OBD Guide
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P1156

HO2S Rich Average Bank 2 Sensor 1

P1156 is an OBD-II diagnostic trouble code meaning: HO2S Rich Average Bank 2 Sensor 1. Common causes: oxygen sensor (ho2s) malfunction, fuel leaking from injectors. Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–89 (est.)

Symptoms

  • Increased fuel consumption
  • Black smoke from the exhaust pipe
  • Unstable engine idling
  • Loss of engine power
  • Smell of gasoline from the exhaust pipe

Causes

  • Oxygen sensor (HO2S) malfunction
  • Fuel leaking from injectors
  • Increased pressure in the fuel rail
  • Dirty or faulty MAF (mass air flow sensor)
  • Problems with the EVAP system

How to Fix

  1. Check the condition and operation of the oxygen sensor bank 2, sensor 1
  2. Check injectors for leaks
  3. Check the fuel pressure in the rail
  4. Clean or replace the mass air flow sensor if necessary
  5. Check the EVAP system for leaks

Related codes

P1157P0172P0175

Error P1156 by Vehicle Brand

BMWBuickCadillacChevroletChryslerGMGMCOldsmobileSaturnVolkswagen

FAQ

What does the P1156 code mean?

P1156 is an OBD-II diagnostic trouble code that indicates: HO2S Rich Average Bank 2 Sensor 1

What causes a P1156 error code?

The most common causes of P1156 include: Oxygen sensor (HO2S) malfunction; Fuel leaking from injectors; Increased pressure in the fuel rail; Dirty or faulty MAF (mass air flow sensor).

How do I fix a P1156 diagnostic trouble code?

To fix P1156: Check the condition and operation of the oxygen sensor bank 2, sensor 1. Check injectors for leaks. Check the fuel pressure in the rail. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1156?

Yes, but get it checked soon

How much does it cost to fix P1156?

The estimated repair cost for P1156 is $17–89. Actual cost depends on your vehicle, location, and labor rates.

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