Live Manual
Engine Error

P0170

Fuel Trim Malfunction (Bank 1)

Severity
High

Symptoms

Poor idle, engine hesitation, black smoke or lean stalling

Common Causes

  • Massive vacuum leak
  • Defective MAF sensor
  • Failing O2 sensor
  • Fuel pressure too high or too low

How to Fix

  1. 1 Smoke test for intake vacuum leaks
  2. 2 Clean or replace MAF sensor
  3. 3 Test and replace Bank 1 O2 sensor
  4. 4 Check fuel pump pressure
Estimated Repair Cost USD
$80 $800

MAF sensor: 150 - 300; Fuel pump: 400 - 800