DTC | P1639 | A/D Converter Monitoring Malfunction |
An ECM ROM(A) malfunction is detected by using a checksum technique for verifying data. Digital data is composed of zeros and ones. A checksum is the total of all ones in a string of data. By comparing the checksum value with a stored value, a malfunction can be detected.
DTC No | Detecting Condition & Limp Home | Suspected area |
P1639 | Detecting Condition The ground check of APS (acceleration position sensor)2 is error. The reference voltage of A/D converter is error. Dynamic RAM-test is failed. Enable Condition Ignition switch : ON Limp Home Engine speed is fixed at 1200rpm | - ECM |
● Internal fault. There is no inspection of service possible for this diagnostic trouble code. ● Temporarily install a good ECM and check for proper operation. If problem is corrected, replace ECM. |
