I have a 2002 Nissan Maxima which which started exhibiting a number of transmission issues shortly before and during a 2,600 mile road trip across the country, and is still experiencing these problems; the issues displayed are as follows:
- Two DTCs are stored in the PCM - P1574 "(ACSD) Vehicle Speed Sensor" and P0720 "AT Vehicle Speed Sensor."
- The "AT CHECK" warning lamp will flash several times for approximately 10 seconds when first starting the vehicle or turning the key to ignition "ON."
- The cruise control is barely operational; after shutting off the car and restarting it, it will work for about 20 minutes before disengaging and flashing the cruise control indicator. Oftentimes it will simply not work at all.
- At cruising speeds 70 MPH - 90 MPH the vehicle will sometimes experience a light "shudder," as though the whole vehicle is shaking forward & backwards.
- At speeds between 90 MPH - 110 MPH the transmission will, at random, occasionally neutralize for a half second, then downshift into 3rd or 2nd gear (not all the time), and then return to OD; this occurs particularly under heavy throttle, during passing or when ascending on a long incline.
- At low speeds, particularly after an extended period of highway driving, the transmission will not shift out of 1st gear.
Based on the research I have done in the factory service manual, it appears that the primary culprits could be as follows: the revolution sensor, located on the driver side of the vehicle and accessible through the wheel well; an issue with the sensor harness or connectors; a TCM failure; or mechanical failure of the parking pawl lock / idler gear, the revolution of which the preceding sensor detects (doesn't seem likely to me - the parking pawl engages fine).
It should be noted that the speedometer is still fully operational and displaying the correct vehicle speed.
Thus I have two questions: besides what is listed above, are there any other systems or components which I should inspect for diagnosis which could set the above DTCs and cause the above issues? Additionally, I had no choice but to drive the vehicle in this condition approximately 2,600 miles across the country due to an emergency situation - could I have caused any mechanical damage to the transmission, what form would this damage take, and how could I go about ascertaining whether any has occurred?