NAG 1 Performance Issues

2011 Dodge Challenger and Nitro vehicles equipped with the NAG 1 transmission (same as the 722.6 used in Mercedes) may set codes P0730 for Incorrect Gear Ratios and P0219 for Engine Overspeed along with a variety of customer concerns.

Reprogramming the computer will resolve these concerns including a variety of drivability issues and transmission improvements.

Manufacturer Bulletin Number 18-020-11

Drivability Improvements:

1. At a light throttle tip in (2 to 6 percent) the RPM may oscillate slightly (+/-200 rpm). If the throttle tip in is increased then the issue is not present
2. Lacks Performance. Some driving conditions can produce circumstances where some customers may perceive more pedal effort is required to get the Powertrain to accelerate the vehicle as desired. The PCM calibration for pedal vs. torque relationship was changed to allow for more torque delivery at less pedal effort/travel. In accordance with this PCM calibration change, the PCM was re-calibrated to provide optimal performance and fuel economy. The combined PCM and TCM software improvements will translate into a feeling of improved performance to the driver.
3. Customer describes a temporary "Loss of Power" event due to the transmission going to Neutral during a heavy throttle 4-3 downshift. This may happen when driving at moderate speed, 35 to 70 MPH (56 to 112 KPH) when the driver accelerates with pedal input from 40-100 percent triggering a 4-3 downshift. This may set the P0730 - Incorrect Gear Ratio DTC along with the MIL light ON and cause a Neutral condition within the transmission. This will typically be described as a "Loss of Power" complaint. The MIL for the P0730 will clear after 3 consecutive ignition cycles without setting another P0730 DTC. The P0730 DTC will remain stored in the PCM for 40 consecutive "good" ignition cycles and then be cleared. To correct this condition the TCM pressure control and torque management were re-calibrated improving the 4-3 downshift control during these conditions.

Transmission Improvements:

1. Lack of performance feeling during low vehicle speed turning or cornering maneuvers. To correct this condition a new TCM feature was developed to detect when the vehicle is in a turn and will then not perform an up-shift.
2. Harsh 3-4-3 change mind shift. This happens when driving at moderate speed of 30 to 50 mph (48 to 80 kmh) when the driver reduces accelerator pedal input to 5-10 percent The TCM then schedules a 3-4 up-shift. When the driver accelerates rapidly, pedal input from 40-100 percent will CANCEL the 3-4 up-shift and trigger a "change mind" shift and revert back to 3rd gear. The TCM "change mind" pressure control and torque management were re-calibrated to smooth the shift control during this maneuver.
3. Noticeable higher engine RPM during low speed driving. This condition will be noticed during parking lot or city traffic low speed driving. The TCM logic was refined to keep the up-shift inhibit more linear vs. vehicle speed.
4. Transmission not shifting into next higher gear while driving up or down hills or while driving at high altitude. The TCM logic has been changed to compensate for these two conditions. (LC 3.6L Only).
5. Down shift bumps while driving between 35 to 70 MPH (56 to 112 KPH) and the driver performs a wide open throttle (WOT). The TCM logic was optimized to smooth out the 5-2 and 4-2 downshifts during a WOT condition (LC 3.6L Only).

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