P072B: Stuck In Reverse

What Does The P072B Code Mean?

This is a generic powertrain diagnostic trouble code (DTC) and typically applies to OBD-II vehicles equipped with an automatic transmission. That may include but is not limited to vehicles from Volkswagen, Audi, Nissan, Mazda, Ford, etc. Although generic, the exact repair steps may vary depending on year, make, model and powertrain configuration. Accidentally, this code is more commonly seen on 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, you have the automatic transmission (A/T).

Within the A/T alone, there are countless moving parts, systems, components, etc. to keep the transmission in the correct gear according to driver’s demands. Another important part of the whole thing is the TCM (Transmission Control Module), it’s main function is to monitor, adjust and correlate different values, speeds, driver’s inputs, etc. and to effectively shift the vehicle for you! Given the sheer number of possibilities here, you will want to start, and most likely stick to, the basics here.

Most likely, if you are searching this code, your vehicle isn’t going anywhere fast (if anywhere at all!). If you are stuck in a gear or neutral, it would be a good idea to avoid driving the vehicle, or trying to, until the fault is repaired. Let’s say, you are stuck in second gear, trying to get up to highway speeds, you probably get it faster than 60km/h. That said, your engine will be working extremely hard to keep up the desired speed. Engine damage is highly likely in these events.

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

What Are The Symptoms Of The P072B Code?

Symptoms of a P072B trouble code may include:

• Abnormal vehicle speeds
• Low power
• Can only drive backwards
• Abnormal engine noises
• Reduced throttle response
• Limited vehicle speeds
• ATF (Automatic Transmission Fluid) leak (red fluid under vehicle)

What Are The Potential Causes Of The P072B Code?

Causes for this P072B code may include:

• Blockage in transmission hydraulics
• Low ATF level
• Dirty ATF
• Incorrect ATF
• Shift solenoid issue
• TCM issue
• Wiring issue (i.e. chafing, melting, short, open, etc.)
• Connector issue (i.e. melting, broken tabs, corroded pins, etc.)

How Serious Is This P072B Code?

Moderately-high I would say. These types of codes need to be attended to immediately. Sure, the vehicle may even drive down the street, but you will need to repair this before any further damage occurs. You could literally cost yourself multiple thousands of dollars by neglecting this too long or ignoring the symptoms. Automatic transmissions are extremely intricate designs and need to be maintained properly to keep up a smooth operation.

How Can You Fix The P072B Code?

Basic Step #1

Verify the integrity of your ATF (Automatic Transmission Fluid). Using the dipstick (if equipped), check the level of the A/T with the vehicle running and in park. This procedure varies a significant amount between manufacturers. That said, this information can usually be found quite easily with the service manual in the dash or sometimes even printed on the dipstick itself! Make sure the fluid is clean and free from debris.

If you do not remember ever doing a transmission service, it would be a good idea to check our records and service your transmission accordingly. You’d probably be surprised how dirty ATF can affect the functionality of your transmission.

Tip: Always check ATF level on flat surface to acquire accurate readings. Make sure to use manufacturer recommended fluid.

Basic Step #2

Any leaks? If your fluid happened to be low, it’s probably going somewhere. Check your driveway for any signs of oil stains or puddles. Who knows, this may be your issue. Either way, it’s a good idea to address this as well.

Basic Step #3

Check your TCM (Transmission Control Module) for any damage. If it is located on the transmission itself or any other location where it may be subject to the elements, take a look for any signs of water intrusion. This could most definitely cause an issue like this, among possible others. Any signs of corrosion on the housing or connectors is also a good sign of a problem.

Basic Step #4

If everything checks out up to now, depending on your OBD2 scanner’s capabilities, you could monitor the gear position and verify the functionality. That being said, it will be easy to tell if your transmission is shifting or not by its mere drivability. Do you have it floored and it accelerates painfully slow? It’s probably stuck in a high gear (4,5,6,7). Can you accelerated fast yet the vehicle’s speed never goes as fast as you’d like? It’s probably stuck in a low gear (1,2,3).

Recommended Parts

Below are some recommended auto parts to help you address the trouble code affecting your vehicle and get it running smoothly again:

>>> ACDelco GM OEM Dexron VI Automatic Transmission Fluid
>>> 4L60E Transmission Shift Solenoid Valve Set
>>> Twippo 372Pcs Waterproof Wire Connectors Kit
>>> TCM
>>> Autel Scanner MaxiCOM MK808S

Note: During the purchasing process, please check carefully whether the part you want to buy fits your car!

Reference Sources

P072B Stuck In Reverse, OBD-Codes.