Low, degraded or burnt transmission fluid reducing clutch pressure and friction; Worn clutch or brake pack friction plates in the element concerned; Faulty shift solenoid or pressure control solenoid for that element; Valve body wear, sticking valves or internal fluid leaks causing low apply pressure; Blocked transmission filter or low line pressure from a weak pump; Faulty input or output speed sensor giving false slip readings, or damaged wiring and connectors; Outdated transmission control software where the manufacturer has issued a revised calibration for this fault.

P079E

Transmission Friction Element E Slip Detected.

Generic
Powertrain
Generic code
High severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
7: AreaTransmission
9E: FaultThe specific fault in that area

What it means

P079E is a generic transmission code meaning the control unit has detected slip on friction element E, which is a clutch or brake pack inside the automatic gearbox. The control unit compares input and output shaft speeds against the gear it has commanded and sets the code when the ratio shows the element is not holding as expected. Which clutch or brake 'E' refers to depends on the gearbox model, so check the manufacturer's information for that transmission.

Symptoms

Engine revs flaring or rising without matching acceleration during a gearshift
Delayed, harsh or slipping shifts into certain gears
Loss of drive in one or more gears
Gearbox stuck in limp mode or a fixed gear
Transmission warning light or engine warning light on
Burnt smell from the transmission fluid

Possible causes

Low, degraded or burnt transmission fluid reducing clutch pressure and frictionlikely
Worn clutch or brake pack friction plates in the element concernedlikely
Faulty shift solenoid or pressure control solenoid for that elementpossible
Valve body wear, sticking valves or internal fluid leaks causing low apply pressurepossible
Blocked transmission filter or low line pressure from a weak pumppossible
Faulty input or output speed sensor giving false slip readings, or damaged wiring and connectorspossible
Outdated transmission control software where the manufacturer has issued a revised calibration for this faultrare

How to diagnose

Read all stored codes and freeze frame data, noting gear, temperature, speed and load when the fault set, and look for related speed sensor or solenoid codes
Check the transmission fluid level and condition (colour, smell, debris) using the method specified for that gearbox, as some are sealed and need a set temperature
Inspect the transmission wiring, connectors and speed sensors for damage, oil contamination or corrosion
Use live data to compare input and output shaft speeds in each gear and see which gear shows slip
Check for any manufacturer service information or software updates relating to this code and gearbox
Test line pressure and solenoid operation and resistance against the manufacturer's specifications
Check the fluid and pan for metal or friction material, which points to internal wear
Inspect the valve body and clutch packs if the above points to an internal fault

How to fix

Correct the fluid level and replace degraded fluid and filter with the specified type if the gearbox is serviceable
Repair or replace damaged wiring, connectors or faulty speed sensors
Replace the faulty solenoid or repair the valve body as diagnosed
Overhaul or replace the transmission, including the worn clutch or brake pack, if internal wear is confirmed
Apply a manufacturer-released transmission software update where one is known to address the fault

Can I keep driving?

High severity

Avoid driving, or keep it to a minimum, as continued slip quickly burns clutch material and can destroy the gearbox. If you must move the car, drive gently and have it inspected promptly.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.