P0174 on a Toyota RAV4
P0174 means system Too Lean (Bank 2). On the RAV4, a few causes come up far more than others.
What P0174 usually means on a RAV4
P0174 is the bank 2 version of a lean code and only appears on V6 RAV4s. It signals that the rear cylinder bank is running lean. When it shows up on its own, look for something specific to that bank — a cracked rear PCV hose or a leaking rear intake gasket. When it pairs with P0171, the cause is usually shared across both banks, like a dirty MAF or low fuel pressure.
Most common causes on the RAV4
- Bank 2 vacuum leak
A cracked rear PCV line or leaking rear intake gasket leans only the firewall-side bank.
- Dirty MAF (with P0171)
When both banks read lean, a contaminated MAF is the shared cause.
- Failing bank 2 AF sensor
The rear Denso sensor is often original and slows with age.
- Low fuel pressure
A weak pump leans both banks under load, so check pressure if trims climb everywhere.
What P0174 costs to fix on a RAV4
A standalone P0174 means hunting a rear-bank vacuum leak, which is fiddly because the hoses hide behind the intake, so budget for diagnostic time. A shared cause with P0171 is usually cheaper to isolate. A smoke test is the quickest path to the leak.
Year, engine and mileage change the answer. Start a case and Redline weighs these causes against what your car shows, then names the check that would settle it.
Other codes on the Toyota RAV4
Related symptoms
Toyota RAV4 problems & recalls by year
Based on widely reported patterns for this model; individual causes vary by year, engine and history. Generic P0174 behavior is covered on the main P0174 page. Confirm with a scan tool before buying parts.
P0174 on your RAV4?
Every problem becomes a Case. Tell Redline what your RAV4 is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.