Powertrain, generic (extended)

P274D Transmission Fluid Temperature Sensor C Circuit High

Check engine lightOn
EmissionsNot relevant
Drive cycleRequired
Limp modeNo

P274D is set when the sensor C signal climbs above its highest permitted value. On a thermistor supplied with 5 V via a resistor, that happens when the circuit opens – a broken wire, a corroded or unplugged connector – or when the signal line touches a voltage source; the display would then show fluid colder than any real climate produces. No manufacturer documents P274D publicly. For the main sensor, Ford's 2012 strategy uses above 4.6 V, and GM's 2023 dual-clutch module above 4745 mV for its sump sensor, both as electrical limits rather than temperatures. Until the fault is cleared the transmission may keep a cold-fluid strategy with delayed converter lock-up or more cautious clutch control.

Likely causes

Open circuit in sensor C lead or connector
Signal lead shorted to voltage
Sensor C open internally

Symptoms

  • Warning lamp
  • Temperature C shows an extremely cold value
  • Late converter lock-up or cautious shifting

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–900
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

trans fluid temp sensor cwiring harness

Related codes

P274AP274BP274CP274EP0713

References: law.cornell.edu, newtonnet.co.uk, gsi.ext.gm.com.