Skip the auto shop - Our mechanics make house calls

P2789 OBD-II Trouble Code: Clutch Adaptive Learning at Limit

Check Engine Light

P2789 code definition

When the P2789 code applies to vehicles with dual clutch automated manual transmissions. When it is saved, it indicates that the powertrain control module (PCM) has detected an abnormality in the clutch’s adaptive learning system and that some error has occurred in the clutch system’s adaptive learning capabilities.

What the P2789 code means

To adapt to the vehicle owner’s style of driving, the dual clutch system, controlled by the vehicle’s computer, learns and adapts, thanks to input from a number of actuators and sensors. When the clutch adaptive learning system is unable to continue to learn and adapt, the P2789 code is saved, alerting the driver through an illuminated Check Engine Light or MIL (Malfunction Indicator Light), that the clutch adaptive learning system is not performing normally.

What causes the P2789 code?

The P2789 code is caused when the desired normal amount of adaptive response exceeds its predetermined limit. Depending upon the make and model of the vehicle, the P2789 code may not be stored until several failure cycles have occurred, but after this the code will be stored and the MIL or Check Engine Light will illuminate.

What are the symptoms of the P2789 code?

There may be no noticeable symptoms besides the illuminated MIL. This symptom, however, may also come alongside others, including:

  • Engine stall when the vehicle comes to a complete stop
  • Hard shifting
  • Clutch and/or transmission slippage
  • Lowered fuel efficiency
  • Transmission overheating
  • Failure of the clutch to engage or disengage

Other codes may also accompany the P2789 code, including DTC codes for:

  • Gear ratio slippage
  • Torque converter clutch
  • Transmission slippage
  • Clutch lock up

How does a mechanic diagnose the P2789 code?

To diagnose a P2789 code, a mechanic will use a code reader (or scanner) and a digital volt/ohmmeter. Upon scanning for Diagnostic Trouble Codes, other codes related to the clutch and transmission system should be diagnosed and fixed first, as one or more of these may be the cause of the P2789 code.

Mechanical clutch failure is a common cause of the P2789 code. So, after checking for other codes, the mechanic will diagnose and repair any defective solenoids, sensors, and/or actuators. The mechanic will also take steps to check for insufficient fluid pressure, as well as transmission diagnostics.

Common mistakes when diagnosing the P2789 code

The most common mistakes when diagnosing the P2789 code generally involve overlooking malfunctions in the shift solenoid, pressure control solenoid, and/or wiring. When these are missed, a clutch or transmission replacement or rebuild is often done when it is not called for, costing the vehicle owner more while failing to solve the problem.

How serious is the P2789 code?

While some instances of the P2789 code come with no symptoms at all, this is a serious problem that can get worse if left undiagnosed. Hard shifts, a clutch that will not disengage or engage, and/or an engine that stalls at idle can put the driver in significant danger, depending on where and when these malfunctions happen.

What repairs can fix the P2789 code?

Some common repairs for the P2789 code include:

A test must be done after each repair to determine whether or not the mechanic has found the cause of the P2789 code.

Additional comments for consideration regarding the P2789 code

Failure to continue to learn and adapt to your driving style may not seem like a major problem, but considering how many other issues can be triggered by the P2789 code and codes associated with it, it is definitely not one to leave alone. An undiagnosed P2789 code problem could put you in serious danger and could cause other problems for your transmission and clutch. If you’ve experienced one or more of the symptoms of this code and your MIL or Check Engine light has illuminated, you should get it diagnosed and repaired immediately.

Need help with a P2789 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Post a question and get free advice from our certified mechanics.

ASK A QUESTION

More related articles

How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...
How to Transfer a Car Title in Idaho
In order to prove ownership of a car, you must have the title. However, when a car is sold, given away or inherited, the title needs...
The Traveler’s Guide to Driving in Malaysia
CraigBurrows / Shutterstock.com Malaysia is a popular destination for many tourists today. The country has amazing sights and attractions that you will want to explore....


Related questions

Q: Engine problems.

Hello. From what you describe it would appear likely that the backfiring and performance issues are a result of the fuel problem. A rich fuel mixture can be caused by a wide variety of issues. A few things I would...

Q: i have a check engine light on

Hello there, thank you for asking about your 2004 Toyota Camry. Code P0012 relates to the camshaft position sensor which monitors the speed of the camshaft and relays this information to your car's computer, which helps to control ignition timing...

Q: Why is my car sputtering? 2005 Saturn Ion

Hi there - a car that sputters may have an ignition misfire, or a fuel supply issue causing this behavior. You mentioned the Check Engine Light is on - getting the problem codes is task #1. The problem codes will...