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DTC codes / Honda codes / P1793

P1793 · HondaAutomatic Transmission System Malfunction

P1793 on Honda vehicles indicates that the transmission control module (TCM) has detected a general malfunction within the automatic transmission system, often related to the lock-up clutch or shift solenoid circuit. The TCM monitors electrical and hydraulic performance and sets this code when it sees an unexpected condition that prevents normal operation.

SystemPowertrain
Code typeHonda specific
SeverityMedium
Fix difficultyProfessional
AreaTransmission

Symptoms you may notice

  • The check engine light or transmission warning light illuminates on the dashboard.
  • The transmission may enter limp mode, limiting gear selection to one or two gears.
  • Harsh or delayed shifting, especially when accelerating or decelerating.
  • The torque converter clutch may fail to engage or disengage, causing shuddering at highway speeds.
  • Often no symptoms besides the warning light, especially if the fault is intermittent.

Common causes, most likely first

  1. Faulty shift solenoid or lock-up solenoid, or its wiring connector.
  2. Deteriorated transmission fluid causing hydraulic pressure issues.
  3. Internal transmission mechanical wear, such as a sticking valve body or worn clutch packs.
  4. Poor electrical connection at the TCM or transmission harness.
  5. A failing transmission control module (TCM) itself, though less common.
  6. Damaged or corroded wiring between the TCM and transmission solenoids.

How to diagnose and fix it

  1. Check transmission fluid level and condition; top off or replace if dark or burnt.
  2. Inspect the transmission wiring harness and connectors for damage or corrosion.
  3. Perform a battery voltage and ground check to ensure the TCM receives stable power.
  4. Use a scan tool to retrieve transmission-specific codes and freeze-frame data.
  5. Test the shift solenoids and lock-up solenoid with a multimeter for resistance and continuity.
  6. If electrical tests are inconclusive, perform a hydraulic pressure test or consult a transmission specialist for internal diagnosis.

What P1793 Really Means for Your Honda

  • This code often appears when the lock-up clutch solenoid circuit is failing, but the root cause can be as simple as a dirty transmission fluid change that restores proper hydraulic pressure.
  • A weak battery or poor ground connection can cause the TCM to set P1793 intermittently, so always verify power and ground before replacing expensive components.
  • Some Honda models set P1793 when the transmission range sensor is misaligned, leading to incorrect gear position signals that the TCM interprets as a general malfunction.
  • The code does not always indicate a major internal transmission failure; many cases are resolved by repairing a chafed wire in the harness near the transmission case.

Can I keep driving with P1793?

You can drive cautiously to a repair shop if the transmission shifts normally, but avoid heavy acceleration or towing. If the transmission is in limp mode or shifting harshly, stop driving and have it towed to prevent further 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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