P0174 Toyota Camry V6: System Too Lean (Bank 2)

Quick Answer: What is P0174?

On a Toyota Camry V6, the P0174 code means the Engine Control Module (ECM) has detected too much air and not enough fuel on Bank 2 (the front bank of cylinders). This "lean" condition forces the computer to spray extra fuel to compensate, which often results in poor performance and high fuel consumption.

Severity: MEDIUM. Running lean can cause "engine knock" and spark plug damage. If you ignore it, the excess heat can eventually damage your valves or the catalytic converter on the front exhaust manifold.

Common Symptoms

Check Engine Light: On with code P0174 (and possibly P0171).
Rough Idling: Especially when the engine is cold or at a stoplight.
Engine Hesitation: A "flat spot" when accelerating from a stop.
Decreased Gas Mileage: The car consumes more fuel as the ECM tries to correct the mixture.

Most Likely Causes

Vacuum Leak (45%): Cracked rubber hoses or a leaking intake manifold gasket on the Bank 2 side.
Dirty MAF Sensor (30%): While a dirty MAF usually causes both P0171 and P0174, it can occasionally trigger one before the other.
Faulty Air-Fuel (A/F) Sensor: The upstream sensor on Bank 2 is reporting incorrect oxygen levels.
Clogged Fuel Injectors: Specifically the injectors on the front bank of the V6 engine.

Detailed Repair Cost Breakdown

Estimates for Toyota Camry V6 models (3.0L, 3.3L, and 3.5L) in the US market:

Component / Task	Aftermarket Part	OEM Toyota/Denso	Labor Time	Difficulty
Vacuum Hose Repair	$5 - $15	N/A	0.5 - 1.0 hr	Very Easy
A/F Sensor (Bank 2 Upstream)	$95 - $140	$180 - $260	0.5 - 1.0 hr	Easy (DIY)
Intake Gasket Set	$35 - $60	$90 - $130	2.5 - 4.0 hrs	Hard

How to Fix P0174 on a Toyota Camry V6

1. Check the Intake Bellows

The large rubber hose connecting the air filter box to the engine often develops cracks in the ribbed sections. Since Bank 2 is at the front, check the manifold gaskets and small vacuum lines near the radiator side first. Spraying a little soapy water (or using a smoke machine) will quickly reveal bubbles where air is being sucked in.

2. Clean the MAF Sensor

If you have both P0171 and P0174, the problem is almost certainly the MAF sensor. Remove it and spray the internal wires with MAF Cleaner. This is a 10-minute fix that solves the problem in a large percentage of Toyota V6 engines.

3. Inspect the PCV Hose

On the Camry V6, the PCV (Positive Crankcase Ventilation) hose can become brittle and crack. A leak here acts as a large vacuum leak that primarily affects the Bank 2 fuel trims. A $10 replacement hose is a common solution for this code.