
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

HV ECU±DTC & Information #
INFORMATION 1
INFORMATION 2
INFORMATION 3
INFORMATION 4
INFORMATION 5
INFORMATION 1
INFORMATION 2
INFORMATION 3
INFORMATION 4
INFORMATION 5
INFORMATION 1
INFORMATION 2
INFORMATION 3
INFORMATION 4
INFORMATION 5
INFORMATION 1
INFORMATION 2
INFORMATION 3
INFORMATION 4
INFORMATION 5
HV ECU±Information & Freezed frame data
MG1 REV
MG2 REV
MG1 TORQ
MG2 TORQ
POWER RQST
ENGINE SPD
MCYL CTRL POWER
SOC
WOUT CTRL POWER
WIN CTRL POWER
DRIVE CONDITION
INVERT TEMP ± MG1
INVERT TEMP ± MG2
MG1 TEMP
MG2 TEMP
PWR RESOURCE VM
PWR RESOURCE IB
SHIFT SENSOR 1
ACC SENSOR MAIN
ENG STOP RQST
IDLING REQUEST
ENGINE FUEL CUTrpm
rpm
rpm N´m
NmW
W
W%
( °C)
V
V A
Yes / No
Yes / No
Yes / NoHV BATT CH RQST
HCAC ABSRT RQST
ENG WARM UP RQT
STOP SW COND
CRUISE CONTROL
AUX. BATT V
EXCLUSIVE INFO1
EXCLUSIVE INFO2
EXCLUSIVE INFO3
EXCLUSIVE INFO4
EXCLUSIVE INFO5
EXCLUSIVE INFO6
LOAD CONDITION
DRIVING PATTEN1
DRIVING PATTEN2
DRIVING PATTEN3
IG OFF IN DRVIN
SG B IN REDUCIN
SG N IN REDUC/P
STEP ACC&BRAKE
IG OFF TIME
OCCURRENCE ORDERV Yes / No
Yes / No
Yes / No
Yes / No
Yes / No
Yes / No
Yes / No
Yes / No
Yes / No MG1 / MG2
min
± DTC
DTC
DTC
DTC
N´m
INFORMATION
°F
( °C) °F
( °C) °F
( °C) °F DI±180
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)

F12396
TOYOTA hand±held tester
DLC3
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±187
2001 PRIUS (RM778U)
(d) Clear the DTC after completion of repair.
(1) Connect the TOYOTA hand±held tester to the
DLC3.
Before clearing, check that DTCs and freeze frame
data of the HV ECU and the ECU related to the op-
eration history data are reccorded.
(2) Operate the TOYOTA hand±held tester to erase the
DTC (See the hand±held tester operator's manu-
al.).
4. FAIL±SAFE CHART
If any the following codes is recorded, the HV ECU enters the fail safe mode.
DTC codeINF. codeTrouble areaDriving condition
B2799101Immobilizeer MalfunctionImpossible to drive
C2692102Regenerative Brake Check±
C2693103Regenerative Brake Check±
104Limited driving
105Limited driving
106Limited driving
107Limited driving
108Limited driving
P1120109Accelerator Pedal Position
Sensor Circuit MalfunctionLimited drivingP1120
11 0Sensor Circuit MalfunctionLimited driving
111Limited driving
11 2Limited driving
11 3Limited driving (Creep vehicle speed)
11 4Limited driving (Creep vehicle speed)
P152011 5Stop Light Switch MalfunctionCruise control driving impossible
P156611 6Cruise Control System Mal-
functionCruise control driving impossible
P160011 7BATT MalfunctionNormal driving
11 8Impossible to drive/Normal driving when shift position is fixed
P178011 9Park/Neutral Positiont SwitchImpossible to drive/Normal driving when shift position is fixedP1780120
Park/Neutral Positiont Switch
System MalfunctionImpossible to drive
121
y
Impossible to drive/Normal driving when shift position is fixed
123Limited driving
P3000125HV B tt M lf tiLimited drivingP3000388HV Battery MalfunctionLimited driving
389Limited driving
P3001129HV Battery ECU MalfunctionLimited driving
130Limited driving
P3004131PCblMlftiImpossible to driveP3004132Power Cable MalfunctionNormal driving
133Limited driving

DI±192
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
309Limited driving
311Normal driving
312Normal driving
313Normal driving
314Normal driving
315Normal driving
316Limited driving
317Limited driving
318Limited driving
319Limited driving
320Limited driving
321Limited driving
322Limited driving
323Limited driving
324Limited driving
325Limited driving
326Limited driving
P3125327Converter & Inverter Assem-Limited drivingP3125328
Converter & Inverter Assem
bly MalfunctionLimited driving
329
y
Limited driving
330Limited driving
331Limited driving
332Limited driving
333Limited driving
334Limited driving
335Limited driving
336Limited driving
337Limited driving
338Limited driving
339Limited driving
340Limited driving
341Limited driving
342Limited driving
343Limited driving
344Limited driving
345Limited driving
P3130346Inverter Cooling System Mal-Normal drivingP3130347
Inverter Cooling System Mal
functionNormal driving
P3135348Circuit Breaker Sensor Mal-Normal drivingP3135349
Circuit Breaker Sensor Mal
functionNormal driving
P3140350It l kMlf tiNormal drivingP3140351Interlock MalfunctionNormal driving
P3145352Vehicle Speed Sensor Circuit
MalfunctionCruise control driving impossible

± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±193
2001 PRIUS (RM778U)
5. CHECK FOR INTERMITTENT PROBLEMS
(a) Perform a simulation test (See page IN±41).
In the simulation test, reproduce the driving condition at the trouble occurrence according to the cus-
tomer 's comments and freeze frame data recorded with DTC, such as an opening angle of the acceler-
ator pedal, SOC, engine coolant temperature, engine rpm, and MG/1MG2 rpm and torque.
(b) Check the connector and terminal (See page IN±41).
(c) Handle the connector (See page IN±41).
6. TOYOTA HAND±HELD TESTER DISPLAY ITEMS
TOYOTA Hand±held tester displayMeasurement Item
1 BEF LATST ORNumber of operation of 1 trip before last
1 BEF LATST TRPNumber of trips before last
2 BEF LATST ORNumber of operation 2 trips before last
2 BEF LATST TRPNumber of trips 2 before last
ABNML CON BR±HVCommunication malfunction between HV ECU and brake
ACC SENSOR MAINMain accelerator sensor
ACC SENSOR SUBSub accelerator sensor
ACC TENT TRBLETentative trouble of accelerator
ACC THROTTLEAccelerator throttle
ACCEL MODEHistory of acceleration and reduction
AIR CON REQUESTAir conditioner request
AUX. BATT LOWAuxiliary battery becomes week
AUX. BATT VVoltage of auxiliary battery
BATT HIGH TEMPTemperature of the battery is too high
BATT HIGH VOLTVoltage of the battery is too high
BATT LOW BOLTVoltage of the battery is low
BATT OVER LOADBattery is overloaded
BATT SAVE RQSTRequest to save the main battery
BATTERY FULLBattery full
BRAKE TORQBrake torque
CELL TEMP±MAXHighest temperature of all battery cells
CELL TEMP±MINLowest temperature of all battery cells
CHG RESTRICTIONCharge restriction
COOLANT TEMPWater temperature
CRUISE CONTROLCondition of the cruise control
DC/DC CONV STOPDC/DC converter stop signal
DC/DC CONV STOPFactors causing DC/DC converter to stop
DC/DC STOP FACTDC/DC converter has stopped at least once
DC/DC V UNSETDC/DC voltage is unsettled
DCHG RQST SOCDischarge request to adjust SOC
DISCHAG INHIBITBattery is inhibited to discharge

DI82L±02
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±197
2001 PRIUS (RM778U)
DIAGNOSTIC TROUBLE CODE CHART
HINT:
Parameters listed in the chart may not be exactly the same as your reading due to the type of instrument
or other factors.
If a malfunction code is displayed during the DTC check in the check mode, check the circuit for that code
listed in the table below. For the details of each code, turn to the page referred to under the ''See page'' for
the respective ''DTC No.'' in the DTC chart.
DTC No.
(See page)Detection ItemTrouble Area
Hybrid
System
Warning
Light*
Memory
B2799
(DI±210)Immobilizer MalfunctionWire Harness
Immobilizer System
C2692
(DI±212)Regenerative Brake Check±
C2693
(DI±212)Regenerative Brake Check±X
P1120
(DI±213)Accelerator Pedal Position
Sensor Circuit MalfunctionAccelerator Pedal Position Sensor
Wire Harness
P1520
(DI±215)Stop Light Switch (Cruise Con-
trol System) MalfunctionStop Light Switch
Wire Harness
Brake ECU
X
P1566
(DI±217)Cruise Control System Malfunc-
tionStop Light Switch
Brake ECU
Wire Harness
X
P1600
(DI±219)BATT MalfunctionHV Fuse
Wire Harness
P1780
(DI±221)Park/Neutral Position Switch
System MalfunctionPark/Neutral Position Switch
Wire Harness
P3000
(DI±223)HV Battery Malfunction
HV Battery System
High Voltage Fuse
Power Cable
HV Battery Cooling System
/X
P3001
(DI±224)HV Battery ECU MalfunctionBattery ECU
P3004
(DI±225)Power Cable Malfunction
Power Cable
HV Battery System
Service Plug
System Main Relay
Converter & Inverter Assembly
/X
P3100
(DI±229)HV ECU Malfunction
Wire Harness
HV ECU
ECM
Crankshaft Position Sensor
Camshaft Position Sensor
Ignition Switch
P3101
(DI±237)Engine System MalfunctionEngine
HV Transaxle
P3105
(DI±238)Battery ECU Communication Cir-
cuit MalfunctionWire Harness
Battery ECU
P3106
(DI±240)ECM Communication Circuit
MalfunctionWire Harness
ECM/X

± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±199
2001 PRIUS (RM778U)
INFORMATION CODE (TOYOTA Hand±held tester only)
DTC NO.INF. CodeDetection ItemDetecting Condition
B2799101Immobilizer MalfunctionNo input of signal from transponder key ECU
C2692102Regenerative Brake CheckRegenerative brake check
C2693103Regenerative Brake CheckRegenerative brake check
104Open or short in main accelerator sensor circuit
105+B short in main accelerator sensor circuit
106Main sensor internal error
107Open or short in sub accelerator sensor circuit
108+B short in sub accelerator sensor circuit
P1120109Accelerator Pedal Position
Sensor Circuit MalfunctionSub sensor internal errorP1120
11 0Sensor Circuit MalfunctionWhen difference between main sensor value and sub sensor value is large
111When sub sensor value changes while main sensor value does not
11 2When main sensor value changes while sub sensor value does not
11 3When any of the information code 104 ± 112 continues to appear
11 4Accelerator pedal not smoothly returning to original position
P152011 5
Stop Light Switch
(Cruise Control System)
Malfunction
Open or short in stop light switch circuit
P156611 6Cruise Control System
MalfunctionWhen STP signal of HV ECU is inconsistent with that of brake ECU, with
cruise control indicator ON
P160011 7BATT MalfunctionHV ECU back±up power source circuit malfunction
11 8When more than 2 main signals are ON
11 9P k/N t l P iti S it hWhen main signal is not turned ON even though sub signal has been input
P1780120Park/Neutral Position Switch
System MalfunctionOpen or short in sub sensor circuit
121
System Malfunction
When shift position detected by main signal is different from that detected
by sub signal
123HV B tt M lf tiInput of abnormal signal from battery ECU (HV battery system malfunction)
125HV Battery MalfunctionInput of abnormal signal from battery ECU (high voltage fuse blown out)
P3000388Discharge Inhibition Control
MalfunctionWhen charged battery is low due to leaving the vehicle in N position, gas
shortage or HV system malfunction
389Drop of High VoltageWhen main battery is dead or main battery is dead due to HV system mal-
function
P3001129HV Battery ECU MalfunctionBattery ECU malfunction
130HV Battery MalfunctionWhen HV battery voltage becomes lower than inverter voltage
P3004
131
PCblMlfti
When main fuse is blown out, service plug is disconnected or limiter resis-
tance is cut off
P3004
132
Power Cable MalfunctionWhen inverter voltage sensor is malfunctioning or limiter resistance value
increases
133HV Battery MalfunctionInput of abnormal signal from battery ECU
134HV ECU I t l EHV ECU Internal Error
135HV ECU Internal ErrorHV ECU Internal Error
P3100136GO Signal ErrorOpen or short in GO signal circuit
137Engine Speed Sensor
MalfunctionEngine speed sensor malfunction

± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±205
2001 PRIUS (RM778U)DTC NO.
INF. CodeDetection ItemDetecting Condition
326Generator inverter current sensor malfunction (V phase sub sensor)
327Open in generator inverter current sensor (V phase sub sensor)
328Generator inverter current sensor malfunction (V phase main sensor)
329(when there is a history that the state of malfunction continued during in-
verter fail safe mode)
330Open in generator inverter current sensor (V phase main sensor)
331(when there is a history that the state of malfunction continued during in-
verter fail safe mode)
332Generator inverter current sensor V phase performance problem
333Generator Inverter Current
(when there is a history that the state of malfunction continued during in-
verter fail safe mode)
334
Generator Inverter Current
Sensor MalfunctionGenerator inverter current sensor malfunction (W phase sub sensor)
335Open in generator inverter current sensor (W phase sub sensor)
P3125336Generator inverter current sensor malfunction (W phase main sensor)P3125
337(when there is a history that the state of malfunction continued during in-
verter fail safe mode)
338Open in generator inverter current sensor (W phase main sensor)
339(when there is a history that the state of malfunction continued during in-
verter fail safe mode)
340Generator inverter current sensor W phase performance problem
341(when there is a history that the state of malfunction continued during in-
verter fail safe mode)
342Motor Gate Shutdown Signal+B short in generator gate shutdown signal circuit
343
Motor Gate Shutdown Signal
Line ConnectionOpen or GND short in generator gate shutdown signal circuit
344Failure in Monitoring Genera-
tor Torque PerformanceFailure in monitoring generator torque performance
345Abnormal Current Value of
GeneratorAbnormal current value of generator
P3130346Inverter Cooling System Mal-Water pump system malfunctionP3130347
Inverter Cooling System Mal
functionElectric cooling fan system malfunction
P3135348Circuit Breaker Sensor Mal-GND short in circuit breaker sensorP3135349
Circuit Breaker Sensor Mal
functionOpen or +B short in circuit breaker sensor
P3140350It l kMlf tiSafety devices operating with vehicle is stopped (ILK signal ON)P3140351Interlock MalfunctionOpen circuit in interlock signal circuit while vehicle is running
P3145352Vehicle Speed Sensor Circuit
MalfunctionNo input of vehicle speed signal during cruise control driving