2001 TOYOTA PRIUS Service Repair Manual

DI±232
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Is DTC of battery ECU being output (See page DI±312)?
HINT:
In case of output of Information code 128, check whether V± wire harness of battery ECU DTC P3115 is open
or short at first. When there is no±abnormality, go to step 2.
Yes Check applicable DTC (See page DI±312).
NO
2 Check for open, short and +B short in wire harness between HV ECU IB and GB
terminals and battery ECU IB and GB terminals (See page IN±41).
HINT:
The HV ECU IB terminal has +B short if there is no open in wire harness and the voltage of the IB or GB
terminal is more than 5 V with the ignition ON.
NG Repair or replace wire harness.
OK
Replace HV ECU.

A14148
Hybrid Vehicle
Control ECU
Instrument Panel J/BI15
Ignition SW
Engine Room J/BFusible Link
Block No. 1ST2 R±W6
H13 2C2
W±R
2G2
W±R
1J9AM2
B
B±G
MAIN
Battery1B2
F121
F131
B±G
F181 Fusible Link
Block No. 2
ST2 AM27
8
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±233
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
The HV ECU checks the ST signal and detects malfunction. If the ST signal has +B short, the ST will always
be ON. Therefore, even with the IG ON when starting the THS, the system will start. To prevent this from
happening, the HV ECU detects the malfunction of the ST signal.
DTC P3100 ± Information code 142
INF. Code.Detecting ConditionTrouble Area
142When ST signal of HV ECU is ON, with ignition switch
turned OFF.
Wire harness

HV ECU

Ignition switch
WIRING DIAGRAM

DI±234
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check ignition switch (See page BE±17).
NG Replace ignition switch (See page SR±11).
NO
2 Check for +B short in wire harness between ignition switch ST2 terminal and HV
ECU ST2 terminal (See page IN±41).
HINT:
The HV ECU ST circuit has +B short if battery voltage is supplied to the ST2 terminal.
NG Repair or replace wire harness.
OK
Replace HV ECU.

± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±235
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
The HV ECU checks the internal operation of the ECU and detects malfunction.
DTC P3100 ± Information code 134, 135, 139, 140, 141, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152,
153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173,
174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194,
195, 196, 197, 198, 199, 200, 201, 202, 203, 271, 310, 390, 391, 392, 393
INF. Code.Detecting ConditionTrouble Area
134HV ECU internal error
HV ECU
135
139
140
141
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169

DI±236
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)INF. Code.
Detecting ConditionTrouble Area
170HV ECU internal error
HV ECU
171
HV ECU internal errorHV ECU
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
271
310
390
391
392
393
INSPECTION PROCEDURE
If any of the above information codes is output, replace the HV ECU.