Subaru P1491: Positive Crankcase Ventilation (Blow-by) Function Problem

Is your scanner showing Subaru P1491?
No worries. We'll show you what it means and how to deal with it.

Presented by
Randy Worner

Subaru P1491: Positive Crankcase Ventilation (Blow-by) Function Problem

OVERVIEW
Severity
:
High
DIY Difficulty Level
:
Intermediate
Repair Cost
:
$150-$250
Can I Still Drive?
:
Yes

What Does The Subaru P1491 Code Mean?

With the engine started, the positive crankcase ventilation diagnosis voltage is High.

What Are The Symptoms Of The Subaru P1491 Code?

Improper idling

What Are The Potential Causes Of The Subaru P1491 Code?

  • Cracked or disconnected blow-by hose
  • Wiring harness between ECM and PCV hose assembly needs repair
  • Wiring harness between PCV hose assembly and ground chassis needs repair
  • Poor contact in ECM and PCV hose assembly connector
  • PCV hose assembly needs replacement

Recommended Parts

Below are some recommended auto parts to help you address the trouble code affecting your vehicle and get it running smoothly again:

>>> WORKPRO 582-piece Crimp Terminals, Wire Connectors, Heat Shrink Tube, Electrical Repair Kit
>>> Twippo 372Pcs Waterproof Wire Connectors Kit
>>> Genuine Subaru PCV Hose Kit for Turbo EJ - 11815AB711

Note: During the purchasing process, please check carefully whether the part you want to buy fits your car!

Reference Sources

2008 Impreza WRX Repair Manual for P1491 – Pages 276-277.

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