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DTC codes / Mazda codes / P1702

P1702 · MazdaTransmission Range Sensor Circuit Intermittent

P1702 on a Mazda means the Transmission Control Module (TCM) has detected an intermittent fault in the Transmission Range Sensor (TRS) circuit, which tells the computer which gear the selector is in. The TCM sees the range signal drop out or jump between positions for brief moments, even though the shifter itself has not moved.

SystemPowertrain
Code typeMazda specific
SeverityMedium
Fix difficultyIntermediate
AreaTransmission

Symptoms you may notice

  • The gear indicator on the instrument cluster may flash or show the wrong position.
  • The transmission may hesitate, slip, or shift harshly when the range signal glitches.
  • The engine may crank but not start in Park or Neutral because the TCM is unsure of the selector position.
  • The reverse lights may flicker or fail to come on when Reverse is selected.
  • The vehicle may enter limp mode or refuse to shift out of a single gear.
  • Often no symptoms besides the warning light, especially if the intermittent fault is brief.

Common causes, most likely first

  1. Worn or contaminated Transmission Range Sensor (TRS) internal contacts.
  2. Loose, corroded, or chafed wiring in the TRS circuit, especially near the transmission connector.
  3. Poor ground connection for the TRS or TCM.
  4. Moisture or fluid intrusion into the TRS connector or sensor housing.
  5. A misadjusted TRS linkage or selector cable that does not align the sensor with the detents.
  6. A failing TCM that intermittently misreads the TRS signal (less common).

How to diagnose and fix it

  1. Scan all modules for stored and pending codes, and record freeze-frame data for P1702 to see the conditions when it set.
  2. Inspect the TRS connector and wiring for corrosion, chafing, or loose pins, and repair as needed.
  3. Check the TRS ground circuit for excessive resistance and clean or tighten the ground point.
  4. Verify the TRS alignment by checking that the sensor voltage or resistance matches each selector position, and adjust the linkage if it is off.
  5. Back-probe the TRS signal wire at the TCM and wiggle the harness to look for intermittent drops while watching live data.
  6. If the sensor is original and shows erratic readings, replace the TRS and recheck the circuit.
  7. Clear the code and perform a road test with live data monitoring to confirm the fault does not return.

Why P1702 is often a wiring fault

  • The TRS is a wear item, but on many Mazdas the intermittent signal comes from a corroded connector pin rather than the sensor itself, so always inspect the plug before condemning the part.
  • A misadjusted selector cable can make the TRS report an in-between position that the TCM flags as intermittent, even though the sensor is electrically healthy.
  • P1702 can be set by a low battery or voltage spike that momentarily disrupts the TCM, so check charging system health if the code appears after jump-starting.
  • The TCM may store P1702 without ever illuminating the check engine light if the fault is very brief, so a pending code scan is essential during routine service.
  • Do not confuse P1702 with P0705 or P0706, which are hard circuit failures; P1702 specifically indicates an intermittent condition that may not be present during a static test.

Can I keep driving with P1702?

You can usually drive the car to a shop, but avoid relying on the gear indicator and be prepared for harsh shifts or a no-start condition. If the transmission enters limp mode or the engine will not crank in Park, stop driving and have the vehicle towed.

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

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