P0766 Shift Solenoid C Stuck On

P0766 Shift Solenoid C Stuck On: Causes, Symptoms, and Solutions

Have you ever experienced a car that feels like it can’t shift gears? It can be frustrating, especially when you’re in a hurry.

One possible reason for this is a problem with your shift solenoid. In particular, if you’ve been diagnosed with a P0766 Shift Solenoid C Stuck On code, you may be wondering what this means and what you can do about it. In this article, we’ll dive deep into this issue, exploring its causes, symptoms, and solutions.

What is a Shift Solenoid?

Before diving into the specifics of the P0766 code, let’s first talk about what a shift solenoid is. Essentially, a shift solenoid is an electro-hydraulic valve that controls the flow of transmission fluid in your car. It’s responsible for directing the fluid to the appropriate gear whenever you shift, ensuring that the gears engage smoothly and reliably. Without properly functioning shift solenoids, your car may not be able to shift gears at all.

What is the P0766 Code?

The P0766 code is a diagnostic trouble code (DTC) that indicates a problem with the Shift Solenoid C. Specifically, it means that the solenoid is stuck in the “on” position, which can prevent your car from shifting gears properly. This code is typically triggered by a fault in the solenoid circuit, either due to a wiring issue or a malfunctioning solenoid.

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Causes of P0766 Shift Solenoid C Stuck On

There are several potential causes of a P0766 code, including:

  1. Malfunctioning Solenoid: The most common cause of a P0766 code is a faulty shift solenoid. If the solenoid is stuck in the “on” position, it can prevent the transmission from shifting into the appropriate gear.
  2. Wiring Issues: Another possible cause of a P0766 code is a problem with the wiring that connects the solenoid to the transmission control module (TCM). Corrosion, damage, or loose connections can all cause a solenoid circuit malfunction.
  3. TCM Malfunction: In some cases, the issue may be with the TCM itself. A malfunctioning TCM can send incorrect signals to the solenoid, causing it to get stuck in the “on” position.

Symptoms of P0766 Shift Solenoid C Stuck On

If you have a P0766 code, you’re likely to experience several symptoms that indicate a problem with your shift solenoid. These may include:

  1. Delayed Shifting: One of the most common signs of a solenoid issue is a delay in shifting. You may notice that your car takes longer than usual to shift gears, or that it seems to struggle to engage at all.
  2. Stuck in One Gear: Another possible symptom of a P0766 code is being stuck in one gear. You may find that your car can only shift into one gear, or that it seems to be stuck in a particular gear even when you’re not pressing the accelerator.
  3. Overheating Transmission: If your car is struggling to shift gears, it may put additional strain on your transmission. Over time, this can cause your transmission to overheat, which can lead to serious damage.

Solutions for P0766 Shift Solenoid C Stuck On

If you’re experiencing a P0766 code, there are several potential solutions you can explore. These may include:

  1. Solenoid Replacement: If the problem is indeed a faulty solenoid, the best solution may be to replace it. A qualified mechanic can remove the old solenoid and install a new one, ensuring that your transmission shifts smoothly once again.
  2. Wiring Repair: If the issue is with the wiring, your mechanic may be able to repair the circuit or replace any damaged wires. This should restore proper communication between the solenoid and the TCM.
  3. TCM Replacement: In rare cases, the TCM may be at fault. If this is the case, your mechanic may recommend replacing the entire module to ensure proper communication with the solenoid.


A P0766 Shift Solenoid C Stuck On code can be a frustrating issue that prevents your car from shifting gears properly. However, by understanding the causes, symptoms, and potential solutions, you can take steps to address the issue and get back on the road safely. If you’re experiencing any of the symptoms described in this article, we recommend consulting with a qualified mechanic to diagnose and repair the issue promptly.


  1. Can a P0766 code cause damage to my transmission?

Yes, if left untreated, a P0766 code can put additional strain on your transmission and cause it to overheat, potentially leading to serious damage.

  1. How much does it cost to replace a shift solenoid?

The cost of replacing a shift solenoid can vary depending on the make and model of your car. Generally, you can expect to pay anywhere from $150 to $400 for parts and labor.

  1. Can I drive my car with a P0766 code?

While it may be possible to drive your car with a P0766 code, we don’t recommend it. Continuing to drive with a malfunctioning transmission can put you and your passengers at risk.

  1. What causes a shift solenoid to fail?

A shift solenoid can fail due to several factors, including age, wear and tear, and improper maintenance.

  1. How can I prevent future shift solenoid issues?

Regular maintenance and check-ups can help prevent future solenoid issues. Make sure to keep up with your car’s recommended maintenance schedule and have any issues addressed promptly.