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DTC codes / Nissan codes / P1655

P1655 · NissanTMA or TMB Signal Line Fault

P1655 on Nissan vehicles indicates that the engine control module (ECM) has detected a fault on the signal line for the torque management advance (TMA) or torque management brake (TMB) system, which are used to coordinate engine torque reduction during transmission shifts or traction control events. The ECM monitors the expected voltage or signal pattern on these dedicated circuits and sets the code when the signal is missing, out of range, or implausible.

SystemPowertrain
Code typeNissan specific
SeverityMedium
Fix difficultyProfessional
AreaComputer and output circuits

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Harsh or delayed transmission shifts due to lost torque management during gear changes
  • Reduced engine power or a limp-home mode in some driving conditions
  • Inconsistent idle quality or slight hesitation when the air conditioning engages
  • Traction control or stability control warning light may also illuminate on models with integrated systems

Common causes, most likely first

  1. Damaged or corroded wiring in the TMA or TMB signal circuit, especially near the transmission or engine harness connectors
  2. Failed torque management solenoid or actuator on the transmission valve body
  3. Loose or contaminated electrical connector at the ECM or transmission control module (TCM)
  4. Internal fault in the ECM or TCM driver circuit for the TMA/TMB signal line
  5. Aftermarket electrical accessories or poor grounds interfering with the signal reference voltage
  6. Transmission fluid contamination or low fluid level causing actuator performance issues that mimic a signal fault

How to diagnose and fix it

  1. Connect a scan tool and record all stored codes, freeze-frame data, and live TMA/TMB signal values to confirm the fault is active
  2. Visually inspect the TMA and TMB wiring harness for chafing, corrosion, or loose connectors, especially at the transmission and ECM
  3. Measure resistance and continuity on the signal line from the ECM to the transmission actuator, comparing to factory specifications
  4. Check for short circuits to ground or power on the signal circuit with a multimeter while wiggling the harness
  5. Test the torque management solenoid or actuator directly with a bidirectional scan tool or by applying battery voltage and listening for activation
  6. If the circuit and actuator test good, substitute a known-good ECM or TCM to rule out an internal driver fault
  7. Clear codes and perform a relearn or adaptation drive cycle, then verify the signal returns to normal and the code does not reset

What Nissan technicians check before replacing the TCM

  • A common oversight is a poor ground connection at the transmission bellhousing, which can corrupt the TMA/TMB signal reference and set P1655 without any visible wire damage.
  • Aftermarket remote starters or alarm systems tapped into the CAN bus or signal wiring frequently disturb the torque management circuit and trigger this code.
  • The TMA and TMB lines are often shared with other torque request signals, so a fault in a related system such as the anti-lock brake (ABS) module can set P1655 as a secondary code.
  • On some Nissan models, a low or failing battery can cause the ECM to misread the signal line during cranking, setting P1655 intermittently with no hard fault present.
  • Replacing the transmission valve body without first checking the signal line voltage at the ECM connector often leads to a repeat repair because the wiring fault remains.

Can I keep driving with P1655?

You can usually continue driving to a repair shop, but avoid heavy acceleration or towing because the loss of torque management can cause harsh shifts and extra transmission wear. If the engine enters limp mode or the transmission slips noticeably, stop driving and arrange a tow.

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 Nissan vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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