2001 TOYOTA PRIUS Service Repair Manual

B04757
DI820±01
A14089A14090
± DIAGNOSTICSHV BATTERY CONTROL SYSTEM
DI±315
2001 PRIUS (RM778U)
PRE±CHECK
1. PRECAUTION
(a) To distinguish a trouble and replace a defective part, take
necessary preventive measures against an electric shock
(See page IN±4).
(b) Some portions of the wiring harness in the THS vehicle
have the circuits, to which a high voltage is applied. To
prevent an electrical shock, be sure to observe the follow-
ing:
(1) Wear insulated gloves during inspection.
(2) Remove a service plug and do not start any repair
operation before 5 minutes have passed, then con-
firm that the voltage at the output terminals has
dropped down to 12 V or less.
(3) Use insulated tools during inspection.
(4) When disengaging wiring connectors, hold the con-
nector bodies to avoid pulling the wires. When en-
gaging wiring connectors, be sure to engage them
securely.
(c) Do not leave tools or parts (bolts, nuts, etc.) inside the
cabin.
(d) Do not carry metallic objects such as mechanical pencils
or scales.
2. DIAGNOSIS SYSTEM
(a) Description

The HV Battery ECU has a self±diagnosis system
by which malfunction in the computer itself or in Hy-
brid System is detected and the master warning
light in the combination meter and the Hybrid sys-
tem warning light in the multi±information display
lights up.

F12396
DLC3
TOYOTA hand±held tester
A04550
DLC3
912 3 4 56 78
16 15 14 13 12 11 10
DI±316
± DIAGNOSTICSHV BATTERY CONTROL SYSTEM
2001 PRIUS (RM778U)

To check the Diagnostic Trouble Codes (DTC), con-
nect the TOYOTA hand±held tester to the Data Link
Connector 3 (DLC3) on the vehicle. The TOYOTA
hand±held tester also enables you to erase the
DTC and check freeze frame data and various
forms of THS data.

Freeze frame data:
Freeze frame data records the battery condition
when a malfunction is detected.
When troubleshooting, this is useful for knowing the
battery condition.
(b) Check the DLC3.
The HV control ECU conforms to ISO 14230 for commu-
nication.
The terminal arrangement of the DLC3 complies with
SAEJ1962 and matches the ISO 14230 format.
Terminal No.Connection/Voltage or ResistanceCondition
7Bus
Line/Pulse generationDuring transmission
4Chassis Ground e Body Ground/1 W or lessAlways
5Signal Ground e Body Ground/1 W or lessAlways
16Battery Positive e Body Ground/10 ± 15 VAlways
HINT:
If your display shows UNABLE TO CONNECT TO VEHICLE
when you have connected the cable of the TOYOTA hand±held
tester to the DLC3, turned the motor switch ON and operated
the tester, there is a problem in the vehicle or tool.

If communication is normal when the tool is connected to
another vehicle, inspect the DLC3 on the original vehicle.

If communication is still not possible when the tool is con-
nected to another vehicle, the problem is probably in the
tool itself, so consult the Service Department.
3. INSPECT DIAGNOSIS
(a) Check the auxiliary battery.
(1) Measure the voltage of the auxiliary battery.
Voltage: 10 ± 15 V

A14089
B12009
F12396
DLC3
TOYOTA hand±held tester
± DIAGNOSTICSHV BATTERY CONTROL SYSTEM
DI±317
2001 PRIUS (RM778U)
(2) Inspect the auxiliary battery, fuses, fusible links, wir-
ing harness, connectors and ground.
(b) Check the master warning light.
(1) Turn the ignition switch ON and confirm that the
master warning light comes on.
HINT:
If the master warning light does not come on, suspect a burnt
fuse, burnt bulb, or open in wiring harness.
(2) When the ºREADYº light is ON, the master warning
light should go off.
If the lamp remains on, the diagnosis system has detected a
malfunction or abnormality in the system.
(c) Check the DTC.
(1) Prepare a TOYOTA hand±held tester.
(2) Connect the TOYOTA hand±held tester to the
DLC3.
(3) Turn the ignition switch ON and push the TOYOTA
hand±held tester main switch ON.
(4) Use the TOYOTA hand±held tester to check the
DTC and freeze frame data and note them down.
(For operating instructions, see the TOYOTA hand±
held tester operator's manual).
Since the HV battery ECU stores DTC and freeze
frame data, when troubleshooting, check all of the
DTC, write down the freeze fame data and perform
inspection according to the procedures of ºCircuit
Inspectionº.
Because the HV battery ECU is communicating with
the HV ECU, if any DTC is stored in the HV battery
ECU, check and record DTC stored in the HV ECU
(For tables for DTC, see page DI±177).
(5) See a related page to confirm details of the DTC.

F12396
DLC3
TOYOTA hand±held tester
DI±318
± DIAGNOSTICSHV BATTERY CONTROL SYSTEM
2001 PRIUS (RM778U)
(d) Clear DTC after completion of repair.
(1) Connect the TOYOTA hand±held tester to the
DLC3.
HINT:
Before clearing, check that DTC for the HV battery ECU, DTC
for the ECU which is related with freeze frame data and the
freeze frame data are recorded.
(2) Operate the TOYOTA hand±held tester to erase the
DTC (See the TOYOTA hand±held tester opera-
tor 's manual.).
4. CHECK FOR INTERMITTENT PROBLEMS
(a) Perform a simulation test (See page IN±30).
HINT:
In the simulation test, reproduce the condition at trouble occurrence based on the customer's comments and
the freeze frame data recorded with the DTC.
(b) Check the connector and terminal (See page IN±41).
(c) Handle the connector (See page IN±41).
5. TOYOTA HAND±HELD TESTER DISPLAY ITEMS
TOYOTA hand±held tester displayMeasurement Item
BATTERY SOCBattery State of charge
ONB CHARGE TIMECumulative number of times of on±board equalizing charging
BATTERY LO TIMECumulative number of times of battery dies
DC INHIBIT TIMECumulative number of times of discharge inhibition
IB MAIN BATTERYIB main battery current (with correction)
BATT BLOCK V#Battery block voltage
BAT BLOCK MIN VBattery block minimum voltage
MIN BAT BLOCK #Minimum voltage battery block
BAT BLOCK MAX VBattery block maximum voltage
MAX BAT BLOCK #Maximum voltage battery block
BATT INSIDE AIRAmbient temperature inside battery pack
BATTERY TOO HI #Cumulative number of times of too±high battery voltage
VMF FAN VOLTAGEBattery cooling fan voltage
AUX. BATT VAuxiliary battery voltage
WINCharge restriction value
WOUTDischarge restriction value
DELTA SOCDifference between MAX. and MIN. values of SOC at every battery block.
SBLW FAN ST RQSSBL cooling fan stop request signal
COOLING FAN HICooling fan operation in high speed
COOLING FAN MIDCooling fan operation in middle speed
COOLING FAN LOCooling fan operation in low
CCTLOff±board equalizing charge control signal
EQC0 DF RELAYEQC0 dead front relay
EQTR CHARGE STEQTR uniform charging start signal
ONBORD CHARGEOn±board equalizing charging status
PRE ONBORDE CHPre±On±board charging status
NORMAL STATUSNormal status
INSIDE RESIST #Inside resistance