OBD Guide

P1159

Air/Fuel Ratio Sensor 1 AFS+ Terminal Low Voltage

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$33–89 (est.)

Symptoms

  • Increased fuel consumption
  • Unstable engine operation at idle
  • Loss of engine power
  • Check Engine Light Illuminates
  • Increased emissions of harmful substances

Causes

  • Open or short circuit in the sensor circuit
  • Air/fuel ratio sensor malfunction
  • Poor contact in the sensor connector
  • Problems with sensor ground
  • Engine ECU malfunction

How to Fix

  1. Check the integrity of the wiring to the sensor
  2. Check the connections in the sensor connector
  3. Measure resistance and voltage at the sensor
  4. Replace air/fuel ratio sensor if necessary
  5. Check and, if necessary, replace the engine ECU

Related codes

Error P1159 by Vehicle Brand