Continuity Conundrum

We spend a great deal of time helping installers with electronic-circuit codes for shift solenoids, PC-solenoid codes, input and output speed sensors, and pressure switches. Nearly all vehicles have issues with circuit codes. The focus of this article will be on Chrysler transmissions, as they seem to have more of these types of concerns than other vehicles. Two- and three-pin harness connectors have been used for quite some time, and they have always been a primary source of circuit problems. The issues with them seem to be getting more prevalent since the vehicles that use them are aging. Loose pin fit and corrosion are the primary causes found with them, and cleaning with a heavy base (baking soda, for example) and a mild steel brush will usually dissolve the corrosion.

R&R Tech

Subject: Preventing connection problems during installation
Units: Chrysler 44RE, 40/41TE, 604, 42RLE, RFE
Essential Reading: Diagnostician, R & R
Author: Jim Stokes

Two- and three-pin harness connectors have been used for quite some time, and they have always been a primary source of circuit problems. The issues with them seem to be getting more prevalent since the vehicles that use them are aging. Loose pin fit and corrosion are the primary causes found with them, and cleaning with a heavy base (baking soda, for example) and a mild steel brush will usually dissolve the corrosion.

Resizing of the female pins to get good pin fit produces better continuity through the circuit. Using a good layer of dielectric grease on the terminals is usually all that is needed to protect the pins from future corrosion. In some instances, a connector cannot be brought back to operating condition. Since aftermarket replacement connectors may be difficult to obtain, a salvaged vehicle connector may need to be used as a replacement. If this is the case, performing the previously mentioned steps before installing the connector to the vehicle will help prevent a comeback.

The eight-pin harness connector used in the 44RE-style transmissions has a few issues also and should be inspected closely. We have had several claims where the insulation just crumbles and falls off the wires, causing shorts to voltage and to ground, and cross-connecting. The connector itself is also prone to corrosion and poor continuity. Both OE and aftermarket replacement connectors are readily available to repair this problem.

The most-troublesome connector seems to be on the 40/41TE units. The solenoid connector and the speed-sensor connections can really be trouble. In addition to codes being present, the poor connections will put the TCM in default and allow only second gear forward. The transmission will stay in this condition until the ignition is cycled and the problem isn’t present. The next occurrence will return the unit to failsafe. These issues are often intermittent and difficult to pinpoint.

The problem starts when the harness connector is removed from the transmission during R&R. When initially installed from the factory, the connector is bolted in and rarely disturbed. This causes the connector to be difficult to remove as a result of corrosion over time. The installer then rocks the connector back and forth to loosen it from the solenoid pack. This causes the pins to spread and become distorted, so the chances of getting good continuity through the replacement solenoid-pack connector are diminished considerably. To resize the pins the connector requires disassembly. This can be done successfully, but we recommend replacement of the connector, as it is readily available through the aftermarket. Chrysler no longer has this connector available.

The 604 speed-sensor connectors are also very troublesome, and loss of a clean connection will cause the TCM to go into failsafe mode and allow only second gear forward. The early-style sensors were replaced with the late-style sensors in August 1998, so any vehicle built prior to that date will require the new sensors and updated harness connectors. When contacted by the customer for this concern, we often find that the package of new harness connectors we sent is supporting a cup of coffee instead of installed on the vehicle, where they belong. The early connectors will plug into the late sensors but will have a poor connection, as the design and size of the pins are different. If the installer is not aware of the issue, he/she may not feel the need to install the correct harness connectors.

The 42RLE units have a factory TSB (21-009-05) for the solenoid-pack harness connector being contaminated with moisture and corrosion. Chrysler has replacement connectors available with part numbers listed in the TSB.

The primary cause of concern with the RFE series of transmissions is the harness connector also, as the locking mechanism is prone to breakage. Ron Clark wrote an article about it in the December 2010 issue of Transmission Digest explaining the problem in great detail. Figures 1 and 2 show where the damage takes place and how to prevent it:

The highlighted area of the connector is where the breakage of the connector takes place.

After you unlock the sliding latch of the harness connector, depressing the highlighted area of the connector will release the harness from the solenoid-pack connector.

Numerous articles have been written to address different types of contamination and wear that can occur to vehicle connectors. The electronic systems throughout any modern vehicle require clean, resistance-free connection to prevent codes, lights and failsafe modes. The important thought to take away from this article is be sure to address all the connectors during your R&R. You can create new issues during the installation or overlook existing issues that may have led to the failure. Either way, taking care to correct these problems will produce a happy customer and reduced comebacks.

Jim Stokes is a warranty technician with Certified Transmission. He has been a service writer and diagnostician, has helped run stores and has been a part of the warranty team for almost 10 years.