The P0773 diagnostic trouble code (DTC) indicates a problem with the electrical circuit of shift solenoid “E” within your vehicle’s automatic transmission. This article explains the code, its symptoms, common causes, and troubleshooting steps.
What Does the P0773 Code Mean?
Automatic transmissions use shift solenoids to control fluid flow and engage different gears. The Powertrain Control Module (PCM) monitors these solenoids. When the PCM detects an electrical malfunction in the circuit of shift solenoid “E,” it sets the P0773 code. This code applies to various OBD-II compliant vehicles with automatic transmissions, including models from Ford, Chrysler, Dodge, Honda, Toyota, and more. While generic, specific diagnostic and repair procedures can vary depending on the make, model, and year of your vehicle.
Symptoms of a P0773 Code
A P0773 code can manifest in several ways, including:
- Illuminated Check Engine Light: This is the most common indicator. Other warning lights, such as an Overdrive or transmission warning light, may also illuminate.
- Transmission Slipping: The gears may slip or change erratically while driving.
- Harsh Shifting: You might experience rough or abrupt gear changes.
- Transmission Overheating: The transmission fluid may overheat due to the malfunction.
- Reduced Fuel Economy: Improper shifting can lead to increased fuel consumption.
- Limp Mode: The vehicle might enter a “limp mode” to prevent further damage, limiting speed and functionality.
- Misfire-like Symptoms: In some cases, the engine might feel like it’s misfiring.
Common Causes of a P0773 Code
Several issues can trigger a P0773 code:
- Low Transmission Fluid: Insufficient fluid can prevent proper solenoid operation.
- Dirty or Contaminated Fluid: Debris or contaminants in the fluid can interfere with solenoid function.
- Clogged Transmission Filter: A restricted filter hinders fluid flow and affects solenoid performance.
- Faulty Shift Solenoid E: The solenoid itself may be malfunctioning due to electrical issues.
- Wiring Problems: Damaged, corroded, or shorted wiring in the solenoid circuit can cause the code.
- Connector Issues: Loose, damaged, or corroded connectors can disrupt the electrical connection.
- Transmission Valve Body Problems: Issues within the valve body can affect solenoid operation.
- Internal Transmission Failure: In more severe cases, internal mechanical problems within the transmission may be the root cause.
- Faulty PCM: While less common, a malfunctioning PCM can incorrectly set the code.
Troubleshooting Steps for a P0773 Code
Before starting any diagnostic work, consult your vehicle’s specific Technical Service Bulletins (TSBs) for potential known issues.
Basic Checks:
- Check Fluid Level and Condition: Ensure the transmission fluid is at the correct level and is not contaminated or burnt.
- Inspect Wiring and Connectors: Visually examine the wiring harness and connectors for damage, corrosion, or loose connections.
Advanced Diagnostics (require specialized tools and knowledge):
- Check Solenoid Resistance: Use a multimeter to test the resistance of shift solenoid E. Compare the reading to manufacturer specifications.
- Check Circuit Voltage: Verify the voltage supplied to the solenoid circuit.
- Test PCM: In rare cases, advanced diagnostic tools may be required to test the PCM for proper function.
Common Repairs for a P0773 Code
- Fluid and Filter Change: Often the first step, fresh fluid and a new filter can resolve issues related to contamination.
- Solenoid Replacement: If the solenoid is faulty, it will need to be replaced.
- Wiring Repair: Repair or replace any damaged or corroded wiring in the solenoid circuit.
- Connector Repair/Replacement: Address any loose or damaged connectors.
- Valve Body Repair/Replacement: If the valve body is faulty, it may require repair or replacement.
- Transmission Rebuild/Replacement: In severe cases of internal transmission damage, a rebuild or replacement may be necessary.
- PCM Replacement: Rarely, the PCM may need to be replaced if it’s the source of the problem.
Conclusion
The P0773 code indicates a potential problem with your transmission’s shift solenoid E electrical circuit. Addressing this issue promptly can prevent further damage and ensure the proper functioning of your vehicle. While some basic checks can be performed by DIYers, more advanced diagnostics and repairs are best left to qualified mechanics with the necessary expertise and equipment.
