John Deere Fault Codes List & What They Mean

When you’re experiencing a problem with your John Deere, fault codes can be beneficial. These codes make it easy to pinpoint the exact cause of the problem you’re experiencing. Additionally, they can help you detect problems within your machine early before they become bigger issues. 

John Deere fault codes are error codes produced by the various control units on the machine. When something malfunctions within one of the machine’s systems, the corresponding control unit will have a code that tells precisely what the error is. This could be an issue with the essential fluids, bad wiring, or transmission/engine errors.  

John Deere Fault Codes List And What They Mean

Fault codes are very helpful in determining what is going on with your John Deere when you run into a problem with the tractor. However, the number of different codes that are listed in your manual can be overwhelming and hard to understand. 

To make this simpler, we’ve researched these codes and what they mean and compiled this information. You will find the codes sectioned by the controller unit they come from, what the code means and information to help you understand the systems affected. 

1 John Deere Engine Codes (ECU) List

The Engine Control Unit gives the John Deere ECU fault codes. The ECU is responsible for controlling many important things. When one of the components controlled by the ECU doesn’t function properly, it will generally be noticeable in the engine’s performance. 

When your machine gives an ECU code, it’s almost always related to the engine, or another component that interacts with the engine directly, such as the fuel and oil. 

ECU codes should be taken seriously until the issue is ruled out. Issues that throw ECU codes can cause severe damage to your John Deere machine. For example, if some of these problems are not addressed, they can eventually lead to engine failure. 

You can see some common ECU codes and what they mean in the list below:

  • ECU 000097.03: Water has been detected in the fuel (can damage the engine)
  • ECU 000097.04: The water trap needs to be emptied (water can damage the engine)
  • ECU 000100.01: Low oil pressure (check oil levels)
  • ECU 000100.03: Bad voltage signal of oil pressure 
  • ECU 000100.31: Oil pressure was detected while the engine was off
  • ECU 000102.02: Manifold air pressure sensor error
  • ECU 000102.03: Intake manifold pressure sensor error
  • ECU 000102.04: Manifold air pressure voltage signal error
  • ECU 000103.00: More speed with limited engine power
  • ECU 000103.08: Invalid turbocharger speed
  • ECU 000103.31: No turbocharger speed detected.
  • ECU 000105.04: Temperature signal error
  • ECU 000105.15: Foreign particles in the cooling system
  • ECU 000105.16: Extremely elevated air temperature in the manifold
  • ECU 000108.02: Barometric pressure sensor error
  • ECU 000110.00: High engine coolant temperature (coolant needs to be cooler)
  • ECU 000157.10: Decreased fuel line pressure
  • ECU 000174.16: Elevated fuel temperature 
  • ECU 000611.04: Electronic injection wiring damaged

2 John Deere ACU Fault Codes List

ACU fault codes are given by the Armrest Controller Unit. These codes are generally given to alert you of errors within certain systems of your machine. In this group, you’ll find codes related to electrical systems that are important to your transmission and other critical components of your John Deere.

Most relate to communication errors between certain command switches and the system they interact with. Many of them involve essential components of the tractor not functioning properly. Some can interfere with essential functions and prevent you from carrying out your everyday tasks.

The errors within this system are generally a result of damaged or old wiring. These codes are often accompanied by many common electrical symptoms. When this controller detects an error, it’s best to address the problem immediately. 

Here is a list of ACU codes for John Deere and what they mean:

  • ACU 000158.04: Low ACU voltage
  • ACU 000177.17: Low oil temperature (can affect engine speed)
  • ACU 000581.07: Transmission not responding
  • ACU 002000.09: No ECU message or fuse F24
  • ACU 002003.09:  No PTP/PTI message 
  • ACU 002020.09: Missing SFA message
  • ACU 002049.09: Missing CAB message
  • ACU 523775.02: Hand presence switch error
  • ACU 523805.03: Specific lever control error
  • ACU 523955.31: High engine load in manual mode
  • ACU 523961.02: Gears switching to park while in gear
  • ACU 523961.07: Park lock engagement error (not locking into park)
  • ACU 523962.31: Invalid MFWD speed

Some ACU fault codes can indicate complex issues within the electrical systems of the machine. Some of them can be near impossible to figure out on your own without the special tools and training required. So if you run into any electrical problems, it’s best to find a John Deere specialist who can diagnose and fix the reason for the fault code. 

3 John Deere TCU Fault Codes List

The TCU (Transmission Control Unit) is a system that controls modern automatic transmissions. Your tractor display might show some error codes with ‘TCU’ that need an immediate fix. Here are some of the fault codes.

TCU fault codes reflect issues with the automatic transmission. They come from the Transmission Control Unit, which is responsible for monitoring important components within the transmission. 

It also helps ensure many essential functions within the transmission are carried out correctly. These functions include the way the transmissions shifts. When something goes wrong with the TCU, it can cause many shifting problems, including rough shifting, slipping, and even improper gear selection. 

It also communicates with the vehicle speed sensor and throttle position sensor. The TCU gathers information from these sensors and communicates with ECU to help the machine convert to the best shifting pattern during certain situations. Errors in this communication can also cause various shifting issues. 

Another important role of the TCU is that it communicates with the traction control system to change shifting patterns when abnormal traction conditions are detected. This can impact the traction control when it malfunctions. 

