Testing Diagnostic Trouble Code P0750 (Low Reverse Shift Solenoid Malfunction)

If your scan tool is recording a P0750: Low Reverse Solenoid Circuit Malfunction (if your Chrysler vehicle is OBD II equipped) or a trouble code 41: Low Reverse Solenoid Circuit , and your Chrysler (Dodge or Plymouth) transmission is not shifting out of 2nd gear... then you've come to the right place to test the Low Reverse Shift Solenoid.

Here are the contents of this test tutorial, at a quick glance:

  1. Symptoms Of A Bad Low Reverse Shift Solenoid (DTC P0750).
  2. What Tools Do I Need?
  3. Circuit Descriptions Of The Chrysler Transmission Solenoid Pack.
  4. TEST 1: Low Reverse Shift Solenoid Resistance Test.
  5. Where To Buy The Chrysler Solenoid Pack.
  6. Chrysler Transmission Solenoid Pack Tutorials.

En Español You can find this tutorial in Spanish here: Cómo Probar Código P0750 (Solenoide de Cambio A) (at: autotecnico-online.com).

Symptoms Of A Bad Low Reverse Shift Solenoid (DTC P0750)

When the Low Reverse Shift Solenoid (also known as Shift Solenoid A), inside the transmission Solenoid Pack, goes bad, you're gonna' see two specific symptoms, these are:

  1. The check engine light (CEL) will be shining nice and bright on your instrument cluster.
    1. If OBD II equipped, You'll have P0750: Low Reverse Solenoid Circuit Malfunction stored in the TCMs memory.
    2. Depending on the type of scan tool you own, this code can be translated as: P0750: Shift Solenoid A Malfunction (OBD II equipped only).
    3. If OBD I equipped, you'll see trouble code 41: Low Reverse Solenoid Circuit.
  2. The transmission will not shift gears:
    1. More specifically, it'll stay in 2nd gear no matter what speed you're driving the vehicle.
    2. This is called in tech terms: Limp In mode.

It stinks that you're having this issue (P0750 or Code 41), but the cool thing is that it's not that hard to test this yourself and replace the Solenoid Pack if indeed the Low Reverse Shift Solenoid is BAD.

What Tools Do I Need?

The most important tool that you're gonna' need is a multimeter. Your multimeter can either be a digital multimeter or an analog multimeter.

A scan tool really isn't needed to actually test the Low Reverse Shift Solenoid... but it does come in handy when it comes to checking for diagnostic trouble codes (especially if your Chrysler vehicle is OBD II equipped and you're not able to manually extract the trouble codes).

Here are some of my suggestions:

  1. Multimeter
    1. Don't have one or need to upgrade your analog multimeter to a digital multimeter, check out my recommendation here: Abe's Multimeter Recommendation.
  2. Scan Tool
    1. As I mentioned above, you don't need to use a scan tool to take advantage of the test info in this tutorial, but it does come in handy to read any trouble codes.
    2. If you don't own a scan tool yet, I recommend taking a look at these 2 articles I've written: Scan Tool Essentials You Should Know! (at: troubleshootmyvehicle.com) and Actron CP9580 Scan Tool Review (also at: troubleshootmyvehicle.com).

Circuit Descriptions Of The Chrysler Transmission Solenoid Pack

Circuit Descriptions Of The Chrysler Transmission Solenoid Pack -Testing Diagnostic Trouble Code P0750

Now, just in case you're not aware... the Low Reverse Shift Solenoid (Shift Solenoid A) is part of the transmission coil pack (this also means that if your tests indicate it's BAD, you'll need to buy the whole solenoid pack to solve the problem).

The transmission coil pack is bolted to the transmission (see the photo at the top of this page). A connector with 8 wires connects to the solenoid pack.

2 of those 8 wires are the ones that feed Power and the activation signal to the Low Reverse Shift Solenoid and in this section, I'll identify them for you. This is info you'll need to know to test the solenoid.

Chrysler Solenoid Pack Connector Pin outs
Pin Wire Color Description
1 Yellow w/ Black stripe* 2-4 Pressure Switch
2 Dark Green* Low/Reverse Pressure Switch
3 Orange w/ Black stripe* Overdrive Pressure Switch
4 Red* Power (10 to 12 Volts DC)
5 Pink* Underdrive (UD) Solenoid
6 Brown* Overdrive (OD) Solenoid
7 Light Blue* Low/Reverse Solenoid
8 White* 2-4 Shift Solenoid

  * Your specific Chrysler, Dodge, Plymouth vehicle may have different colors.

One last thing before we move on to the next page (and start testing)... the solenoid pack will have the above 8 numbers embossed on it. This will further aid you in identifying the metal male terminals you'll need to test in the next page.