P077E
Transmission Fluid Temperature Measurement System - Multiple Sensor Correlation
Modern transmissions can have two or more ATF temperature sensors (sump, cooler return, valve body). After a long key-off soak they should all read approximately the same ambient. The TCM detects an implausible spread between sensors — one of them drifts or is wired wrong.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Common causes
Ordered by how often each turns out to be the cause.
- One sensor drifting outside toleranceCommon
- Sensors swapped after servicePossible
Parts involved
- Atf Temperature Sensors
P077E is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.