A/T - 41TE/42LE DTC 41, 42, 43, or 44/Solenoid Circuit
Date: 1996Technical Bulletin # 347
^ Transmission:
41TE/42LE
^ Subject:
Solenoid circuit failures
^ Application:
Chrysler
41TE / 42LE
Solenoid Circuit Failures
^ DTC 41, L/R-L/U Solenoid Circuit Failure.
^ DTC 42, 2/4 Solenoid Circuit Failure.
^ DTC 43, O/D Solenoid Circuit Failure.
^ DTC 44, U/D Solenoid Circuit Failure.
Diagnostic trouble codes 41, 42, 43, and 44 are set when the shift solenoids fail an electrical continuity test. The TCM performs this test once every ten seconds by turning the shift solenoids off, completely. This results in the collapse of the magnetic field that surrounds an energized solenoid (figure 1). As this field collapses, it crosses the coils of the solenoid, generating a voltage pulse opposite in polarity from the normal operating current direction (figure 2). The TCM closely monitors the solenoid circuits for this reverse current spike during these tests. If there is no reverse voltage pulse, or if the pulse is not strong enough, the TCM enters one of the above DTCs for the solenoid that failed the test, then goes into failsafe, or limp mode.
Problems that can create this condition fall into four categories, listed below from the most frequent cause to the least frequent cause -
1. Insufficient battery voltage present at the TCM power terminals, solenoid body or excessive resistance in the TCM ground circuits.
2. Too much or too little resistance through the wiring or wire connections between the solenoid body and the TCM.
3. Too much or too little (short circuited) resistance through the solenoid circuits inside the solenoid body. Normal resistance is 1.0-2.0 ohms.
4. Failing transistors (excessive resistance) in the TCM used to operate the solenoid ground circuits.
Voltage Supply and Ground Circuits at the TCM and Solenoid Body.
Start at the battery, measuring battery voltage across the posts. The best time to do this is at the time the DTC is set if possible. Otherwise, measure voltage both before and after starting the engine. In order for the transaxle solenoids to perform properly, observed voltage must not drop below 12.4 volts. Do not assume that battery voltage is proper if the starter can aggressively crank over the engine. Although the starter requires far more current than the TCM, the starter is much more tolerant of slightly reduced voltage levels. The TCM is not typically starting to malfunction between 11.8 and 12.0 volts at the TCM terminals.
If battery voltage is within limits, the TCM terminal power and ground circuits should be checked, as well as the solenoid body power circuit. The negative probe of your DVOM should be connected to the battery negative post. With the key on, the same voltage observed at the battery should be observed at TCM pin 56 (figure 3). If voltage is below battery voltage, run a new fused circuit to pin 56 as-a test only. If the DTC no longer occurs, find the problem with the original power circuit. Also, if the unit has not gone into failsafe mode, the same voltage should be present at solenoid body pin four. If voltage is present but below battery voltage, replace the EATX relay, usually located on or near the TCM.
Next the TCM ground circuits need to be checked for dc voltage. On 1989 through 1992 vehicles, probe pins 57 and 58 with the engine running. On 1993 and 1994 vehicles, check pins 53 and 57 with the engine running. There should be no more than 0.1 volts dc present at these pins.
If there is over 0.1 volts, run an additional wire from the battery negative post to the ground pin showing the excessive voltage.
Solenoid Body to TCM Wiring.
Locate the circuit for the solenoid setting the DTC using the chart.
^ DTC 41, L/R-L/U solenoid, TCM pin 20 to solenoid body pin 7.
^ DTC 42, 2/4-L/R solenoid, TCM pin 190 to solenoid body pin 8.
^ DTC 43, O/D solenoid, TCM pin 60 to solenoid body pin 6.
^ DTC 44, U/D solenoid, TCM pin 59 to solenoid body pin 5.
Caution
Always verify that wire is the same color at the TCM and the solenoid body to assure correct wire location. Locate the female pin connection at both ends of the suspected circuit. Flatten one side of the pin connector so the pin will make a better contact (figure 4). If the DTC occurs again, cut the wire at both the TCM and the solenoid body and replace the wire with a new piece of 16 gauge wire.
Final Efforts...
At this point if everything is checking out okay but the DTC keeps recurring, it would be considered acceptable to replace the solenoid body, then the TCM, since all indications are that there is a problem inside one of these devices.