05–760
DIAGNOSTICS – HYBRID CONTROL SYSTEM 05JBO–01
DTC P0AA1/224 HYBRID BATTERY POSITIVE CONTACTOR
CIRCUIT STUCK CLOSED
DTC P0AA2/225 HYBRID BATTERY POSITIVE CONTACTOR
CIRCUIT STUCK OPEN
CIRCUIT DESCRIPTION
The SMRs (System Main Relays) connect and disconnect the
high–voltage power supply circuit in accordance with requests
from the HV control ECU. To ensure a reliable operation, they
consists of a total of three relays (one for the negative side and
SMR2 two for the positive side).
To connect, SMR1 and SMR3 turn ON initially. Then, SMR2
SMR1 Resistor turns ON and SMR1 turns OFF. This process protects the circuit
from the high–voltage surge current by allowing the limit current
to flow via the resistor. To disconnect, SMR2 and SMR3 turn
Service Plug Grip OFF in that order. The HV control ECU checks that the relays
have turned OFF properly.
The HV control ECU monitors the proper operation of the SMRs
(CON1, CON2 and CON3) to check for malfunction.
SMR3
A93714
DTC No. INF Code DTC Detection Condition Trouble Area
Wire harness or connector
P0AA1 224 Open or +B short in system main relay No. 1 circuit System main relay No. 1
HV control ECU
Wire harness or connector
P0AA2 225 GND short in system main relay No. 1 circuit System main relay No. 1
HV control ECU
2004 Prius – Preliminary Release (RM1075U)
Author: Date: 924
05–761
DIAGNOSTICS – HYBRID CONTROL SYSTEM
WIRING DIAGRAM
HV Battery Assembly HV Control ECU
(+)
2 1 2
G G
S22 IC1 H16 CON2
System Main
Relay No. 2
System Main
Service Resistor
Plug 1 2 1
Grip R R
S22 IC1 H16 CON1
System Main
Relay No. 1 (–)
3 22 3
Y Y
S22 IC1 H16 CON3
System Main
Relay No. 3
A92107
INSPECTION PROCEDURE
CAUTION:
Before inspecting the high–voltage system, take safety precautions to prevent electrical
shocks, such as wearing insulated gloves and removing the service plug grip. After removing
the service plug grip, put it in your pocket to prevent other technicians from reconnecting it
while you are servicing the high–voltage system.
After disconnecting the service plug grip, wait at least for 5 minutes before touching any of the
high–voltage connectors or terminals.
HINT:
At least 5 minutes is required to discharge the high–voltage condenser inside the inverter.
1 INSPECT SYSTEM MAIN RELAY NO.1 (See page 21–40)
NG REPLACE SYSTEM MAIN RELAY NO.1
(See page 21–83)
OK
2004 Prius – Preliminary Release (RM1075U)
Author: Date: 925
05–762
DIAGNOSTICS – HYBRID CONTROL SYSTEM
2 CHECK HARNESS AND CONNECTOR(HYBRID VEHICLE CONTROL ECU –
SYSTEM MAIN RELAY NO.1)
CAUTION:
Wear insulated gloves before performing the following op-
eration.
(a) Turn the power switch OFF.
(b) Remove the service plug grip (see page 21–116).
NOTICE:
Turning the power switch ON (READY) with the service
plug grip removed could cause malfunction. Therefore,
never turn the power switch ON (READY) in this state.
(c) Disconnect the H16 HV control ECU connector.
(d) Disconnect the S22 system main relay No. 1 connector.
H16 (e) Turn the power switch ON (IG).
HINT:
DTCs for the interlock switch system are output when turning
the power switch ON (IG) with the service plug grip removed.
CON1
(f) Measure the voltage between the terminal of the HV con-
trol ECU connector and body ground.
HV Control ECU Connector A65745 Standard:
Tester Connection Specified Condition
Wire Harness Side: CON1 (H16–1) – Body ground Below 1 V
System Main Relay No. 1 Connector (g) Turn the power switch OFF.
S22 (h) Check the resistance between the wire harness side con-
nectors.
CON1 Standard (Check for open):
Tester Connection Specified Condition
CON1 (H16–1) – CON1 (S22–1) Below 1 Ω
Front View Standard (Check for short):
A93715
Tester Connection Specified Condition
CON1 (H16–1) or CON1 (S22–1) – Body ground 10 kΩ or higher
(i) Reconnect the system main relay No. 1 connector.
(j) Reconnect the HV control ECU connector.
(k) Reinstall the service plug grip (see page 21–116).
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
REPLACE HYBRID VEHICLE CONTROL ECU (See page 21–124)
2004 Prius – Preliminary Release (RM1075U)
Author: Date: 926
