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Signs of a Bad Transmission Control Module & TCM Replacement Cost

Signs of a Bad Transmission Control Module

TCMs and Replacement Cost

Any signs of a bad transmission control module warrant a trip to your local mechanic. Your vehicle’s transmission control module (TCM) is like a tiny computer. It has the important job of interpreting electrical sensor output of components in an engine with an automatic transmission

The TCM processor helps understand various signals transmitted by the drivetrain’s engine control module (ECM), and outputs signals to control a vehicle’s speed, shifting, and regulate the temperature of a transmission. The input speed sensor sends critical rotational speed measurements to the TCM to determine the actual rotational speed of the torque converter

The wheel speed sensor also works together with the TCM. Unlike having to manually engage the clutch with your left foot in a vehicle with a manual transmission, the wheel speed sensor tells the TCM when to decouple the transmission (aka engage the clutch).  The wheel speed sensors also tell the module the speed of the car, whether the vehicle is going up or downhill so that it can adjust gear and tire rotation accordingly. If any of these sensors go bad, the results can spell disaster for your vehicle’s performance at best, and extremely dangerous at worst.

What are the Symptoms of a Bad Transmission Control Module?

Symptoms of a bad transmission control module include but are not limited to:

  • Inability to shift or stuck in gear
  • Significantly lower gas mileage
  • Difficulty downshifting when your vehicle decelerates
  • Difficulty upshifting while accelerating
  • Gears shifting unexpectedly
  • Gears slipping
  • Transmission overheating
  • Check engine light on throwing p codes P0612, P0613, P0700, or P0706

Experiencing any of the warning signs of a bad TCM?

If you are unable to accelerate as fast as you should, or your gears are slipping, your car is unsafe to drive (even if it’s still semi-operable). 

Is Your Car or Truck in Limp Mode?

When only one or two gears of a vehicle are working, it is said to be in “limp mode”. Limp mode is the vehicle’s safety default mode, and the automobile needs to have the TCM replaced for it to be driven again safely. If you’re experiencing any signs of a bad transmission control module, contact your local transmission place to get the problem diagnosed and fixed. 

TCM Replacement Cost

The cost of TCM replacement depends on the make and model of your vehicle, plus the cost of parts and labor. It’s also important to factor in the amount of time it could take to replace the module because some imported parts can take 2 to 4 weeks to arrive. 

TCM Swap & Labor

While swapping out a box might seem simple, the TCM is located inside the transmission in many modern cars, trucks, and SUVs. Opening the transmission is a laborious task, which is why it is reasonable to expect labor costs of at least $300 to replace the transmission control module. 

In many older models (especially automatic transmissions)  the module is located in an area of the engine that is much easier to reach. Replacing it in some of these older models simply means pulling a part out and plugging in the new or refurbished one. Unfortunately, it is not always that straightforward. 

A licensed mechanic should do a thorough diagnostic and inspection of your vehicle to properly pinpoint the issue, don’t just rely on the diagnostic code reader. Often times, when the TCM is malfunctioning, it registers confusing codes that may not be accurate. 

TCM Part Cost

The cost of the control module itself varies and as you might expect, replacing import TCMs is usually more expensive. These prices were found using an online search to serve as examples, and do not reflect the exact amount it will cost to replace or repair your control module. 

Transmission Control Module Cost by Make and Model
GMCSierra Denali2015$260
BMW 320i2001$50
Jeep Cherokee1996$100

Schedule Transmission Control Module Replacement

Call My Transmission Experts today to schedule an appointment at your local shop if you think you have a bad TCM. We offer a wide range of financing options and offer free emergency towing to our shop if you are stuck in the greater Houston areas including Katy, Montgomery, Kingwood, West Houston in Bear Creek, and Northwest Houston on Jones Rd near 290.