P0613: TCM Processor Fault
P0613 means the transmission control module (TCM), the computer that manages automatic transmission shifting, has detected a fault in its own processor or calculations. Seriousness ranges from a harmless false report with no symptoms to limp mode with a fixed gear and harsh shifts, so the car needs a scan soon.
You can drive, but get it checked soon
If the car shifts normally, short trips to a shop are usually reasonable. If it is in limp mode with a fixed gear and harsh shifts, drive only as far as needed, because the transmission is not shifting as designed and the cause is unconfirmed.
What it means
P0613 is stored when the transmission control module's internal self-check finds a processor or calculation problem. The scan tool shows which module stored it. On some vehicles the engine module reports the code on the transmission module's behalf. The only manufacturer document found is a Subaru bulletin for the 2022 BRZ 2.4 L automatic. It describes a check on a calculated gear ratio that set P0613 falsely in rare cases, and the fix was reprogramming the transmission module with improved self-diagnosis. That shows the code does not always mean failed hardware. Depending on the maker, the transmission may go into limp mode, which holds one gear and shifts harshly to protect itself. The code turns on the check engine light and is emissions relevant. It does not need a drive cycle to set.
Likely causes
- Transmission module software (self-diagnosis triggers falsely)Very likely
The one manufacturer bulletin found traced this code to a self-check that set it falsely, and reprogramming fixed it.
- Voltage dip, poor ground or supply at the transmission modulePossible
A module that gets unstable power or a weak ground can miscalculate and flag its own processor.
- Interrupted or faulty programmingPossible
If a software update or programming session was interrupted, the module's software can be incomplete or corrupt.
- Internal hardware defect (moisture, overheating)Less likely
Water or heat damage inside the module can cause a real processor failure, but this is the least common cause.
What you may notice
- Check engine light or transmission warning light
- Transmission limp mode (fixed gear, harsh shifts)
- Shifting that feels wrong or inconsistent
- Often no noticeable symptoms, because the report can be a sporadic false one
What to check, cheapest first
- 1Check that the battery is healthy and the terminals are clean and tight, since low voltage can upset control modules. · you can do it
- 2Read the stored codes with a scan tool and note which module stored P0613 and whether related codes such as P0606, P0614, P0631, P0700 or P0601 are also present. · you can do it
- 3Clear the code and see whether it returns. A one-time false report may not come back. · you can do it
- 4Inspect the power supply and ground connections to the transmission module for corrosion, looseness or damage. · mechanic
- 5Check for a software update or reprogramming for the transmission module, and look for any history of interrupted programming. · mechanic
- 6If power, ground and software check out and the code persists, inspect the module for moisture or heat damage and replace it if it is faulty. · mechanic
Related codes
Frequently asked questions
Can I drive with a P0613 code?+
Often yes for a short distance if the transmission shifts normally. If it is in limp mode or shifting harshly, limit driving and have it checked soon.
Can a loose gas cap cause P0613?+
No. P0613 is an internal fault in the transmission control module, not a fuel vapor leak.
Will P0613 pass an emissions test?+
Probably not while the check engine light is on. The code is emissions relevant, so it should be resolved and cleared first.
Can P0613 be fixed with a software update?+
Sometimes. A Subaru bulletin for the 2022 BRZ 2.4 L automatic fixed a false P0613 by reprogramming the transmission module. Whether an update exists for your car is something a shop can check.
Written with the help of AI from the public OBDex definition (CC0). Each make may use the code differently. Updated: 2026-11-10