2001 TOYOTA PRIUS check engine

B04747
± INTRODUCTIONFOR ALL OF VEHICLES
IN±11
11 Author: Date:
2001 PRIUS (RM778U)
(h) After disconnecting or exposing a high±voltage connec-
tor or terminal, insulate it immediately using insulation
tape.
(i) The screw of a high±voltage terminal should be tightened
firmly to the specified torque. Both insufficient and exces-
sive tightening torque can cause failure.
(j) Call other engineers' attention to the vehicle which high±
voltage system is being inspected or repaired by hanging
a ºHigh Voltage Operation in Progress. Do Not Touchº
sign (See the next page).
(k) After servicing the high±voltage system and before rein-
stalling the service plug, check again that you have not
left a part or tool inside, that the high±voltage terminal
screws are firmly tightened, and that the connectors are
correctly engaged.

B04762
IN±14
± INTRODUCTIONFOR ALL OF VEHICLES
14 Author: Date:
2001 PRIUS (RM778U)
(b) Actions to be taken when HV battery is depleted
NOTICE:
Leaving a vehicle alone for 2 ± 3 months may cause electric
discharge from HV battery.
When this happens, replace the HV battery.
4. INSPECTION MODE
HINT:

The PRIUS automatically stops the engine while the ve-
hicle is stopped with the engine warmed up and battery
well charged if the A/C compressor operation is not re-
quired. Therefore, even if the vehicle stops for any reason
such as a check of ignition timing, the inspection mode
should be activated when continuous operation of the en-
gine is required.

The PRIUS has a skid control as traction control function.
When the wheel speed of the front wheels exceeds that
of the rear wheels, this function restrains the wheel speed
of the front wheels. It is necessary to activate the inspec-
tion mode and reset the skid control when turning only the
front wheels using a speedometer tester.
Activation inspection mode (Without using a hand±held tester)
(1) Perform the following (2) through (6) within 60 sec.
(2) Turn the ignition switch ON from OFF.
(3) With the shift lever in P position, fully depress the
accelerator pedal 2 times.
(4) With the shift lever in N position, fully depress the
accelerator pedal 2 times.
(5) With the shift lever in P position, fully depress the
accelerator pedal 2 times.
(6) Activate the inspecting mode and check that the hy-
brid system error warning light on the multi±center
display flashes.
(7) Turning the ignition switch to START starts the en-
gine's continuous operation.
NOTICE:

The idling speed in the inspection mode is approx.
1,000 rpm. The number of revolutions will increase up
to 1,500 rpm if the accelerator pedal is depressed to
a degree of less than 60%, and up to 2,250 rpm in a
case of 60% or more.

If a diagnosis code is recorded when entering the in-
spection mode, the master warning light and the error
warning light on the multi±center display is lit.

± INTRODUCTIONFOR ALL OF VEHICLES
IN±15
15 Author: Date:
2001 PRIUS (RM778U)

When the master warning light is lit during operation
in the inspection mode, deactivate the inspection
mode and inspect the diagnosed area.
HINT:
When continuous operation of the engine is required for such
as an exhaust leakage inspection, it is advisable as an easier
way to turn ON the FULL switch of the air conditioner.
5. SPECIAL NOTES FOR VEHICLE INSPECTION
(a) Vehicle conditions
(1) Before activating the service mode, turn the air con-
ditioner off, start the engine with the shift lever at P
position, and check that the engine stops within
several seconds after starting. (Engine warm up
check)
(2) Activate the service mode and inspect the vehicle.
The shift position for each test is as follows:
Test itemShift lever position
1. Vehicle straight traveling test (side
slip inspection)D
2. Braking force testN
3. Speedometer testD
4. Exhaust gas test (idling)P
5. Headlight testP
(3) Reset the service mode immediately after comple-
tion of inspection.
NOTICE:
Traveling on a road without resetting the service mode may
damage the transaxle.
(b) Special notes for speedometer test
NOTICE:
Rapid starting or quick acceleration/deceleration based on
the speedometer tester without load setting may damage
the transaxle.
(1) Depress the accelerator pedal slowly and gradually
accelerate at the time of measurement.
(2) After the measurement, use the brake to decelerate
gradually and stop.
(c) Special note for using the chassis dynamometer
Always set an appropriate load before starting the test.
NOTICE:
Rapid starting or quick acceleration/deceleration with in-
sufficient load may damage the transaxle.

