P0773 — Shift Solenoid “E” Electrical #

The code label may vary depending on the vehicle manufacturer (OEM). Below are known label variations for this DTC:

• Toyota: Shift Solenoid “E” Electrical (Shift Solenoid Valve SL)
• Lexus: Shift Solenoid “E” Electrical Malfunction
• Honda/Acura: Shift Solenoid “E” Circuit Electrical
• Nissan: Shift Solenoid “E” Electrical Fault

Summary of DTC P0773 #

P0773 is a generic OBD-II powertrain code indicating an electrical issue detected by the transmission control module (TCM) in the shift solenoid “E” circuit. In automatic transmissions, solenoids are electronically controlled valves that direct hydraulic fluid to engage specific gears. When the TCM detects an abnormal voltage or resistance in the “E” shift solenoid’s electrical circuit, it stores this code and may trigger the check engine light. This condition can affect shift quality or cause the transmission to enter a fail-safe mode. The issue may stem from wiring, the solenoid itself, or even the TCM.

Common Symptoms for Code P0773 #

When P0773 is active, the driver may notice a variety of symptoms impacting both drivability and transmission performance. These signs can range from subtle irregularities to more pronounced failures, depending on the severity and progression of the underlying fault.

• Check Engine Light illuminated
• Harsh or delayed gear shifts
• Transmission stuck in a single gear (“limp” or fail-safe mode)
• Reduced fuel efficiency
• Possible hesitation or slipping when accelerating
• Erratic shifting or inability to shift to certain gears

Probable Causes for DTC P0773 #

Diagnosing the root cause of P0773 involves considering several possibilities. While solenoid failure is common, electrical and control module issues are not uncommon. Here’s what most often triggers this DTC, ranked by likelihood:

1. Faulty Shift Solenoid “E”: The solenoid may be stuck, open, or shorted.
2. Wiring Issues: Corroded, damaged, or loose connections in the solenoid circuit harness.
3. Connector Problems: Poor electrical contact or contamination at the solenoid or TCM connectors.
4. Transmission Fluid Contamination: Old, dirty, or low fluid can affect solenoid operation.
5. Failed Transmission Control Module (TCM): Rare, but possible if all else checks out.

Step-by-Step Diagnostic Procedure for Code P0773 #

A systematic approach is crucial to accurately pinpoint the cause of P0773. Skipping steps or making assumptions can lead to unnecessary repairs. Here’s a technician-approved diagnostic pathway:

• Verify the code with a professional OBD-II scanner and note any related transmission codes.
• Visually inspect the transmission harness and connectors for damage, corrosion, or loose pins.
• Check transmission fluid condition and level. Address any discrepancies before proceeding.
• Test the resistance of Shift Solenoid “E” using a multimeter. Compare to OEM specifications.
• Command the solenoid on/off with a scan tool to confirm operation (if supported).
• Inspect the wiring between the TCM and solenoid for continuity and shorts to ground or power.
• If all else passes, consider TCM diagnostics or programming updates as per manufacturer instructions.

Possible Repairs for Code P0773 #

Once the actual fault is identified, repairs should directly address the underlying cause. Attempting to “clear” the code without proper repairs will only lead to recurring issues. Typical solutions include:

• Replacing the faulty Shift Solenoid “E”
• Repairing or replacing damaged wiring or connectors in the solenoid circuit
• Cleaning contaminated connectors and applying dielectric grease if appropriate
• Flushing and replacing dirty or degraded transmission fluid
• Replacing or updating the TCM (only if confirmed faulty after all other steps)

Can You Drive with Code P0773? #

Driving with an active P0773 code is generally not recommended. While the vehicle may still move, it could be stuck in a single gear or shift unpredictably, which can be dangerous in traffic. Continued driving may further damage the transmission or related electrical components. If you experience harsh shifting, hesitation, or are unable to shift gears reliably, have the vehicle inspected and repaired as soon as possible.

Vehicles Most Commonly Affected by P0773 #

P0773 appears most frequently on vehicles using electronically controlled automatic transmissions, especially in certain models from the following manufacturers:

• Toyota and Lexus (notably with Aisin automatic transmissions)
• Nissan and Infiniti
• Honda and Acura (select models)
• Some Mazda and Ford models with shared transmission platforms

This code can appear in various other makes, but these are the most regularly reported.

Common Mistakes & Best Practices for P0773 #

Misdiagnosis is a frequent pitfall with P0773. Addressing the symptoms rather than the root cause often leads to repeat repairs. To avoid frustration and unnecessary costs:

• Do not replace the shift solenoid without first testing wiring and connectors.
• Avoid using generic scan tools for deep diagnostics — OEM-level tools provide the most accurate data.
• Always verify transmission fluid quality and level before electrical diagnostics.
• Don’t overlook the possibility of TCM faults, especially if the solenoid and wiring test good.
• Clear codes and perform a road test after repairs to confirm resolution.

Quick FAQ on DTC P0773 #

Q1: Will clearing the code fix my transmission?
A1: No. Clearing the code will only reset the check engine light temporarily. The underlying electrical issue must be repaired for a lasting fix.

Q2: Is it expensive to repair P0773?
A2: Costs vary. Replacing a solenoid or repairing wiring is generally less expensive than replacing a TCM or performing major transmission work. A proper diagnosis is essential to avoid unnecessary expenses.