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DTC codes / P09xx · Transmission / P0935

P0935Hydraulic Pressure Sensor Circuit High

P0935 means the transmission control module (TCM) sees a voltage on the hydraulic pressure sensor signal circuit that is higher than the sensor can legitimately produce under any operating condition. The TCM compares this signal against expected ranges and flags the circuit as high, which usually indicates an open circuit, a short to voltage, or a failed sensor.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaTransmission

Symptoms you may notice

  • Illumination of the check engine light or transmission warning light, often with no other symptoms besides the warning light
  • Harsh or delayed transmission shifts as the TCM substitutes a default pressure value
  • The transmission may enter limp mode, holding a single gear or refusing to shift
  • Erratic shift quality or slipping that varies with temperature and load
  • A stored code P0935 with no drivability complaint at all in some vehicles

Common causes, most likely first

  1. An open or high-resistance connection in the sensor signal circuit, including a broken wire or corroded terminal
  2. A short to voltage on the signal circuit, often from chafed wiring near a heat source or moving component
  3. A failed hydraulic pressure sensor that internally reads high or has an open internal element
  4. A poor ground connection at the sensor or TCM, causing a reference voltage offset
  5. A faulty TCM or a software calibration issue that misinterprets the sensor signal
  6. Contamination or debris in the hydraulic circuit that physically damages the sensor diaphragm

How to diagnose and fix it

  1. Connect a scan tool and record the freeze-frame data and live sensor voltage to confirm the signal is stuck high or out of range
  2. Inspect the sensor connector and wiring harness for corrosion, chafing, or a loose pin, and repair any damage found
  3. Measure resistance and voltage on the signal circuit with a digital multimeter, checking for an open circuit or a short to voltage
  4. Verify the sensor ground circuit has less than one ohm of resistance to the TCM ground
  5. If wiring and grounds are good, replace the hydraulic pressure sensor and clear the code
  6. Check for a TCM software update or calibration bulletin that addresses false high-pressure sensor codes
  7. After repair, clear the code and perform a relearn or adaptation drive cycle to confirm the fix

What a high pressure sensor code really means

  • A high signal voltage almost never means the actual hydraulic pressure is too high; it means the circuit is open or shorted to voltage, so do not replace the pump or valve body first.
  • Corroded terminals inside the sensor connector are a more common cause than a failed sensor, especially on vehicles driven in wet or salty conditions.
  • A chafed signal wire that shorts to a nearby 12-volt feed can set P0935 intermittently, so wiggle-test the harness while watching live data.
  • Some transmissions use a shared reference voltage for multiple sensors, and a fault in one sensor can pull the reference high and set this code on another circuit.
  • After replacing the sensor, the TCM may need a pressure adaptation relearn before the code stays cleared and shift quality returns to normal.

Can I keep driving with P0935?

You can usually drive the vehicle short distances to a repair shop, but avoid heavy acceleration or towing because the transmission may be operating on default pressure and can shift harshly or slip. If the transmission enters limp mode or refuses to shift, stop driving and have it 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 all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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