The list below provides some of the Johne Deere TCU fault codes and what they mean:

  • TCU 304020.02: Transmission enables signal error 
  • TCU 304019.05: Clutch petal sensor not working
  • TCU 304050.04: (Hydrostatic Speed Sender) – Channel 1 ground circuit.
  • TCU 304024.04: Electrical short to ground (transmission temperature sensor)
  • TCU 304032.03: Shorted circuit in the clutch pedal switch 
  • TCU 304033.03: The transmission enable sensor has a short circuit
  • TCU 304040.03:  Open or shorted circuit in the transmission oil temperature sender

If you get a fault code that is related to the transmission, you should have a John Deere specialist inspect the problem as soon as possible. Letting minor transmission errors wait could lead to severe damage to the transmission. 

Some faults could eventually cause transmission failure, which is rather costly to replace. The exact cost will vary depending on the model of your John Deere. 

4 John Deere BCU Fault Codes List

BCU fault codes are produced by the Basic Control Unit. This is the main control unit on your John Deere. This means that it plays a role in almost all functions of the tractor. 

Fault codes that are given by the BCU often relate to faulty wiring/short circuits within essential sensors and other systems. They will also let you know when the voltage doesn’t properly align with the RPMs. 

Furthermore, BCU fault codes can sometimes mean that an essential component of the machine, such as the hand brake, is not functioning as it should. 

The list below lists some BCU fault codes and what they mean:

  • BCU 000070.31: Handbrake error
  • BCU 000084.02: Faulty circuit in wheel speed sensor 
  • BCU 000168.16: Voltage too high while the engine is running
  • BCU 000168.17: Voltage too low at 1500 RPM. 
  • BCU 000168.18: Voltage to low while above 1500 RPM
  • BCU 000186.02: Faulty electrical circuit in the rear PTO speed sensor. 
  • BCU 000190.02: Faulty circuit in the engine speed sensor
  • BCU 000629.12: Internal error within the control unit
  • BCU 000639.12: System error within the control unit 
  • BCU 000746.31: Faulty circuit in the differential lock solenoid valve.
  • BCU 000980.07: Rear PTO switch error 
  • BCU 001676.31: Faulty circuit in the LTC coolant pump relay 
  • BCU 001882.02: Faulty circuit in the front PTO speed sender 
  • BCU 299780.07: Turn switch signal error 
  • BCU 302001.31: 250 hours of service
  • BCU 302002.31: 500 hours of service
  • BCU 302003.31: 750 hours of service
  • BCU 302004.31: 1,500 hours of service

Like transmission errors, electrical issues are not likely a repair you’ll be able to handle on your own. If you run into one of these errors, you reach out to a professional who has the proper training and tools to find and fix the exact issue. 

5 Retrieving Engine Fault Codes

Understanding the different fault codes is not helpful unless you know how to retrieve the codes. 

The steps below explain how you can retrieve the engine fault codes for your John Deere:

  1. Park your John Deere on level ground. 
  2. Make sure that your broom is fully lowered and retracted. 
  3. Put your tractor in neutral and engage the parking brake. 
  4. Make sure the ignition switch is on. However, the engine should not be running.  
  5. Locate the reset button on the dash and hold it down for about 5 seconds or until the fault lamp flashes a code number. 
  6. The first number that flashes will let you know if there are any active codes. If this number is 32, it means that there are active codes. If it is 88, it means that there are not any active codes. (Active codes let you know that there is currently an issue with the machine and may or may not be stored permanently.) 
  7. The second number that flashes will let you know if there are any stored codes. If the number is 33, it means that there are stored fault codes. If it is 88, it means that there are no stored codes. (Stored codes cannot be cleared and will remain stored until the issue is resolved.)
  8. Once you’ve done this, make sure you turn your ignition back off to avoid draining the battery. 

It’s important to note that your tractor may derate if the engine operation sensor input goes above the average operating range. Anytime this happens, you will receive a fault code. 

How Do You Check the Codes on a John Deere?

John Deere does not operate on the OBD system for fault codes. Because of this, you cannot check them using a regular OBD meter. 

Some newer models are compatible with the TractorPlus app that is available from Google Play and the App Store. This app allows you to see the diagnostic codes along with much more information that is helpful when operating your tractor. 

The other option is to put the tractor in Diagnostics Mode. The steps below will help you do this:

  1. In your fuse box, you should have a spare fuse. Move this fuse to the Diagnostics Mode.
  2. Once you’ve installed the fuse, the tractor will be in diagnostic mode. 
  3. Change the setting on the screen to “All.” This will scan all of the controllers for error codes. 
  4. If any codes are found, they will be displayed. The first three letters of the code will let you know which controller sent the code. The number following these letters will let you know what the exact issue with that controller is. 
  5. It’s best to write the code down to make it easier to research the meaning. You may find your code listed in the article above. However, it’s always best to consult your manual if possible to ensure you receive accurate information for your specific John Deere model. 


Fault codes make getting to the bottom of issues with your John Deere machine a much simpler task. Additionally, they help you detect minor issues quickly so you can have them repaired before they turn into a bigger and more complex problems. 

You may not always see symptoms of the errors. However, you should have a John Deere specialist take a look at the machine if you receive an error code. Thanks to the many quality sensors, issues may be detected before you notice signs of the problem. Running the machine with a minor underlying issue could result in further damage. 

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