This section covers the electronically-controlled transmissions and transaxles built domestically by Chrysler. Unfortunately, unlike GM and Ford, there are only a few units you can check thoroughly without using a scan tool.

The 42RH and 46RH receive their control signals from the main computer, so transmission-related diagnostic trouble codes appear along with engine trouble codes. The procedures we’ve looked at so far will work for checking these units, too.

But Chrysler’s 41TE and 41LE have their own transmission computer; these units won’t provide diagnostic trouble codes through the malfunction indicator lamp. To check these systems, you’ll have to use a scan tool. That’s the bad news.

The good news is that, using a scan tool equipped with the proper cartridge or software, diagnosing these Chrysler transaxles is relatively easy. The scan tool provides far more than just diagnostic trouble codes: It even helps the computer relearn shift timing information and clutch fill capacities.

So the real key to diagnosing most Chrysler transmissions is having a good scan tool available. With it, you should be able to diagnose these units quickly and accurately.

Of course, that still leaves us with the 42RH and 46RH units. While a scan tool would be helpful for diagnosing these units, you can check the diagnostic trouble codes and computer signals without it. And you can force the unit to shift electrically, the same as with GM and Ford units. And even though the computer won’t display transmission-specific codes for 41TE and 41LE units, it will display engine codes; a problem with the throttle position sensor or MAP sensor can still have an effect on transmission operation.

And let’s not forget Jeep: As with the 41TE and 41LE units, Jeeps require a scan tool for displaying trouble codes. But you can still check the signals to the transmission, and force the transmission to shift using these procedures.

We’ll start by looking at the procedure for retrieving and clearing diagnostic trouble codes on Chryslers, and then move on to the transmission-specific information. This information includes:

Remember to follow these procedures all the way through to the end, using the diagnostic flowchart on page 8 as your guide. This procedure will help you make sure that your diagnosis is accurate and complete.

Now you’re ready to move on to the first part of this section, covering retrieving and clearing diagnostic trouble codes.

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