2001 Dodge Caravan • 173,000 miles

Code P0122 comes on only when I shift trans. Into drive. Runs and shifts fine, but shifts in and out of lock-up with slightest throttle change.
November 26, 2012.

P0122 Throttle/Pedal Position Sensor/Switch A Circuit Low Input

That suggests a break in the 5.0 volt feed wire to the throttle position sensor. Check the connector for stretched or corroded terminals or a break in the 5.0 volt wire. That would be a lot more common than a defective sensor.

The additional dandy clue about the lockup torque converter can be caused by dirt in the throttle position sensor, but that code should be "voltage high". I never like to replace parts until a proper diagnosis confirms they're bad, but in this case, if you don't see a wiring problem, you may want to try a new TPS. First wiggle the wiring harness with the transmission still in park while a helper watches to see if the Check Engine light comes on. If you have a scanner you can also watch the TPS volts to see what causes the voltage to change when you wiggle wire harnesses.

Nov 26, 2012.