The APS is a very important sensor which controls the fuel amount by transmitting the driver's accelerating intention to ECM/PCM. 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 under detecting condition, if output signals are above the threshold, ECM/PCM sets P2123.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Signal check, high | 1. Poor connection 2. Short to battery in signal circuit 3. Open in ground circuit 4. Faulty APS 5. Faulty ECM/PCM |
Enable Conditions |
•
Ignition "ON" | |
Threshold Value |
•
APS1 > 4.8V | |
Diagnostic Time |
•
0.2 sec | |
MIL ON Condition |
•
Immediately |
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.
