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 APS is mounted in the accelerator pedal to detect the opening angle of the accelerator pedal. It has 2 sensors to detect the accelerator position and a malfunction of the accelerator position sensor. The ECM judges the current opening angle of the accelerator pedal from APS1&2, and the ECM controls the throttle motor based on these signals.
Checking output signals from APS 1, under detecting condition, if output signals are above the threshol, PCM sets P2123 and then MIL(Malfunction Indication Lamp) turns on.
Item | Detecting Condition | Possible Cause | |
DTC Strategy | ● This code detects a short to high in either the circuit or the sensor (0-100%) | ● Poor connection ● Short to battery in Signal Circuit ● Open in Ground Circuit ● Faulty APS ● Faulty PCM | |
Enable Conditions | ● Ignition "ON" | ||
Threshold | ● APS1 〉4.5V | ||
Diagnosis Time | ● Continuous | ||
MIL On Condition | ● 1 Driving Cycle |
Pedal Position | Output Voltage(V) [Vref = 5.0V] | |
APS1 | APS2 | |
C.T | 0.7 ~ 0.8V | 0.275 ~ 0.475V |
W.O.T | 3.8 ~ 4.4V | 1.75 ~ 2.35V |
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 short to battery in harness
IG "OFF".
Disconnect APS and PCM connector.
Measure resistance between terminal 2 and 4 of APS harness connector.
Measure resistance between terminal 2 and 5 of APS harness connector.
Specification : Infinite
Is the measured resistance within specification ?
▶ Go to "Ground Circuit Inspection" procedure.
▶ Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
Check open in harness
IG "OFF".
Disconnect APS connector.
Measure voltage between terminal 4 of APS harness connector and chassis ground.(Fig. A)
Measure voltage between terminal 4 and 5 of APS harness connector.(Fig. B)
Specification : Fig. "A" - Fig. "B" = approx. below. 200mV.
Is the measured voltage within specification ?
▶ Go to "Component Inspection" procedure.
▶ Repair or replace contact resistance or open in harness and then, go to "Verification of VehicleRepair" procedure.
Check APS
Ignition "ON" & ENG "OFF".
Measure waveform of APS by pressing and depressing accellerator pedal with scantool.
Pedal Position | Output Voltage(V) [Vref = 5.0V] | |
APS1 | APS2 | |
C.T | 0.7 ~ 0.8V | 0.275 ~ 0.475V |
W.O.T | 3.8 ~ 4.4V | 1.75 ~ 2.35V |
Is the measured signal waveform 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
▶ Substitute with a known-good APS and check for proper operation. If the problem is corrected,replace APS and then go to "Verification of Vehicle Repair" procedure.
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.