The APS is a very important sensor which controls the fuel amount by transmitting the driver's accelerating intention to ECM. And it is divided into APS 1,2 because its reliability is important. The APS 1,2 are composed with the independent power and ground. APS 2 shows the 1/2 output of the APS1 and decides the fault if the ratio of APS 1,2 is different. When the APS 1 is out of order, the signal of APS 2 can be substituted instead of APS 1 and vise versa.
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 |
•
Plausibility check between pedal value sensor 1, 2 | 1. Poor connection 2. Open or short in APS circuit 3. Faulty APS 4. Faulty ECM |
Enable Conditions |
•
After Eng. Start | |
Threshold Value |
•
I (APS1/2) –APS2 I > Threshold f(Eng. rpm) | |
Diagnostic Time |
•
0.16 sec | |
MIL ON Condition |
•
5 sec |
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.
