P0123

COMPONENT LOCATION





GENERAL DESCRIPTION

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.

DTC DESCRIPTION

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.

DTC DETECTING CONDITION





SIGNAL WAVEFORM AND DATA





SPECIFICATION





SCHEMATIC DIAGRAM





MONITOR DTC STATUS

1. Check DTC Status
(1) Connect scantool to Data Link Connector(DLC).
(2) IG "ON".
(3) Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F4(DTAL) to check DTC's information from the DTCs menu
(4) Read "DTC Status" parameter.




(5) Is parameter displayed "Present fault"?
YES
> Go to "Terminal and connector inspection" procedure.
NO
> 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.

TERMINAL AND CONNECTOR INSPECTION

1. 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.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES
> Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
> Go to "Signal Circuit Inspection" procedure.

SIGNAL CIRCUIT INSPECTION

1. Check voltgae
(1) IG "OFF" and disconnect TPS connector.
(2) IG "ON" and ENG "OFF"
(3) Measure voltage between terminal 2 of TPS harness connector and chassis ground.

Specification : Approx. 5V





(4) Is the measured voltage within specification?
YES
> Go to "Check short to battery in harness" as follows.
NO
> Go to "Check open in harness" as follows.
2. Check open in harness
(1) IG "OFF" and disconnect TPS connector and PCM connector.
(2) Measure resistance between terminal 2 of TPS harness connector and terminal C201-2 (48) of PCM harness connector.

Specification : Below 1Ohms





(3) Is the measured resistance within specification?
YES
> Go to "Ground Circuit Inspection" procedure.
NO
> Repair open in harness, and go to "Verification of Vehicle Repair" procedure.
3. Check short to battery in harness
(1) IG "OFF" and disconnect TPS connector and PCM connector.
(2) Measure resistance between terminals 4 and 2 of TPS harness connector.
(3) Measure resistance between terminals 7 and 2 of TPS harness connector.
(4) Measure resistance between terminals 5 and 2 of TPS harness connector.
(5) Measure resistance between terminals 8 and 2 of TPS harness connector.

Specification : Infinite





(6) Is the measured resistance within specification?
YES
> Go to "Ground circuit inspection " procedure.
NO
> Repair short to battery in harness, and go to "Verification of Vehicle Repair" procedure.

GROUND CIRCUIT INSPECTION

1. IG "OFF" and disconnect TPS connector.
2. IG "ON" and ENG "OFF"
3. Measure voltage between terminal 4 of TPS harness connector and chassis ground.
4. Measure voltage between terminals 4 and 1 of TPS harness connector.

Specification : Voltage difference between measurement "A" and "B" is below 200mV.





5. Is the measured voltage within specification?
YES
> Go to "Component inspection" procedure.
NO
> Repair open or contact resistance in harness, and go to "Verification of Vehicle Repair" procedure.

COMPONENT INSPECTION

1. Check TPS
(1) IG "OFF" and disconnect TPS connector.
(2) Measure resistance between terminals 4 and 6 of TPS connector.(component side)

Specificaton : 4 - 6kOhms





(3) Is the measured resistance within specification?
YES
> 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.
NO
> 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.

CAUTION:
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

VERIFICATION OF VEHICLE REPAIR

After a repair, it is essential to verify that the fault has been corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions
4. Monitor that all rediness test have been verified as " Complete "
5. Are any DTCs present ?
YES
> Go to the applicable troubleshoooting procedure.
NO
> System is performing to specification at this time.