Transmission Friction Element Slip Detected
Code P079E indicates that the transmission control module (TCM) has detected unexpected slip in one or more friction elements (clutches or bands) inside the automatic transmission. This slip occurs when the transmission cannot maintain proper clamping force, often due to low fluid pressure, worn friction material, or hydraulic circuit issues. If left unaddressed, it can lead to severe internal damage and transmission failure.
01. Most Common Causes
- Low transmission fluid level or degraded fluid
- Worn or burnt friction plates/bands
- Faulty transmission valve body or solenoid
- Clogged transmission filter or fluid passages
02. Symptoms You Will Notice
- Delayed or harsh gear engagement
- Transmission slipping while driving
- Check Engine Light illuminated
- Overheating transmission
03. Step-by-Step Diagnosis
Step 1: Check transmission fluid level and condition; top off or replace if necessary.
Step 2: Scan for additional codes and perform a transmission pressure test.
Step 3: Inspect wiring and connectors to the transmission solenoids and sensors.
Step 4: Perform a transmission stall test to isolate slipping components.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
No, continued driving can cause severe internal damage and complete transmission failure. Have it inspected immediately.
How much does it cost to fix?▼
Costs vary widely: a fluid change and filter may cost $150-$300, while a valve body replacement or transmission rebuild can range from $1,000 to $4,000+.