P0175 Toyota 4Runner
System Too Rich (Bank 2) · Powertrain Code · Medium · Repair: Moderate
What is P0175?
The engine is running rich on bank 2. Same causes as P0172 but affecting the opposite cylinder bank.
When the Toyota 4Runner triggers code P0175 (system too rich (bank 2)), it typically points to an issue in the powertrain system. Below you'll find the most common causes, symptoms, and repair options specific to the Toyota 4Runner.
This repair is rated moderate, meaning some experience and specialty tools required.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Toyota 4Runner.
Common Causes on Toyota 4Runner
- System running too rich bank 2 — same root causes as P0172 on V6 Toyota engines
- Contaminated MAF sensor affecting both banks
- Excessive fuel pressure from failing fuel pump regulator
- Large vacuum leak after MAF sensor causing ECM to add too much fuel
Symptoms
- Check Engine Light on
- Black exhaust smoke especially at idle
- Poor fuel economy
- Rough idle and hesitation
- Strong gasoline smell
Notes for Toyota 4Runner
P0175 only appears on V6/V8 Toyota models — on 4-cylinder models there is only bank 1 (P0172).