OBD Guide

P1159

Air/Fuel Ratio Sensor 1 AFS+ Terminal Low Voltage

P1159 is an OBD-II diagnostic trouble code meaning: Air/Fuel Ratio Sensor 1 AFS+ Terminal Low Voltage. Common causes: open or short circuit in the sensor circuit, air/fuel ratio sensor malfunction. Estimated repair cost: $33–89.

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

FAQ

What does the P1159 code mean?

P1159 is an OBD-II diagnostic trouble code that indicates: Air/Fuel Ratio Sensor 1 AFS+ Terminal Low Voltage

What causes a P1159 error code?

The most common causes of P1159 include: Open or short circuit in the sensor circuit; Air/fuel ratio sensor malfunction; Poor contact in the sensor connector; Problems with sensor ground.

How do I fix a P1159 diagnostic trouble code?

To fix P1159: Check the integrity of the wiring to the sensor. Check the connections in the sensor connector. Measure resistance and voltage at the sensor. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1159?

Yes, but get it checked soon

How much does it cost to fix P1159?

The estimated repair cost for P1159 is $33–89. Actual cost depends on your vehicle, location, and labor rates.

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