Technical Bulletin # TCB5
Subject: Cycling In & Out of Lockup
Issue Date: November, 2010
TCC Cycling In & Out
Dodge and Jeep vehicles with an RE type transmission and a complaint of TCC cycling in and out between 40-50 mph may be caused by Electro Magnetic Interference (EMI).
Use your scan tool to verify the command being sent by the PCM. If the PCM is commanding the TCC to cycle the problem may be caused by Electro Magnetic Interference (EMI) from the Alternator. To test this unbolt the wire from the battery positive at the alternator (not necessary to unplug the Field Wire). This test can only be performed for a short time while the problem is present.
The first step would be to clean both Battery Terminal Connections (both Batteries on Diesel vehicles) no matter how clean they may appear (replace Battery Cables if needed). Remove the ground cable connection on the engine block and clean the contact surface area (most common fault). This procedure should be done before replacing the Alternator along with testing for a faulty Diode.
There is a common fix for an EMI problem by installing a Noise Filter on the Throttle Position (TPS) or Accelerator Pedal Position Sensor (APPS) circuit to the Powertrain Control Module (PCM) (figure 1). A noise filter can be purchased through aftermarket suppliers or substituted by making your own filter (figure 2).
On page 3 is a list of several causes for the same complaint. This list is compiled from many years of technical hotline calls on causes and fixes for this complaint which include both gas and diesel engines. Some are specific to gas and/or diesel engines in the order of most common.
View PDF for entire Technical Bulletin.
Click here to view a PDF of this Technical Bulletin