2).
HINT:

If there is a malfunction in the system, the waveform of the
oxygen sensor, bank 1 sensor 2 (OX2),is shown on the
left.

There are some cases where, even though a malfunction
exists, the MIL may either light up or not light up.

Normal waveform of OX2 is a smooth line of 0.6 to 0.7 V.
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.
1 Are there any other codes (besides DTC P0420) being output?
YES Go to relevant DTC chart.
NO
2 Check gas leakage on exhaust system.
NG Repair or replace.
OK
3 Check for open and short in harness and connector between heated oxygen
sensor (bank 1 sensor 1, 2) and ECM.
NG Repair or replace harness or connector.
OK

± DIAGNOSTICSENGINE
DI±131
2001 PRIUS (RM778U)
DTC P1431Vacuum Sensor for HC Adsorber and Catalyst Sys-
tem Circuit Range/Performance Problem
CIRCUIT DESCRIPTION
Refer to DTC P1430 on page DI±127.
DTC No.DTC Detecting ConditionTrouble Area
P1431
Conditions (a), (b), (c) and (d) continue with more than 10
seconds: (2 trip detection logic)
(b) PIM > 3.96 V
(c) VSV for HC Adsorber and Catalyst System is ON
(d) Engine speed is 1,000 rpm or more
(e) THW
0°C (32°F)

Vacuum sensor for HC adsorber and catalyst systemP1431Conditions (a), (b) and (c) continue with more than 10 se-
cond: (2 trip detection logic)
(a) PIM < 1.2 V
(b) Engine stopped
(c) VSV for HC Adsorber and Catalyst System is OFF
(d) THW
0°C (32°F)

Vacuum sensor for HC adsorber and catalyst system

Vacuum line
INSPECTION PROCEDURE
HINT:

If DTCs P1430, P1431, P0110, P0115, P0116, P0120, P0121 are output simultaneously, E2 (sensor
ground) may be open.

Read freeze frame data using hand±held tester. 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 was warmed up or not, the air±fuel ratio was lean or rich, etc. at
the time of the malfunction.

When a bypass valve has a trouble, it is possible that DTC P1341 will be detected ahead of DTC
P1436, and P1437, so in case that P1431 even if they are not memorized.
1 Are there any other codes (besides DTC P1431) being output?
YES Go to relevant DTC chart.
NO
DI7SZ±01

± DIAGNOSTICSENGINE
DI±153
2001 PRIUS (RM778U)
DTC P3190 Poor Engine Power
DTC P3191 Engine dose not Start
CIRCUIT DESCRIPTION
From the HV ECU, the ECM receives data such as power output required for the engine (required output),
estimated torque produced by the engine (estimated torque), engine RPM of control target (target RPM),
whether the engine is in start mode or not. Then, based on the required output and target RPM, the ECM
calculates a target torque that is to be produced by the engine and compares it with the estimated torque.
If the estimated torque is very low compared with the target torque, or the engine start mode continues at
the engine RPM or for the duration calculated by water temperature, an abnormal condition is detected.
DTC No.DTC Detecting ConditionTrouble Area
P3190
Following condition (a) to (e) continues at a fixed engine RPM
or a fixed length of time:
(a) Communication with HV ECU is normal.
(b) Engine RPM is a fixed value or more.
(c) Engine star mode is not active.
(d) Target torque is a fixed value or more.
(e) Ratio of estimated torque against target torque is less than
20 %.

Air induction system

Throttle body

Fuel pressure

Engine

Air flow meter

Out of fuel
Wt t
P3191
Following condition (a) to (c) continues at a fixed engine RPM
or for a fixed length of time:
(a) Vommunication with HV ECU is normal.
(b) Engine RPM is a fixed value or more.
(c) Engine start mode is active.
Water temp. sensor

Crankshaft position sensor

Camshaft position sensor

ECM
WIRING DIAGRAM
Refer to DTC P1636 on page DI±146.
INSPECTION PROCEDURE
1 Are there any other codes begin output?
YES Go to relevant DTC chart.
NO
DI7T6±01