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 |
