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.
PCM sets DTC P2138 if the PCM detects output voltage of the APS1 is not proportion to APS2.
Item
Detecting Condition
Possible Cause
DTC Strategy
Plausibility check
Poor connection or damaged harness
APS1
APS2
Enable Conditions
No relevant failure
APS1 >1.0V or APS2 >0.55V
Threshold Value
Ratio check between pedal sensor channel 1and 2
Diagnostic Time
0.35sec.
MIL On Condition
Immediate
Limp-Home
Forced limited power mode : The PCM limits opening angle of the throttle valve to max. 50% and engine torque to a certain pre-determined value.
The PCM selects the current opening angle of the throttle valve from minimum value of APS1 and APS2.