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 PCM judges the current opening angle of the accelerator pedal from APS1&2, and the PCM controls the throttle motor based on these signals.
Checking output signals from APS 2 under detecting condition, if output signals are below the threshold, PCM sets P2127.
Item
Detecting Condition
Possible Cause
DTC Strategy
Signal check, low
Poor connection
Open or short to ground in power circuit
Open or short to ground in signal circuit
Faulty APS
Faulty PCM
Enable Conditions
Ignition "ON"
Threshold value
APS2 > 0.312V
Diagnosis Time
0.14 sec
MIL On Condition
1 Driving Cycle
Pedal Position
Output Voltage(V) [Vref = 5.0V]
APS1
APS2
C.T
0.7 ~ 0.8V
0.29 ~ 0.46V
W.O.T
3.85 ~ 4.35V
1.93 ~ 2.18V
Fig.1) Normal waveform of APS1 & APS2 with acceleration
Signal waveform of APS 1 & 2 shows that APS 2 increases voltage just half of APS 1 voltage increase when accelerating.