Nitro 2WD V6-4.0L (2007)
Control Module: Customer Interest
Engine, A/T Controls - MIL ON/DTC P0741 Set
NUMBER: 18-011-10
GROUP: Vehicle Performance
DATE: April 13, 2010
THE wiTECH DIAGNOSTIC APPLICATION IS THE PREFERRED METHOD FOR FLASHING ECUs. HELP USING THE wiTECH
DIAGNOSTIC APPLICATION FOR FLASHING AN ECU IS AVAILABLE BY SELECTING "HELP" THEN "HELP CONTENTS" AT THE TOP
OF THE wiTECH DIAGNOSTIC APPLICATION WINDOW.
THE wiTECH SOFTWARE LEVEL MUST BE AT RELEASE 10.03 OR HIGHER TO PERFORM THIS PROCEDURE.
StarMOBILE DESKTOP CLIENT MAY ALSO BE USED TO PERFORM THIS PROCEDURE.
SUBJECT:
Flash: Shift Improvements And/Or Transmission Temp Light Illuminated When No Problem Exists And/Or MIL Illumination P0741 - Torque Converter
Clutch Circuit Performance
OVERVIEW:
This bulletin involves selectively erasing and reprogramming the Powertrain Control Module (PCM) and Transmission Control Module (TCM) with new
software. The flash is a combination flash that will update both controllers.
MODELS:
2007 - 2008
(KA)
Nitro
NOTE:
This bulletin applies to vehicles equipped with a 4.0L engine and a NAG1 transmission (Sales Code EGS and DGJ)
SYMPTOM/CONDITION:
MIL Illumination:
The customer may experience a MIL illumination. Upon further investigation the Technician may find that P0741 - Torque Converter Clutch Circuit
Performance has been set.
This is caused by the logic in the TCM that detects torque converter slippage, by design the logic lowers engine torque when excessive slip is detected.
The TCM logic was changed to minimize the amount of torque reduction to the engine as well as the amount of time the logic can reduce torque.
Transmission Temp Light Illuminated When No Problem Exists:
This condition can occur when the shift lever is quickly moved into Park from the Drive or Reverse position. When moving the shift lever from one
position to another, a momentary state change of the reed switch in the transmission can cause an artificially high temperature to be detected by the TCM
.
The TCM software was changed to hold onto the last good temperature reading for two seconds after the shift lever has been moved.
Shift Improvements:
A. The transmission exhibits harsh or abrupt shifting. This can occur when the vehicle is accelerated using moderate to heavy throttle input, and the
pedal is released or the driver "lift's foot off accelerator which allows the transmission to upshift into the next higher gear at closed throttle.
The TCM software was changed to detect this condition and lower the amount of clutch pre-fill.
B. The transmission shifts abruptly during normal driving after the vehicle has been parked for a prolonged period (more than eight hours). The
condition is more noticeable when ambient temperatures are below 40° F (40 C).
The TCM software was changed to allow more flexibility at cold transmission fluid temperatures. The shifts were then re-calibrated for optimal pressure
control during shifts at cold fluid temperatures.
C. Improved Vehicle engagement into Drive or Reverse from another gear position when rolling.
The TCM software was revised to improve engagement when the vehicle is rolling and also to give more flexibility to tailor gear engagements.
