Technical Description of OBD-II Trouble Code
Unable to Shift Out of Gear 6
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 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. Anecdotally, this code is more frequently observed in VW & Audi vehicles.
As we drive our vehicles, various modules and computers continuously monitor and adjust numerous components and systems to ensure smooth and efficient operation. One of these components is the automatic transmission (A/T).
The A/T alone contains numerous moving parts, systems, and components that work together to keep the transmission in the appropriate gear based on the driver’s demands. Another crucial part of this system is the TCM (Transmission Control Module), which monitors, adjusts, and correlates different values, speeds, and driver inputs to effectively shift the vehicle. Given the multitude of possibilities, it is best to start with the basics when troubleshooting this issue.
If you are searching for this code, it is likely that your vehicle is not accelerating quickly (if at all!). If you are stuck in a gear or neutral, it is advisable to avoid driving the vehicle until the problem is resolved. For example, if you are stuck in second gear while attempting to reach highway speeds, your engine will be under extreme strain to maintain the desired speed. This can lead to engine damage.
The ECM (Engine Control Module) will activate the CEL (Check Engine Light) and store a code P073B when it detects that the automatic transmission is stuck in gear 6.
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 repairs can lead to further damage. Ignoring the symptoms or neglecting the necessary repairs could result in costly repairs amounting to thousands of dollars. Automatic transmissions are complex systems that require proper maintenance for smooth operation.
What are some of the symptoms of the code?
Some symptoms of a P073B trouble code may include:
What are some of the common causes of the code?
Possible causes for this P073B code may include:
What are some P073B 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 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 the 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 leaking somewhere. Check your driveway for any signs of oil stains or puddles. This could be the source of the 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 described, among others. Corrosion on the housing or connectors is also indicative of a problem.
Basic Step #4
If everything checks out so far, use your OBD2 scanner to monitor the gear position and verify its functionality. Additionally, the drivability of the vehicle will provide clues as to whether the transmission is shifting properly. Is the acceleration slow even when the pedal is fully pressed? It may be stuck in a high gear (4, 5, 6, 7). Can you accelerate quickly, but the vehicle does not reach the desired speed? It may be stuck in a low gear (1, 2, 3).
