In this tutorial, I'll show you how to resitance test the Under-Drive Shift Solenoid, to see if it's BAD and thus lighting up the check engine light with a Diagnostic Trouble Code (DTC) P0765 or a Code 42 (if your Chrysler vehicle is OBD I equipped).
If you're wondering where the heck the Under-Drive Shift Solenoid (also know as Shift Solenoid D) is... this bad boy is inside the Transmission's Solenoid Pack.
OK, to make it as easy as possible to navigate this article, here are its contents at a quick glance:
- Symptoms Of A BAD Under-Drive Shift Solenoid (DTC P0765).
- What Tools Do I Need?
- Circuit Descriptions Of The Chrysler Transmission Solenoid Pack
- TEST 1: Under-Drive Shift Solenoid Resistance Test.
- Where To Buy The Chrysler Solenoid Pack.
- Low Reverse Shift Solenoid Test Conclusion.
- Chrysler Transmission Solenoid Pack Tutorials.
Symptoms Of A BAD Under-Drive Shift Solenoid (DTC P0755)
When the Under-Drive Shift Solenoid (also known as Shift Solenoid D), inside the Transmission Solenoid Pack, goes bad, you're gonna' see these specific symptoms:
- The check engine light (CEL) will be lit.
- One the following codes in memory:
- P0765: Under-Drive (UD) Solenoid Circuit Malfunction (OBD II equipped only).
- P0765: Shift Solenoid D Malfunction (OBD II equipped only).
- 42: Under-Drive Solenoid Circuit (OBD I equipped only).
- The Transmission will not shift gears:
- More specifically, it'll stay in 2nd gear no matter what speed you're driving the vehicle.
- This is called in tech terms: Limp In mode.
Testing the Under-Drive Shift Solenoid (Shift Solenoid D) is not hard, and in this tutorial I'll show you how to do it. If the Under-Drive Shift Solenoid is fried, you'll need to replace the entire Transmission Solenoid Pack.
What Tools Do I Need?
A Scan Tool is a handy (and a must have) tool to read Diagnostic Trouble Codes and view some of the Live Data parameters it provides.... but you don't need one to test the Under-Drive Shift Solenoid.
The most important tool that you're gonna' need is a multimeter. Your Multimeter can either be a digital multimeter or an analog multimeter.
Here are some of my suggestions:
- Don't have one or need to upgrade your Analog Multimeter to a Digital Multimeter, check out my recommendation here: Abe's Multimeter Recommendation.
- Scan Tool
- 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.
- 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).
- Basic Hand Tools
- These are: wratchet wrench, sockets, etc... that you'll need to disconnect the Solenoid Pack's electrical connector and remove and replace the Solenoid Pack if it's BAD.
Circuit Descriptions Of The Chrysler Transmission Solenoid Pack
Since the Under-Drive Shift Solenoid (Shift Solenoid D) is inside of the Transmission Solenoid Pack, we need to know which to pins to test. These pins are the ones that belong to the Solenoid Pack itself and not it's connector.
The Transmission Solenoid Pack has a total of 8 circuits (pins), and the 2 that we're interested in are pin #4 and pin #5
Pin #4 feeds power to the Under-Drive Shift Solenoid. Pin #5 feeds the activation signal. These are the two pins that we're gonna' test (with the Solenoid Pack's electrical connector disconnected).
|Chrysler Solenoid Pack Connector Pin outs|
|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.