P2189
System
Powertrain (Fuel/Air)
Scanner required
Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

System Too Rich at Idle (Bank 1)

Understand P2189, common causes, and the right TOPDON scanner to diagnose it.

Rich mixture at idle only. May indicate leaking injector, rich idle trim, or EVAP purge stuck open.

Common symptoms

  • Rough idle
  • Black smoke
  • Fuel smell at idle

Typical causes

  • Leaking injector at idle
  • EVAP purge valve stuck open
  • Faulty coolant temp sensor reading cold

What scanner do you need?

Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

Use live data and freeze frame to confirm the fault before replacing parts. ABS, SRS, and network U-codes usually require a full-system scanner.

Diagnostic tips

  • Record freeze frame data when the code first sets
  • Clear the code only after fixing the root cause
  • Check for related pending codes that point to a common issue
  • Verify battery voltage is above 12.4V before chasing sensor codes

Recommended TOPDON scanners

Frequently asked questions

Can I diagnose P2189 with a basic code reader?
P2189 may set in the engine module, but related diagnostics often benefit from an enhanced or full-system scanner with live data and freeze frame.
Is it safe to drive with P2189?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.