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Engine-Codes – Generic – P0766

P0766 Code - Shift Solenoid 'D' Performance or Stuck Off

Quick Answer

The OBD-II trouble code P0766 indicates that the transmission shift solenoid 'D' is either not performing as expected or is stuck in the off position. Common causes include Faulty shift solenoid 'D', Electrical issues such as corroded wiring or connectors, Low transmission fluid levels or dirty fluid. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0766 indicates Shift Solenoid 'D' Performance or Stuck Off.
Common causes
Common causes include Faulty shift solenoid 'D', Electrical issues such as corroded wiring or connectors, Low transmission fluid levels or dirty fluid.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Sep 10, 2024
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Code P0766 Description

The OBD-II trouble code P0766 indicates that the transmission shift solenoid 'D' is either not performing as expected or is stuck in the off position. This solenoid is responsible for regulating the flow of transmission fluid to engage or disengage specific gears within the transmission. When this solenoid malfunctions, it can lead to various issues with the vehicle's shifting patterns, affecting its overall performance and drivability.

OBDII Code P0766 - Shift Solenoid 'D' Performance or Stuck Off
P0766 Code - Shift Solenoid 'D' Performance or Stuck Off

Common Causes of P0766

  1. Faulty shift solenoid 'D'
  2. Electrical issues such as corroded wiring or connectors
  3. Low transmission fluid levels or dirty fluid
  4. Malfunctioning transmission control module (TCM)
  5. Mechanical blockages within the transmission

Symptoms of P0766

  1. Harsh shifting between gears
  2. Delayed or erratic gear changes
  3. Transmission slipping
  4. Decreased fuel efficiency
  5. Illumination of the Check Engine Light

How to Fix P0766

  1. Diagnose the issue by using a scan tool to retrieve the specific trouble code and further inspecting the transmission system.
  2. Check the transmission fluid level and condition, topping off or replacing it if necessary.
  3. Test the shift solenoid 'D' for proper operation and replace it if found to be faulty.
  4. Inspect the electrical connections and wiring related to the shift solenoid for any damage or corrosion, repairing or replacing as needed.
  5. If the issue persists, consider having the TCM or other transmission components inspected by a professional mechanic.

Cost to Fix P0766

The typical repair costs for addressing the P0766 code can range from $200 to $500, including parts and labor. However, it's important to note that the specific diagnosis time and labor rates at auto repair shops can vary significantly based on various factors. Rates in metropolitan areas or at dealerships may be higher, while independent shops often charge less. It's advisable to obtain quotes from multiple sources to get a more accurate estimate for the repair.

What does this mean?

Tech Notes for P0766

When the a transmission solenoid is stuck off, in most cases the problem is not the electrical part of the solenoid; the problem is foreign material obstructing the mechanical function of the solenoid or the flow of the fluid through the transmission valve body. If the transmission fluid is very dirty, it is recommend changing the transmission fluid and if possible removing the transmission pan for further diagnosis. Excessive debris or metal particles on the transmission pan could be an indication that there is a transmission mechanical failure and that the transmission will need to be rebuilt or replaced.

When is the Code Detected?

The P0766 code is detected when the ECM has detected a mechanical fault with the solenoid energized, valve stuck off

Need more information about the P0766 code?

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Code P0766 Information for Specific Makes

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0766 Code

No Frequently Asked Questions about P0766 Code found.

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  • Replaced a and b selonoids on2007 mercury Milan still didn't help code po757 b stuck on plus d performance stuck off where to next change all selonoids are try a new tranny

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  • More than likely you have to rebuild the solenoids. How was the transmission fluid condition? did smell burnt?

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