IN±28
± INTRODUCTIONFOR ALL OF VEHICLES
28 Author: Date:
2001 PRIUS (RM778U)
8. FOR VEHICLES EQUIPPED WITH A CATALYTIC CONVERTER
CAUTION:
If large amount of unburned gasoline flows into the converter, it may overheat and create a fire haz-
ard. To prevent this, observe the following precautions and explain them to your customer.
(a) Use only unleaded gasoline.
(b) Avoid prolonged idling.
Avoid running the engine at idle speed for more than 20 minutes.
(c) Avoid spark jump test.
(1) Perform spark jump test only when absolutely necessary. Perform this test as rapidly as possible.
(2) While testing, never race the engine.
(d) Avoid prolonged engine compression measurement.
Engine compression tests must be done as rapidly as possible.
(e) Do not run engine when fuel tank is nearly empty.
This may cause the engine to misfire and create an extra load on the converter.
(f) Avoid coasting with ignition turned off.
(g) Do not dispose of used catalyst along with parts contaminated with gasoline or oil.
9. IF VEHICLE IS EQUIPPED WITH MOBILE COMMUNICATION SYSTEM
For vehicles with mobile communication systems such as two±way radios and cellular telephones, observe
the following precautions.
(1) Install the antenna as far as possible away from the ECU and sensors of the vehicle's electronic
system.
(2) Install the antenna feeder at least 20 cm (7.87 in.) away from the ECU and sensors of the ve-
hicle's electronic systems. For details about ECU and sensors locations, refer to the section on
the applicable component.
(3) Avoid winding the antenna feeder together with other wiring as much as possible, and also avoid
running the antenna feeder parallel with other wire harnesses.
(4) Check that the antenna and feeder are correctly adjusted.
(5) Do not install powerful mobile communications system.
10. FOR USING OBD II SCAN TOOL OR TOYOTA HAND±HELD TESTER
CAUTION:
Observe the following items for safety reasons:

Before using the OBD II scan tool or TOYOTA hand±held tester, the OBD II scan tool's instruc-
tion book or TOYOTA hand±held tester's operator manual should be read thoroughly.

Be sure to route all cables securely when driving with the OBD II scan tool or TOYOTA hand±
held tester connected to the vehicle. (i.e. Keep cables away from feet, pedals, steering wheel
and shift lever.)

Two persons are required when test driving with the OBD II scan tool or TOYOTA hand±held
tester, one person to drive the vehicle and the other person to operate the OBD II scan tool or
TOYOTA hand±held tester.

Important Points in the Customer Problem Analysis

What ±±±±± Vehicle model, system name

When ±±±±± Date, time, occurrence frequency

Where ±±±±± Road conditions

Under what conditions? ±±±±± Running conditions, driving conditions, weather conditions

How did it happen? ±±±±± Problem symptoms
(Sample) Engine control system check sheet.
ENGINE CONTROL SYSTEM Check Sheet
Customer's Name
Driver's Name
Data Vehicle
Brought in
License No.
Model and Model
Year
Frame No.
Engine Model
Odometer Reading
km
miles
Problem Symptoms
Engine does
not Start
Difficult to
Start
Poor Idling
Poor
Drive ability
Engine Stall
Others
Engine does not crankNo initial combustionNo complete combustion
Engine cranks slowly
Other
Incorrect first idleIdling rpm is abnormalHigh ( rpm)Low ( rpm)
Rough idling
Other
HesitationBack fireMuffler explosion (after±fire)Surging
Knocking
Other
Soon after startingAfter accelerator pedal depressed
After accelerator pedal released
During A/C operation
Shifting from N to D
Other
Data Problem
ConstantSometimes ( times per day/month)
Inspector's
Name
CUSTOMER PROBLEM ANALYSIS CHECK
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN±31
2001 PRIUS (RM778U)
1. CUSTOMER PROBLEM ANALYSIS
In troubleshooting, the problem symptoms must be confirmed accurately and all preconceptions must be
cleared away in order to give an accurate judgment. To ascertain just what the problem symptoms are, it is
extremely important to ask the customer about the problem and the conditions at the time it occurred.
Important Point in the Problem Analysis:
The following 5 items are important points in the problem analysis. Past problems which are thought to be
unrelated and the repair history, etc. may also help in some cases, so as much information as possible should
be gathered and its relationship with the problem symptoms should be correctly ascertained for reference
in troubleshooting. A customer problem analysis table is provided in Diagnostics section for each system
for your use.

