P072B Stuck In Reverse

Technical Description of OBD-II Trouble Code

Unable to Shift Out of Reverse

What does that signify?

This is a standard diagnostic trouble code (DTC) for powertrain issues and is commonly found in OBD-II vehicles with automatic transmissions. This can include vehicles from various manufacturers such as Volkswagen, Audi, Nissan, Mazda, Ford, and others. While it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle. Anecdotally, this code is more frequently observed in VW & Audi vehicles.

As we drive our vehicles, numerous modules and computers monitor and adjust a vast amount of components and systems in order to make the vehicle’s operation seamless and efficient. Among those components and systems is the automatic transmission (A/T).

Within the A/T alone, there are numerous moving parts, systems, and components that work together to keep the transmission in the correct gear based on the driver’s demands. Another crucial part of this system is the TCM (Transmission Control Module), which monitors, adjusts, and correlates various values, speeds, and driver inputs to effectively shift the vehicle. Given the complexity of this system, it is best to start with the basics when troubleshooting.

If you are searching for this code, it is likely that your vehicle is not moving forward (or at all!). If you are stuck in a gear or neutral, it is advisable to avoid driving the vehicle until the issue is resolved. For example, if you are stuck in second gear and trying to reach highway speeds, your engine will be working extremely hard to maintain the desired speed. This can potentially cause engine damage.

The ECM (Engine Control Module) will activate the CEL (Check Engine Light) and store a code P072B when it detects that the automatic transmission is stuck in reverse.

Automatic transmission gear indicator:

What is the severity of this DTC?

I would classify it as moderately high. Codes like this should be addressed immediately. While the vehicle may still be drivable, delaying the repair could lead to further damage. Neglecting this issue or ignoring the symptoms could potentially cost thousands of dollars. Automatic transmissions are intricate systems that require proper maintenance for smooth operation.

What are some of the symptoms of the code?

Symptoms of a P072B trouble code may include:

What are some of the common causes of the code?

Possible causes for this P072B code may include:

What are some P072B troubleshooting steps?

Basic Step #1

Check the integrity of your ATF (Automatic Transmission Fluid). Use the dipstick (if available) to check the A/T level while the vehicle is running and in park. The procedure for this may vary depending on the manufacturer, but the information can usually be found in the service manual or on the dipstick itself. Ensure that the fluid is clean and free from debris. If you have never serviced the transmission, it would be wise to check your records and service the transmission accordingly. Dirty ATF can significantly affect the functionality of your transmission.

Tip: Always check ATF level on a flat surface for accurate readings. Use the manufacturer-recommended fluid.

Basic Step #2

Are there any leaks? If your fluid level is low, it is likely that there is a leak somewhere. Check your driveway for any signs of oil stains or puddles. This could potentially be the cause of your issue. Regardless, it is important to address any leaks.

Basic Step #3

Inspect your TCM (Transmission Control Module) for any damage. If it is located on the transmission or in a location exposed to the elements, look for signs of water intrusion. This can cause issues like the one you are experiencing. Corrosion on the housing or connectors is also indicative of a problem.

Basic Step #4

If everything checks out so far, depending on the capabilities of your OBD2 scanner, you can monitor the gear position and verify its functionality. However, it is usually easy to tell if your transmission is shifting or not based on how the vehicle drives. If you have the accelerator floored and the acceleration is slow, it is likely stuck in a high gear (4, 5, 6, 7). If you can accelerate quickly but the vehicle’s speed does not increase as desired, it is likely stuck in a low gear (1, 2, 3).

Professional Service

While we always recommend seeking mechanical solutions for this issue, if that is not possible, we offer the option to permanently delete this specific DTC. All other codes will still be addressed. If you are interested in this option, please upload your ECU file to our portal.