What it means
The transmission control module detected slip in friction element E. The code identifies the element; its design and function depend on the transmission.
At a glance
- Usually lights the check-engine light
How it works
The transmission control module checks whether friction element E holds when the transmission commands it to apply, using speed signals and gear-ratio calculations. P079E means element E is slipping beyond the module’s expected limit; the element’s role varies by transmission design.
Common causes
Most likely first.
- Worn or damaged friction element E
- Low or degraded transmission fluid
- Hydraulic pressure loss or internal leakage
- Valve body or control fault affecting element application
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
How to diagnose it
- Record freeze-frame data and review commanded gear, input speed, and output speed to identify when the module detected element E slip.
- Check fluid level and condition according to the vehicle maker’s procedure, because insufficient or degraded fluid can impair element E application.
- Inspect transmission connectors and wiring for corrosion, looseness, or damage that could interfere with element E control.
- Use live data during a controlled drive to see whether the actual ratio departs from the commanded ratio when element E should be holding.
- If the slip is confirmed, test hydraulic pressure and inspect valve-body or control operation against the manufacturer's specification.
- If external and hydraulic causes are ruled out, inspect element E friction parts and apply seals for wear or internal leakage.
Common fixes
- Set the fluid to the specified level or replace degraded fluid with the correct type.
- Repair damaged wiring or restore a clean, secure connector connection.
- Repair a valve-body fault or internal hydraulic leak affecting element E.
- Replace worn element E friction parts or failed apply seals.
Can I keep driving?
Limit driving and avoid heavy loads or acceleration, as ongoing slip can overheat the transmission and worsen internal damage. If the vehicle loses a gear, shifts erratically, or enters limp mode, stop driving and arrange recovery.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.