IN±32± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
2001 PRIUS (RM778U)
2. SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK
The diagnostic system in the PRIUS fulfills various functions. The first function is the Diagnostic Trouble
Code Check in which a malfunction in the signal circuits to the ECU is stored in code in the ECU memory
at the time of occurrence, to be output by the technician during troubleshooting. Another function is the Input
Signal Check which checks if the signals from various switches are sent to the ECU correctly.
By using these check functions, the problem areas can be narrowed down quickly and troubleshooting can
be performed effectively. Diagnostic functions are incorporated in the following systems in the PRIUS.
SystemDiagnostic Trouble
Code CheckInput Signal Check
(Sensor Check)Diagnostic Test
Mode (Active Test)
Engine (with Check
Mode)
Hybrid Vehicle Control System
HV Battery Control System (with Check
Mode)
Anti±Lock Brake System With EBD & RBS
Electric Motor Power Steering
Supplemental Restraint System
Cruise Control System
Multiplex Communication System
Navigation System
Air Conditioning System

V07268
VIBRATION METHOD: When vibration seems to be the major cause.
CONNECTORS
WIRE HARNESS
PARTS AND SENSOR1
Slightly shake the connector vertically and horizontally.
Slightly shake the wire harness vertically and horizontally.
The connector joint, fulcrum of the vibration, and body
through portion are the major areas to be checked thorough-
ly.
Apply slight vibration with a finger to the part of the sensor
considered to be the problem cause and check that the mal-
function occurs.Shake Slightly
Swing Slightly
Vibrate Slightly
HINT:
Applying strong vibration to relays may result in open relays.
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN±35
2001 PRIUS (RM778U)
3. SYMPTOM SIMULATION
The most difficult case in troubleshooting is when there are no problem symptoms occurring. In such cases,
a thorough customer problem analysis must be carried out, then simulate the same or similar conditions and
environment in which the problem occurred in the customer's vehicle. No matter how much experience a
technician has, or how skilled he may be, if he proceeds to troubleshoot without confirming the problem
symptoms he will tend to overlook something important in the repair operation and make a wrong guess
somewhere, which will only lead to a standstill. For example, for a problem which only occurs when the en-
gine is cold, or for a problem which occurs due to vibration caused by the road during driving, etc., the prob-
lem can never be determined so long as the symptoms are confirmed with the engine hot condition or the
vehicle at a standstill. Since vibration, heat or water penetration (moisture) is likely cause for problem which
is difficult to reproduce, the symptom simulation tests introduced here are effective measures in that the ex-
ternal causes are applied to the vehicle in a stopped condition.
Important Points in the Symptom Simulation Test:
In the symptom simulation test, the problem symptoms should of course be confirmed, but the problem area
or parts must also be found out. To do this, narrow down the possible problem circuits according to the symp-
toms before starting this test and connect a tester beforehand. After that, carry out the symptom simulation
test, judging whether the circuit being tested is defective or normal and also confirming the problem symp-
toms at the same time. Refer to the problem symptoms table for each system to narrow down the possible
causes of the symptom.

B02389
B02390
HEAT METHOD: When the problem seems to occur when the suspect area is heated. 2
NOTICE:3 WATER SPRINKLING METHOD:
(1)
(2)
4 OTHER: When a malfunction seems to occur when electrical load is excessive.When the malfunction seems to occur on a rainy day or in a
high±humidity condition. Heat the component that is the likely cause of the malfunction
with a hair dryer or similar object. Check to see if the malfunction
occurs.
Sprinkle water onto the vehicle and check to see if the malfunc-
tion occurs.
Turn on all electrical loads including the heater blower, head
lights, rear window defogger, etc. and check to see if the mal-
function occurs.ON HINT:
If a vehicle is subject to water leakage, the leaked water may
contaminate the ECU. When testing a vehicle with a water leak-
age problem, special caution must be taken.
Malfunc-
tion
Do not heat to more than 60 °C (140 °F). (Temperature
is limited not to damage the components.)
Do not apply heat directly to parts in the ECU. (1)
(2)
Never sprinkle water directly into the engine compart-
ment, but indirectly change the temperature and hu-
midity by applying water spray onto the radiator front
surface.
Never apply water directly onto the electronic compo-
nents. NOTICE: IN±36
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
2001 PRIUS (RM778U)