If the difference between real and target throttle position is abnormal, the ECM sets DTC P0638.
Item | Detecting Condition | Possible Cause | |
Case 1 | DTC Strategy |
•
Return Spring Check | 1. Throttle stuck 2. Open in motor circuit 3. Faulty motor 4. Faulty ECM |
Enable Conditions |
•
During TPS adaptation | ||
Threshold Value |
•
Throttle position > Limp-home pos.+3 % | ||
Diagnostic Time |
•
0.56 sec | ||
MIL ON Condition |
•
1 driving cycle | ||
Case 2 | DTC Strategy |
•
Abnormal value of TPS re-adaptation | |
Enable Conditions |
•
During TPS adaptation (throttle is made to approach the lower mech. throttle limit stop via ramp) Learned value already saved | ||
Threshold Value |
•
Voltage throttle poti 1 at the lower limit stop < 0.21 V or Voltage throttle poti 2 at the lower limit stop > 4.84 V or Volt. sum throttle poti1 and 2 = 5 V | ||
Diagnostic Time |
•
0.3 sec | ||
MIL ON Condition |
•
1 driving cycle | ||
Case 3 | DTC Strategy |
•
Abnormal value of TPS re-adaptation | |
Enable Conditions |
•
Delta Limphome(last dcy adaptation - current dcy adaptation) or ETC replaced or ECU reset | ||
Threshold Value |
•
Voltage throttle poti 1 at the lower limit stop + offset > 0.695 V
•
Voltage throttle poti 2 at the lower limit stop - offset(0.025 V) < 4.305 V | ||
Diagnostic Time |
•
0.3 sec | ||
MIL ON Condition |
•
1 driving cycle | ||
Case 4 | DTC Strategy |
•
TPS re-adapation was failed due to violated input conditions | |
Enable Conditions |
•
During TPS adaptation | ||
Threshold Value |
•
Engine speed > 250 rpm
•
Vehicle speed > 0 mph
•
Accel. pedal > 14.9 %
•
ECT < 5.3 ℃(41.54 °F)
•
ECT > 100.5 ℃(212.9 °F)
•
IAT < 5.3 ℃(41.54 °F) | ||
Diagnostic Time |
•
Immediate | ||
MIL ON Condition |
•
2 driving cycles | ||
Case 5 | DTC Strategy |
•
TPS re-adapation was failed due to violated input conditions | |
Enable Conditions |
•
During TPS adaptation | ||
Threshold Value |
•
Engine speed > 250 rpm
•
Vehicle speed > 0 mph
•
Accel. pedal > 14.9 %
•
ECT < 5.3 ℃(41.54 °F)
•
ECT > 100.5 ℃(212.9 °F)
•
IAT < 5.3 ℃(41.54 °F) | ||
Diagnostic Time |
•
Immediate | ||
MIL ON Condition |
•
1 driving cycle | ||
Case 6 | DTC Strategy |
•
TPS adaptation fault or abnormal value during the first initialization | |
Enable Conditions |
•
First initialization
•
IG ON | ||
Threshold Value |
•
Learning stop due to violated input condition and UMA learning error | ||
Diagnostic Time |
•
Immediate | ||
MIL ON Condition |
•
1 driving cycle | ||
Case 7 | DTC Strategy |
•
Limp-home check | |
Enable Conditions |
•
IG ON | ||
Threshold Value |
•
Limp-home position < 1.0% or > 19.5% | ||
Diagnostic Time |
•
Immediate | ||
MIL ON Condition |
•
2 driving cycles |