Clearing fault codes is simple — but understanding why they return is what separates beginners from real diagnostics.
In this lesson, you’ll learn the correct way to clear codes and what it actually means when a fault code comes back immediately.
This content is for members only.
Correct way to clear fault codes
Recommended procedure:
- Ignition ON
- Engine OFF
Some scanners allow clearing codes with the engine running — but this is not the standard method.
⚠️ Why fault codes come back
If you clear a fault code and it comes back immediately, it does NOT mean:
- Your scanner is broken ❌
It means:
- The problem is still present ✅
Real example
Let’s say you have:
- Broken wiring to an oxygen sensor
What happens:
- ECU cannot communicate with the sensor
- Fault condition is already met
👉 Even if you clear the code:
- ECU instantly detects the same issue
- Code is stored again immediately
Key diagnostic insight
Clearing codes does not fix the problem.
It only removes the stored fault temporarily.
👉 If the root cause is still there, the code will return.
When clearing codes makes sense
- After repairing a fault
- To verify if the issue is fixed
- To reset warning lights after repair
Final takeaway
- Clearing codes = reset, not repair
- Returning code = active problem
- Always fix the cause, not the code
