Page 1817 of 2572
A67446
BATT (+)E1 (-)
E5
ECM
E9
ECM
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
05-231
421 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
2 INSPECT ECM (BATT VOLTAGE)
(a) Measure the voltage of the ECM connectors.
Standard:
Tester ConnectionSpecified Condition
E5-3 (BATT) - E9-1 (E1)9 to 14 V
OK REPLACE ECM (See page 10-9)
NG
Page 1818 of 2572

Y
A80025
A67445A92625
EFI NO. 1 Fuse
BATTE5
ECM
Engine Room J/B Wire Harness Side
A80025A92626
EFI NO. 1 FuseEngine Room J/B Wire Harness Side
05-232
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
422 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
3 CHECK WIRE HARNESS (ECM - EFI NO. 1 FUSE, EFI NO. 1 FUSE - BATTERY)
(a) Check the wire harness between the EFI NO. 1 fuse and
ECM.
(1) Remove the EFI NO. 1 fuse from the engine room
J/B.
(2) Disconnect the E5 ECM connector.
(3) Measure the resistance of the wire harness side
connectors.
Standard:
Tester ConnectionSpecified Condition
J/B EFI NO. 1 fuse terminal 2 - E5-3 (BATT)Below 1 W
J/B EFI NO. 1 fuse terminal 2 or E5-3 (BATT) - Body ground10 kW or higher
(b) Check the wire harness between the EFI NO. 1 fuse and
battery.
(1) Remove the EFI NO. 1 fuse from the engine room
J/B.
(2) Disconnect the battery positive cable.
(3) Measure the resistance of the wire harness side
connectors.
Standard:
Tester ConnectionSpecified Condition
Battery positive cable - J/B EFI NO. 1 fuse terminal 1Below 1 W
Battery positive cable or J/B EFI NO. 1 fuse terminal 1
- Body ground10 kW or higher
NG REPAIR OR REPLACE HARNESS AND
CONNECTOR
OK
CHECK AND REPLACE ENGINE ROOM J/B
Page 1819 of 2572

- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
05-233
423 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DTC P0604 INTERNAL CONTROL MODULE RANDOM
ACCESS MEMORY (RAM) ERROR
DTC P0606 ECM/PCM PROCESSOR
DTC P0607 CONTROL MODULE PERFORMANCE
DTC P0657 ACTUATOR SUPPLY VOLTAGE
CIRCUIT/OPEN
MONITOR DESCRIPTION
The ECM continuously monitors its internal memory status, internal circuits, and output signals to the throttle
actuator. This self-check ensures that the ECM is functioning properly. If any malfunction is detected, the
ECM will set the appropriate DTC and illuminate the MIL.
The ECM memory status is diagnosed by internal ºmirroringº of the main CPU and the sub CPU to detect
random access memory (RAM) errors. The two CPUs also perform continuous mutual monitoring. The ECM
sets a DTC if: 1) outputs from the 2 CPUs are different and deviate from the standards, 2) the signals to the
throttle actuator deviate from the standards, 3) a malfunction is found in the throttle actuator supply voltage,
and 4) any other ECM malfunction is found.
DTC No.DTC Detection ConditionTrouble Area
P0604
P0606
P0607
P0657
ECM internal error
(1trip detection logic)ECM
MONITOR STRATEGY
Related DTCs
P0604: RAM errors
P0606: CPU malfunction
P0607: ECM range check
P0657: ETCS (Electrical throttle control) power supply circuit in ECM
Required sensors / components (Main)ECM
Required sensors / components (Related)-
Frequency of operationContinuous
DurationWithin 1 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
The monitor will run whenever these DTCs are not presentSee page 05-16
TYPICAL MALFUNCTION THRESHOLDS
RAM Error P0604:
RAMRAM check failure
CPU malfunction P0606:
Either of the following conditions is met:Condition 1 or 2
1. Difference between TP of main CPU and TP of sub CPU0.3 V or more
2. Difference between APP of main CPU and APP of sub
CPU0.3 V or more
05EVN-05
Page 1820 of 2572
05-234
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
424 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
ECM range check P0607:
Either of the following conditions is met:Condition 1 or 2
1. All of the following conditions are met:Conditions (a), (b) and (c)
(a) CPU reset1 time or more
(b) Difference between TP and APP learned0.4 V or more
(c) Electronic throttle actuatorOFF
2. CPU reset2 times or more
ETCS power supply circuit in ECM P0657:
ETCS power supply when ignition switch turns from OFF to
ON7 V or more
INSPECTION PROCEDURE
HINT:
Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the
engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help deter-
mine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean
or rich, and other data from the time the malfunction occurred.
REPLACE ECM (See page 10-9)
Page 1821 of 2572

- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
05-235
425 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DTC P0617 STARTER RELAY CIRCUIT HIGH
MONITOR DESCRIPTION
While the engine is being cranked, the battery positive voltage is applied to terminal STA of the ECM.
If the vehicle is being driven and the ECM detects the starter control signal (STA), the ECM concludes that
the starter control circuit is malfunctioning. The ECM will turn on the MIL and will set a DTC.
DTC No.DTC Detecting ConditionTrouble Area
P0617
When conditions (a), (b) and (c) are met and the battery (+B)
voltage 10.5 V or more is applied for 20 seconds:
(1 trip detection logic)
(a) Vehicle speed greater than 12 mph (20 km/h)
(b) Engine revolution greater than 1,000 rpm
(c) STA signal ON
Short in PNP switch assy circuit
PNP switch assy
Ignition switch
ECM
MONITOR STRATEGY
Related DTCsP0617: Starter signal
Required sensors / components (Main)Starter relay and PNP switch
Required sensors / components (Related)CKP sensor and vehicle speed sensor
Frequency of operationContinuous
Duration20 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
The monitor will run whenever this DTC is not presentSee page 05-16
Battery voltage10.5 V or more
Vehicle speed20 km/h (12.4 mph) or more
Engine RPM1,000 rpm or more
TYPICAL MALFUNCTION THRESHOLDS
Starter signalON
05EVO-05
Page 1822 of 2572
A90303
2ECM
Starter
Battery4
B-WEB1
1 1
BS1
S2W-B
A
J2
J/CJ7
J/C A
AE91
BR
BR
EHE1
EE FL
Main WAM2 1C
2
1 1
L-Y
10 1
ALTInstrument
Panel J/B
Assy
1A 16
BAM1
F7
FL Block AssyIC1Y WI15
Ignition Switch
B-Y
2
7813
B-W
STARTER
L B
1 5Engine
Room R/B
No. 2
4 1
2
B-W
2IC1
P1
PNP
Switch
STA 5
W-R2
3
B17
E7 AM1
AM2ST1
ST2
2
2
3
EB2 2 IC1
STARTER
Relay2
2 24 EB2
B B L-W
B-R Engine
Room R/B
No. 2 05-236
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
426 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
WIRING DIAGRAM
Page 1823 of 2572

- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
INSPECTION PROCEDURE
HINT:
Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the
engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help deter-
mine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean
or rich, and other data from the time the malfunction occurred.
Hand-held tester:
1 READ VALUE OF HAND-HELD TESTER (STA SIGNAL)
(a) Connect the hand-held tester to the DLC3.
(b) Turn ON the ignition switch. Push the hand-held tester main switch.
(c) On the hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST
/ ALL / STARTER SIG. Read the values.
Result:
Ignition Switch ConditionONSTART
STA signalOFFON
OK REPLACE ECM (See page 10-9)
NG
2 INSPECT PARK/NEUTRAL POSITION SWITCH ASSY (See page 05-922)
OK:
When shift lever is in the N position, the PNP switch is ON.
When shift lever is in the P position, the PNP switch is OFF.
NG REPLACE PARK/NEUTRAL POSITION SWITCH
ASSY (See page 40-3) (Go to step 3 AFTER RE-
PLACEMENT)
OK
3 READ VALUE OF HAND-HELD TESTER (STA SIGNAL)
(a) Connect the hand-held tester to the DLC3.
(b) Turn ON the ignition switch. Push the hand-held tester main switch.
(c) On the hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST
/ ALL / STARTER SIG. Read the values.
Result:
Ignition Switch ConditionONSTART
STA signalOFFON
OK SYSTEM OK
NG
Page 1824 of 2572
1
5 6 2 3
7 8 4
A56879
I15
Ignition
SwitchAM1
AM2 ST2
ST1
05-238
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
428 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
4 INSPECT IGNITION OR STARTER SWITCH ASSY
(a) Measure the resistance of the ignition switch terminals.
Standard:
Switch ConditionTester ConnectionSpecified Condition
LOCK1 - 2
7 - 810 kW or higher
START1 - 2
7 - 8Below 1 W
NG REPLACE IGNITION OR STARTER SWITCH
ASSY (Go to next step 5 AFTER REPLACE-
MENT)
OK
5 READ VALUE OF HAND-HELD TESTER (STA SIGNAL)
(a) Connect the hand-held tester to the DLC3.
(b) Turn ON the ignition switch. Push the hand-held tester main switch.
(c) On the hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST
/ ALL / STARTER SIG. Read the values.
Result:
Ignition Switch ConditionONSTART
STA SignalOFFON
OK SYSTEM OK
NG
REPAIR OR REPLACE HARNESS AND CONNECTOR