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DTC codes / Honda codes / P1773

P1773 · HondaAutomatic Transmission System Malfunction

P1773 on Honda vehicles indicates that the transmission control module (TCM) has detected a general malfunction within the automatic transmission system, often related to the shift solenoid valve circuit or hydraulic pressure control. The TCM monitors electrical current and response time from the solenoids and sets this code when the expected signal does not match actual conditions, triggering the check engine light and possibly limp mode.

SystemPowertrain
Code typeHonda specific
SeverityMedium
Fix difficultyProfessional
AreaTransmission

Symptoms you may notice

  • Check engine light or transmission warning light illuminated on the dashboard
  • Harsh or delayed shifting, especially when cold
  • Transmission stuck in a single gear (limp mode) or refusing to downshift
  • Slipping during acceleration or shuddering while driving
  • Often no symptoms besides the warning light, with normal driving behavior

Common causes, most likely first

  1. Faulty shift solenoid valve (linear solenoid) or its internal coil
  2. Deteriorated or contaminated automatic transmission fluid (ATF) causing solenoid sticking
  3. Damaged wiring harness or corroded connector at the transmission solenoid pack
  4. Failed transmission control module (TCM) or poor ground connection
  5. Internal transmission mechanical wear, such as a stuck valve body or worn clutch packs
  6. Low transmission fluid level due to a leak

How to diagnose and fix it

  1. Check transmission fluid level and condition; top off or replace if dark or burnt
  2. Inspect the solenoid pack connector and wiring for corrosion, chafing, or loose pins
  3. Perform a resistance test on each shift solenoid and compare to Honda specifications
  4. Use a scan tool to command each solenoid on and off while monitoring current draw and transmission response
  5. Replace the faulty solenoid or solenoid pack if electrical tests fail
  6. Clear the code and perform a relearn drive cycle to verify the repair
  7. If the code persists, diagnose internal hydraulic pressure or valve body issues with a pressure gauge

What Honda technicians check before replacing solenoids

  • A weak battery or poor ground can cause voltage spikes that mimic a solenoid fault, so always verify charging system health first.
  • Honda's TCM often logs P1773 when the linear solenoid current is out of range, but the root cause can be a clogged transmission filter rather than the solenoid itself.
  • After replacing a solenoid, the TCM may require a solenoid initialization or clutch relearn procedure using a factory scan tool to prevent repeat codes.
  • Intermittent P1773 codes that appear only in cold weather often point to fluid viscosity issues or a sticking valve body, not a failed electrical component.
  • Do not overlook the transmission range sensor or shift cable adjustment, as misalignment can trigger general transmission malfunction codes on Honda models.

Can I keep driving with P1773?

It is generally safe to drive short distances to a repair shop if the transmission shifts normally and the light is steady, but avoid heavy acceleration or towing. If the transmission enters limp mode or slips severely, stop driving to prevent internal damage.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Honda vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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