Lean Mass Air Flow Sensor Causing Code P0170 on Toyota 4Runner

Submitted by Vehicle Owner · May 29, 2025
Published by RepairPal

Problem overview

Occasionally, the mass air flow sensor can go lean and set a code P0170 for fuel system lean. This in not an oxygen sensor problem. If there are no vacuum leaks, the mass air flow sensor may need to be replaced. Our technicians remind us to use a factory part because the aftermarket rebuilds are very inconsistent.

5 people reported this problem
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Toyota 4Runner vehicles with this problem

Average mileage: 311,000 miles
(311,000 - 311,000)

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