Faulty transmission fluid temperature sensor, either internal or external, providing a skewed signal.; Damaged or corroded wiring or connector at one of the temperature sensors.; Low or contaminated transmission fluid affecting heat transfer and sensor correlation.; Internal transmission mechanical issues causing uneven heating that the sensors detect.; A software calibration issue in the transmission control module (TCM) requiring an update.; Failed TCM or a fault in its internal processing of sensor signals.

DTC codes / P07xx · Transmission / P077E

P077ETransmission Fluid Temperature Measurement System Multiple Sensor Correlation

P077E indicates that the transmission control module has detected a disagreement between multiple transmission fluid temperature sensors, or between a sensor and a calculated model, beyond the allowed tolerance. The computer compares readings from two or more sensors and flags the code when their correlation falls outside the expected range for a set time.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaTransmission

Symptoms you may notice

Illumination of the check engine light or transmission warning light, often with no other symptoms.
Harsh or delayed shifting as the transmission enters a fail-safe strategy.
Erratic torque converter clutch operation or shudder during light acceleration.
Incorrect fluid temperature reading on a scan tool, sometimes showing an implausible value.
In rare cases, the transmission may default to a fixed gear or limit engine power.

Common causes, most likely first

Faulty transmission fluid temperature sensor, either internal or external, providing a skewed signal.
Damaged or corroded wiring or connector at one of the temperature sensors.
Low or contaminated transmission fluid affecting heat transfer and sensor correlation.
Internal transmission mechanical issues causing uneven heating that the sensors detect.
A software calibration issue in the transmission control module (TCM) requiring an update.
Failed TCM or a fault in its internal processing of sensor signals.

How to diagnose and fix it

Connect a scan tool and record freeze-frame data and all transmission fluid temperature sensor readings to identify which sensor is out of range.
Inspect the transmission fluid level and condition; top off or replace fluid if it is low or contaminated.
Check the wiring and connectors at each temperature sensor for damage, corrosion, or loose pins.
Perform a resistance test on each temperature sensor and compare to the manufacturer's specification.
If a sensor is faulty, replace it according to service information, then clear codes and verify the correlation returns to normal.
Check for technical service bulletins (TSBs) or software updates for the TCM that address sensor correlation issues.
If all sensors and wiring test good, diagnose the TCM and internal transmission components as the remaining possibilities.

Why multiple temperature sensors disagree

A common oversight is assuming the code always means a failed sensor, but low fluid level or a restricted cooler can cause uneven temperatures that trigger the correlation fault.
Some vehicles use a calculated fluid temperature model instead of a second sensor, so the code can set when the model and the actual sensor drift apart due to a software calibration issue.
Corroded pins in a connector often cause intermittent correlation faults that do not appear during a simple resistance check; a wiggle test while monitoring live data is more reliable.
After replacing a sensor, the TCM may need a relearn or adaptation reset before the code stays cleared, which technicians sometimes miss.
A failing thermostat or cooling system issue can affect transmission fluid temperature indirectly, leading to correlation faults that are not caused by the transmission itself.

Can I keep driving with P077E?

You can usually drive the vehicle to a repair shop, but avoid heavy loads or aggressive acceleration because the transmission may be in a fail-safe mode. If shifting becomes harsh or the vehicle enters limp mode, stop driving and seek professional diagnosis.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.