FUNCTION
AND OPERTION PRINCEPLE
The Electronic
Throttle Control (ETC) System consists of a throttle body with an
integrated control motor and throttle position sensor (TPS). Instead of
the traditional throttle cable, an Accelerator Position Sensor (APS) is
used to receive driver input. The ECM uses the APS signal to calculate the
target throttle angle; the position of the throttle is then adjusted via
ECM control of the ETC motor. The TPS signal is used to provide feedback
regarding throttle positon to the ECM. Using ETC, precise control over
throttle position is possible; the need for external cruise control
modules/cables is eliminated.
COMPONENTS
SPECIFICATION
[THROTTLE POSITION SENSOR]
Throttle
Angle(°)
|
Output
Voltage(V) [Vref = 5.0V]
|
TPS1
|
TPS2
|
0°
|
0
|
5.0
|
10°
|
0.5
|
4.5
|
20°
|
0.9
|
4.1
|
30°
|
1.4
|
3.6
|
40°
|
1.8
|
3.2
|
50°
|
2.3
|
2.7
|
60°
|
2.7
|
2.3
|
70°
|
3.2
|
1.8
|
80°
|
3.6
|
1.4
|
90°
|
4.1
|
0.9
|
100°
|
4.5
|
0.5
|
110°
|
5.0
|
0
|
Item
|
Sensor
Resistance
|
TPS1
|
4.0 ~ 6.0kΩ at 20°C (68°F)
|
TPS2
|
2.72 ~ 4.08kΩ at 20°C
(68°F)
|
[ETC MOTOR]
Item
|
Sensor
Resistance
|
Coil Resistance (Ω)
|
1.275 ~ 1.725Ω at 20°C
(68°F)
|
SCHEMATIC
DIAGRAM
FAIL-SAFE
MODE
Mode
|
Description
|
Symptom
|
Possible
Cause
|
MODE 1
|
FORCED ENGINE SHUTDOWN
|
Engine stop
|
| •
|
ETC system can't proceed reliable
algorithm procedure |
| - |
Fatal PCM internal programming
error |
| - |
Faulty intake system or throttle
body | | |
MODE 2
|
FORCED IDLE & POWER MANAGEMENT
|
Forced idle state controlled by fuel quantity
regulation and ignition timing adjustment
|
| •
|
ETC system can't control engine power
via throttle device |
| •
|
Disabled throttle control or broken
throttle position
information | |
MODE 3
|
FORCED IDLE
|
Forced idle state and no response for accelerator
activation
|
| •
|
No information about the accelerator
position |
| - |
Broken APS 1 and 2, faulty A/D
converter or internal
controller | | |
MODE 4
|
LIMIT PERFORMANCE & POWER MANAGEMENT
|
Engine power is determined by accelerator position and
idle power requirement (Limited vehicle running)
|
| •
|
ETC system can't securely control
engine power | |
MODE 5
|
LIMIT PERFORMANCE
|
| 1. |
Engine power varies with accelerator
position, but driver perceives lack of engine
power. |
| 2. |
MIL ON (Normal vehicle
running) | |
| •
|
Not reliable accelerator position
signal or bad maximum power
generation |
| - |
Faulty APS, ignition voltage or
internal
controller | | |
MODE 6
|
NORMAL
|
Normal
|
|
COMPONENT
INSPECTION
THROTTLE POSITION
SENSOR (TPS)
| 1. |
Connect a scantool on the Data Link
Connector (DLC). |
| 2. |
Start engine and check output voltages of
TPS 1 and 2 at C.T and W.O.T.
Specification: Refer to
SPECIFICATION.
| |
| 3. |
Turn ignition switch OFF and disconnect the
scantool from the DLC. |
| 4. |
Disconnect ETC module connector and measure
resistance between ETC module terminals 4 and 8 (TPS
1). |
| 5. |
Measure resistance between ETC module
terminals 1 and 5 (TPS 2).
Specification: Refer to
SPECIFICATION.
| |
ETC
MOTOR
| 1. |
Disconnect ETC module connector and measure
resistance between ETC module terminals 2 and 3.
Specification: Refer to
SPECIFICATION.
| |
ETC
SYSTEM INITIALIZATION
| 1. |
Erase the trouble codes on
ECM |
| 2. |
Turn the ignition key off and keep this
condition until the main relay is turned off.(10
sec.) |
| 3. |
Turn ignition key on more than 1second to
record the throttle motor position on the
EEPROM |
