The Electronic Throttle Control(ETC) system consists of the throttle body, Throttle Position Sensor(TPS)1&2 and Accelerator Position Sensor(APS) 1&2. The ECM controls the throttle motor to open and close the throttle valve. The 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 driver's demands. The APS is mounted on the accelerator pedal assembly to to send the driver's demand to the ECM. It has 2 sensors to detect the accelerator position. The ECM uses the signals from APS1&2, and controls the throttle motor based on these signals.
Checking output signals from APS 1 and 2 under detecting condition, if output signals difference between APS 1 and 2 are detected more than 4.5% for the specified number of times., ECM sets P2138.
Item | Detecting Condition | Possible cause |
DTC Strategy |
•
This code detects a correlation error between APS 1 and APS 2. |
•
Poor connection
•
Open or short in APS circuit
•
Faulty APS
•
Faulty ECM |
Enable Conditions |
•
Ignition "ON" | |
Threshold value |
•
Difference between APS1 and APS2 Normalized values > 4.5% | |
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 | 0.29 ~ 0.46V |
W.O.T | '3.85 ~ 4.35V | 1.93 ~ 2.18V |
Fig.1) Normal waveform of APS1 & APS2 with no acceleration
Fig.2) Normal waveform of APS1 & APS2 with acceleration
Fig.3) Normal data of APS1 & APS2 at ig on.
Fig.4) Abormal data of APS1 & APS2 when APS1 & APS2 circuit open
Signal waveform of APS 1 & 2 shows that APS 2 increases voltage just half of APS 1 voltage increase when accelerating.
