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. TPS1&2 are sharing the same source voltage and ground.The throttle valve opening is control by throttle motor which is controlled by Engine Control Module(ECM).The opposite position indicator shows inverted signal characteristics.TPS1 output voltage increases smoothly in proportion with the throttle valve opening angle after starting. TPS2 output voltage decreases in inverse proportion with the throttle valve opening angle after starting. TPS 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 output signals from TPS1 every 8.5 sec. under detecting condition, if an output signal is above 4.75V for more than 0.1 sec., PCM sets P0123. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
Item | Detecting Condition | Possible Cause | ||||||
DTC Strategy | ● signal high | ● Poor connection ● Open or short to battery in signal harness ● Open in ground harness ● TPS ● PCM | ||||||
Enable condition | ● IG "ON | |||||||
threshold value | ● The voltage of TPS 〉4.75V | |||||||
diagnosis time | ● Continuous (more than 0.1 sec. failure for every 8.5 sec.test) | |||||||
MIL ON condition | ● 2 driving cycles |
Throttle opening ( ° ) | Output voltage(V) [Vref=5.0] | |
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 "Terminal and connector 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.
Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure
▶ Go to "Signal Circuit Inspection" procedure.
Check voltgae
IG "OFF" and disconnect TPS connector.
IG "ON" and ENG "OFF"
Measure voltage between terminal 2 of TPS harness connector and chassis ground.
Specification : Approx. 5V
Is the measured voltage within specification?
▶ Go to "Check short to battery in harness" as follows.
▶ Go to "Check open in harness" as follows.
Check open in harness
IG "OFF" and disconnect TPS connector and PCM connector.
Measure resistance between terminal 2 of TPS harness connector and terminal 48 of PCM harness connector.
Specification : Below 1Ω
Is the measured resistance within specification?
▶ Go to "Ground Circuit Inspection" procedure.
▶ Repair open in harness, and go to "Verification of Vehicle Repair" procedure.
Check short to battery in harness
IG "OFF" and disconnect TPS connector and PCM connector.
Measure resistance between terminals 4 and 2 of TPS harness connector.
Measure resistance between terminals 7 and 2 of TPS harness connector.
Measure resistance between terminals 5 and 2 of TPS harness connector
Measure resistance between terminals 8 and 2 of TPS harness connector.
Specification : Infinite
Is the measured resistance within specification?
▶ Go to "Ground circuit inspection " procedure.
▶ Repair short to battery in harness, and go to "Verification of Vehicle Repair" procedure.
IG "OFF" and disconnect TPS connector.
IG "ON" and ENG "OFF"
Measure voltage between terminal 4 of TPS harness connector and chassis ground.
Measure voltage between terminals 4 and 1 of TPS harness connector.
Specification : Voltage difference between measurement "A" and "B" is below 200mV.
Is the measured voltage within specification?
▶ Go to "Component inspection" procedure.
▶ Repair open or contact resistance in harness, and go to "Verification of Vehicle Repair" procedure.
Check TPS
IG "OFF" and disconnect TPS connector.
Measure resistance between terminals 4 and 1 of TPS connector.(component side)
Specificaton : 4 ~ 6kΩ
Is the measured resistance within specification?
▶ Substitute with a known - good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.
▶ Substitute with a known - good ECT motor & TPS and check for proper operation. If the problem is corrected, replace ECT motor & TPS and go to "Verification of Vehicle Repair" procedure.
Procedure of ETS Initialization
Erase the trouble codes on PCM
Turn the ignition key off and keep this condition until the main relay is turned off.(It will takes 10sec.)
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.
Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode
Press F4(DTAL) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions
Read "DTC Status" parameter
Is parameter displayed "History(Not Present) fault"?
▶ System performing to specification at this time. Clear the DTC.
▶ Go to the applicable troubleshooting procedure.