The Electronic Throttle Control(ETC) system is made of the components throttle body, Throttle Position Sensor(TPS)1&2 and Accelerator Position Sensor(APS) 1&2. The throttle body contains the actuator, the throttle plate and the throttle position sensor (potentiometer), which are integrated in one housing. The actuator consists of a DC motor with a two-stage gear. The opening angle of the throttle valve is detected by the throttle position sensor which is mounted on the throttle body. And it provides feedback to the ECM to control the throttle motor in order to control the throttle valve opening angle properly in response to the driving condition.
Checking throttle valve return state, under detecting condition, if an output signal is within the threshold value for more than designated time, PCM sets P1523.
Item | Detecting Condition | Possible cause |
DTC Strategy | ● This code detects when throttle fails to return to the unpowered default position when power to the ETC motor is turned off. | ● Carbon in throttle ● Broken Throttle return spring ● throttle sticky ● throttle icy ● PCM |
EnableConditions | ● Throttle Actuation Mode Previous NOT Off ● Throttle Actuation Mode is Off ● ETC Power Control Mode = Normal ● TPS 1 & 2 = normal ● Sensor Supply voltage = Normal | |
Threshold value | ● If throttle did not return to default range within calculated seconds of turning off, increment fail count. | |
DiagnosisTime | ● Continuous | |
MIL On Condition | ● DTC only (NO MIL ON) |
Throttle opening ( ° ) | Output voltage (V) [Vref = 5.0V] | |
TPS1 | TPS2 | |
0° | 0.0V | 5.0V |
10° | 0.5V | 4.5V |
20° | 0.9V | 4.1V |
30° | 1.4V | 3.6V |
40° | 1.8V | 3.2V |
50° | 2.3V | 2.7V |
60° | 2.7V | 2.3V |
70° | 3.2V | 1.8V |
80° | 3.6V | 1.4V |
90° | 4.1V | 0.9V |
100° | 4.5V | 0.5V |
110° | 5.0V | 0.0V |
Check DTC Status
Connect scantool to Data Link Connector(DLC).
IG "ON".
Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F4(DTAL) to check DTC's information from the DTCs menu
Read "DTC Status" parameter.
Is parameter displayed "Present fault"?
▶ Go to "System inspection" procedure.
▶ Fault is intermittent caused by poor contact in the sensor’s and/or PCM’s connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
Visual Inspection
IG "OFF".
Check throttle valve after removing air duct.
Carbon deposit.
Throttle icy
Broken return spring.
Throttle sticky
Is the throttle valve return O.K ?
▶Substitute with a known-good PCM and check for proper operation. If the problem is corrected,replace PCM and then go to "Verification of Vehicle Repair" procedure.
There is a memory reset function on scantool that can erase optional parts automaticallydetected and memorized by PCM.
Before or after testing PCM on the vehicle, use this function to reuse the PCM on the others
▶ Repair or replace as necessary and then, do ETS Initialization" as follows. then, go to "Verification of Vehicle Repair" procedure.
※ Procedure of ETS Initialization
1. Erase the trouble codes on PCM
2. Turn the ignition key off and keep this condition until the main relay is turned off.(It will takes 10sec.)
3. Turn ignition key on more than 1second to record the throttle motor position on the EEPROM
After a repair, it is essential to verify that the fault has been corrected.
Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
Using a Scantool, Clear the DTCs
Operate the vehicle within conditions noted in the freeze frame data or enable conditions
Monitor that all rediness test have been verified as " Complete "
Are any DTCs present ?
▶ Go to the applicable troubleshoooting procedure.
▶ System is performing to specification at this time.