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Engine

Boost leaks, low boost and P0244 wastegate solenoid code

The stock top-mount intercooler separates at its passenger-side end tank, the turbo inlet hose tears at the clamp, and the small vacuum lines and restrictor pill for the wastegate crack or go missing. The result is low boost, a stumble around 3,000 rpm, lean fueling, and sometimes P0244 with fuel cut above 4,000 rpm.

CommonSeverity: MajorApplicability: Direct

Frequency basis: Three separate 2005 XT/GT threads (one 114 replies) plus the known-issues compendium naming the intercooler end tanks. Boost leaks are the usual cause of lean codes, stumbling and limp mode on these cars, and lean running is what hurts the engine.

Symptoms

  • Boost of only 6–9 psi where a healthy stock car makes 10–12 psi; stumble between off-boost and on-boost around 3,000 rpm
  • Lean at idle and rich on boost on a wideband; misfire codes; high learned timing pulls
  • P0244 with the car in limp mode (wastegate duty 0%) and fuel cut at high rpm
  • Oil leaking from the dipstick tube or filler when the intake is pressure-tested (stuck PCV pushing boost into the crankcase)

Causes found

  • Cracked or separated intercooler end tank (21821AA021)
  • Torn turbo inlet hose (14447AA120), usually at the clamp
  • Wrong or missing vacuum tee and restrictor pill in the wastegate lines; torn wastegate or compressor line (a tear causes overboost, a missing pill causes underboost)
  • Broken nipple on the evap purge valve; split bypass valve or intercooler gaskets
  • Faulty boost control solenoid (16102AA340), or a MAP sensor reading out of range
  • Stuck-open PCV valve

Check in this order

  • Smoke-test or pressure-test the intake from the turbo inlet at about 1 psi (smoke) or up to 15–20 psi (pressure, with a DIY PVC tester); never with the oil cap on if the PCV is suspect
  • Move the wastegate arm by hand (stiff but free); trace all four small lines and confirm the restrictor pill
  • Check boost solenoid resistance and swap with a known-good unit
  • Log boost, AFR and knock with BtSsm or an AccessPort before and after repairs; do not reset the ECU, which hides the knock learning

What fixed it

  • New turbo inlet hose, purge valve and cracked hoses cured the stumble on one 2005 XT after two shops missed it
  • Correct vacuum tee and restrictor pill raised boost from 6 to 8–9 psi on a 5MT XT
  • Reinforce the intercooler end-tank tabs or fit an aftermarket intercooler; replace the stock unit if it is split
  • Used boost control solenoids found for under $20 when the solenoid tests bad

References on this site

OEM parts

  • 21821AA021Intercooler
  • 14447AA120Hose assembly, turbocharger inlet
  • 16102AA340Valve assembly, duty solenoid (boost control)
  • 14471AA130Boost pressure control (bypass) valve
  • 22012AA210Manifold absolute pressure sensor
  • 42084FE010Valve, purge

Maintenance guides

Sources

Forum threads are owner reports, not factory findings. Counts are from the threads and complaint records read for this page; read the sources before buying parts.

  1. 1.
    My first Subaru! New-to-me 2005 XT 5EAT stumbling and P0244

    subaruoutback.org · Forum thread · 2018, 114 replies, torn inlet hose found by smoke test

  2. 2.
    Low boost issues 2005 Outback xt

    subaruoutback.org · Forum thread · 2018, 2005 XT 5MT at 130k, restrictor pill and PCV

  3. 3.
    Code P0244 (Possible intercooler problem?)

    legacygt.com · Forum thread · 2016, wastegate line checklist from a 2005 XT owner

  4. 4.
    2005 Outback XT Surging Under Constant Load

    subaruoutback.org · Forum thread

  5. 5.
    Known Issues with 2005 Outback XT Limited???

    subaruoutback.org · Forum thread · intercooler end tanks separate and cause a vacuum leak