PCM/ECM sets DTC P0638 if the PCM/ECM detects TPS adaptation value exceeds threshold value.
Item | Detecting Condition | Possible Cause | |
DTC Strategy | Case1 |
•
TPS adaptation condition check | 1. Poor connection or damaged harness 2. Faulty ETC Motor 3. Faulty TPS |
Case2 |
•
ETC Limp Home position check | ||
Case3 |
•
Lower mechanical stop adaptation voltage range check | ||
Enable Conditions |
•
During TPS adaptation | ||
Threshold Value | Case1 |
•
TPS adaptation is requested but not possible | |
Case2 |
•
Difference between Throttle sensor voltage in limphome and limphome setpoint > 0.3V | ||
Case3 |
•
Difference between Throttle sensor voltage in lower mechanical stop position and lower mechanical stop position setpoint > 0.3V | ||
Diagnostic Time |
•
1.2 sec. | ||
Limp-Home |
•
Forced limited RPM mode : The PCM limits engine speed to 1500rpm
•
Electrical check of the ETC system is prohibited | ||
MIL On Condition |
•
Immediate | ||
