Page 1809 of 2572

A82389
Idle Engine
RPM
Small Target RPM
Actual Idle RPMLarge
Learning Value
of the Idle Speed
ControlMaximum
Minimum
Time 0
Time
- DIAGNOSTICSSFI SYSTEM (3MZ-FE)
05-587
777 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DTC P0505 IDLE AIR CONTROL SYSTEM
MONITOR DESCRIPTION
The idle speed is controlled by the Electronic Throttle Control System (ETCS).
The ETCS is composed of the throttle motor, which operates the throttle valve, and the throttle position sen-
sor, which detects the opening angle of the throttle valve.
The ECM controls the throttle motor to provide the proper throttle valve opening angle to obtain the target
idle speed.
The ECM regulates the idle speed by opening and closing the throttle valve using the ETCS. The ECM con-
cludes that the idle speed control ECM function is malfunctioning if: 1) the actual idle RPM varies more than
the specified amount five times or more during a drive cycle, or 2) a learning value of the idle speed control
remains at the maximum or minimum five times or more during a drive cycle. The ECM will turn on the MIL
and set a DTC.
Example:
If the actual idle RPM varies from the target idle RPM by more than 200* rpm five times during a drive cycle,
the ECM will turn on the MIL and will set a DTC.
HINT:
*: RPM threshold varies with engine load.
DTC No.DTC Detection ConditionTrouble Area
P0505Idle speed continues to vary greatly from target speed
(1 trip detection logic)ETCS
Air induction system
PCV hose connection
05C1S-13
Page 1810 of 2572

05-588
- DIAGNOSTICSSFI SYSTEM (3MZ-FE)
778 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
MONITOR STRATEGY
Related DTCsP0505: IAC Functional Check
P0505: IAC Range Check
Required sensors / components (Main)ETCS (Electrical throttle control system)
Required sensors / components (Related)CKP sensor, ECT sensor and VSS
Frequency of operationContinuous
Duration10 minutes
MIL Operation2 driving cycles
Sequence operationNone
TYPICAL ENABLING CONDITIONS
The monitor will run whenever this DTC is not presentSee page 05-377
EngineRunning
TYPICAL MALFUNCTION THRESHOLDS
Either of the following conditions is met:Condition 1 or 2
1. Frequency that both of the following conditions (a) and (b)
are met:5 times or more
(a) Engine RPM - target engine RPMLess than -100 rpm, or more than 150 rpm
(b) Vehicle conditionStop after vehicle was driven at 10 km/h (6.25 mph) or more
2. Frequency that both of the following conditions (a) and (b)
are met:Once
(a) Engine RPM - target engine RPMLess than -100 rpm, or more than 150 rpm
(b) ISC flow rate learning value1.3 L/sec or less, or 9.03 L/sec 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.
Page 1811 of 2572
- DIAGNOSTICSSFI SYSTEM (3MZ-FE)
05-589
779 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
1 CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0505)
(a) Read the DTC using the hand-held tester or the OBD II scan tool.
Result:
Display (DTC Output)Proceed to
Only P0505 is outputA
P0505 and other DTCs are outputB
HINT:
If any other codes besides P0505 are output, perform the troubleshooting for those codes first.
B GO TO RELEVANT DTC CHART
(See page 05-412)
A
2 CHECK CONNECTION OF PCV HOSE
OK: PCV hose is connected correctly. And PCV hose has no damage.
NG REPAIR OR REPLACE PCV HOSE
OK
3 CHECK AIR INDUCTION SYSTEM
(a) Check for vacuum leaks in air induction system.
OK: No leak in air induction system.
NG REPAIR OR REPLACE AIR INDUCTION SYSTEM
OK
CHECK ELECTRONIC THROTTLE CONTROL SYSTEM (See page 10-12)
Page 1812 of 2572

A82389
Idle Engine
RPM
Small Target RPM
Actual Idle RPMLarge
Learning Value
of the Idle Speed
ControlMaximum
Minimum
Time 0
Time 05-226
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
416 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DTC P0505 IDLE AIR CONTROL SYSTEM
MONITOR DESCRIPTION
The idle speed is controlled by the Electronic Throttle Control System (ETCS).
The ETCS is composed of the throttle motor, which operates the throttle valve, and the throttle position sen-
sor, which detects the opening angle of the throttle valve.
The ECM controls the throttle motor to provide the proper throttle valve opening angle to obtain the target
idle speed.
The ECM regulates the idle speed by opening and closing the throttle valve using the ETCS. The ECM con-
cludes that the idle speed control ECM function is malfunctioning if: 1) the actual idle RPM varies more than
the specified amount five times or more during a drive cycle, or 2) a learning value of the idle speed control
remains at the maximum or minimum five times or more during a drive cycle. The ECM will turn on the MIL
and set a DTC.
Example:
If the actual idle RPM varies from the target idle RPM by more than 200*
1 rpm five times during a drive cycle,
the ECM will turn on the MIL and will set a DTC.
*
1: RPM threshold varies with engine load.
DTC No.DTC Detection ConditionTrouble Area
P0505Idle speed continues to vary greatly from target speed
Electronic throttle control system
Air induction system
PCV hose connection
05EVL-05
Page 1813 of 2572

- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
05-227
417 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
MONITOR STRATEGY
Related DTCsIAC Functional Check
Required sensors / components (Main)ETCS (Electrical throttle control system)
Required sensors / components (Related)CKP sensor, ECT sensor, and VSS
Frequency of operationContinuous
Duration10 min.
MIL operation2 driving cycles
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
The monitor will run whenever this DTC is not presentSee page 05-16
EngineRunning
TYPICAL MALFUNCTION THRESHOLDS
Either of the Conditions is met:Condition 1 or 2
1. Frequency that both of the following conditions (a) and (b)
are met:5 times
(a) Engine RPM - Target engine RPMLess than -100 rpm or more than 150 rpm
(b) Vehicle conditionStop after vehicle was driven at 10 km/h (6.25 mph) or more
2. Frequency that both of the following conditions (a) and (b)
are met:Once
(a) IAC flow rate learning valueBelow 1.3 L/second or above 4.51 L/second
(b) Engine RPM - Target engine RPMLess than -100 rpm or more than 150 rpm
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.
Page 1814 of 2572
05-228
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
418 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
1 CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0505)
(a) Read the DTC using the hand-held tester or the OBD II scan tool.
Result:
Display (DTC Output)Proceed to
Only P0505 is outputA
P0505 and other DTCs are outputB
HINT:
If any other codes besides P0505 are output, perform the troubleshooting for those codes first.
B GO TO RELEVANT DTC CHART
(See page 05-48)
A
2 CHECK CONNECTION OF PCV HOSE
OK: PCV hose is connected correctly and PCV hose has no damage.
NG REPAIR OR REPLACE PCV HOSE
OK
3 CHECK AIR INDUCTION SYSTEM
(a) Check for vacuum leaks in the air induction system.
OK: No leak in air induction system.
NG REPAIR OR REPLACE AIR INDUCTION SYSTEM
OK
CHECK ELECTRIC THROTTLE CONTROL SYSTEM (See page 10-1)
Page 1815 of 2572

- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
05-229
419 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DTC P0560 SYSTEM VOLTAGE
MONITOR DESCRIPTION
The battery supplies electricity to the ECM even when the ignition switch is OFF. This electricity allows the
ECM to store data such as DTC history, freeze frame data, fuel trim values and other data. If the battery
voltage falls below a minimum level, the ECM will conclude that there is a fault in the power supply circuit.
The next time the engine starts, the ECM will turn on the MIL and a DTC will be set.
DTC No.DTC Detection ConditionTrouble Area
P0560Open in ECM back-up power source circuit
(1 trip detection logic)Open in back-up power source circuit
ECM
HINT:
If DTC P0560 is present, the ECM will not store other DTCs.
MONITOR STRATEGY
Related DTCsP0560: ECM system voltage
Required sensors / components (Main)ECM
Required sensors / components (Related)-
Frequency of operationContinuous
Duration3 sec.
MIL operationImmediate (MIL will illuminate after the next engine start)
Sequence operationNone
TYPICAL ENABLING CONDITIONS
The monitor will run whenever this DTC is not presentSee page 05-16
TYPICAL MALFUNCTION THRESHOLDS
ECM power sourceLess than 3.5 V
05EVM-05
Page 1816 of 2572
A90302
BATTECM
F7
FL Block Assy 32IEFI NO. 13
E5
11
BR
Battery1
E9
FL
MainE1 BR
A
A
BR
EE WEngine Room J/B
J7
J/C W
2B7
IK211
B-W
A90343EFI NO. 1 fuse Engine Room J/B
05-230
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
420 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
WIRING DIAGRAM
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.
1 INSPECT FUSE (EFI NO. 1)
(a) Remove the EFI NO. 1 fuse from the engine room J/B.
(b) Measure the resistance of the EFI NO. 1 fuse.
Standard: Below 1 W
OK REPLACE FUSE
OK