P226C Turbocharger boost is slow to respond to what the computer commanded

Turbocharger boost control "A" slow response

Severity not verified — if the car runs badly, have it inspected

Nissan treats P226C as a code with no drivability concerns in one bulletin, while owners report limp mode with it, so the severity depends on the symptoms.

It gets more serious if:

  • Inspect soon: Inspect soon if the truck or van loses power, drops into limp mode or hesitates hard when accelerating. Owners of Titan, ProMaster and Ram trucks describe power loss in traffic with this code, and Hino says low boost over a long time can damage the particulate filter.

Source: how we rate severity

P226C in short

P226C means the turbocharger did not reach the boost the computer asked for quickly enough. A software update, a leaking charge air cooler or hose, or a sticking turbo actuator or vane can be behind it. If power is normal it can wait; if it loses power or limps, get it checked soon.

On a turbocharged engine the computer commands a boost level and watches how fast the real boost follows. P226C is set when it follows too slowly, the 'A' boost control being the first control path.

Nissan's bulletin NTB16-095 for the 2016 Titan XD (Cummins diesel) pairs P226C with an exhaust pressure sensor code and fixes it with an engine computer reprogram when there are no drivability problems. FCA also lists P226C in broad PCM update bulletins for Ram heavy-duty trucks.

A ruptured charge air cooler can give low boost, according to Hino. Complaints for Ram and Nissan trucks describe a sticking or failing turbo actuator, so mechanical causes are possible when software is already current.

Most likely causes

  1. Engine computer software that needs an update

    Supported by vehicle data
    Why it ranks here
    Nissan NTB16-095 and several FCA PCM flash bulletins list P226C and fix it by reprogramming. Nissan limits its bulletin to trucks without drivability issues.
    What would change this
    Rises if the vehicle falls in a bulletin VIN range and the software is not current. Falls if the update is already installed or there are real power-loss symptoms.
    How to test the engine control module (ecm / pcm)

  2. Leaking or ruptured charge air cooler, hose or clamp

    Common general cause
    Why it ranks here
    Hino tells technicians to inspect the charge air cooler for ruptured tubes first when P226C or P0299 is stored with low power. Lost charge air makes boost slow to build.
    What would change this
    Rises if a boost leak test or visual check finds oil, a split tube or a loose clamp. Falls if the intake side holds pressure.

  3. Sticking or failing turbo actuator or vane

    Possible — needs testing
    Why it ranks here
    Owners of 2018 Ram 2500 and Nissan Titan trucks say the code points to the turbo or its actuator. These are owner statements, not a confirmed repair, so this ranks below the bulletin-backed causes.
    What would change this
    Rises if the actuator does not follow commands or P00AF is also stored. Falls if it moves smoothly and boost builds on a test.

  4. Exhaust restriction such as a plugged particulate filter

    Possible — needs testing
    Why it ranks here
    Hino bulletin TT-15-026 links a lit MIL and reduced power to an exhaust restriction such as a plugged DPF. It is a diesel-truck cause, so check it only on diesels.
    What would change this
    Rises if exhaust back pressure is high or particulate filter codes are stored. Falls if exhaust pressure is normal.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Scan for all codes and note P0299, P00AF, P0471 and filter codes. Ask a dealer whether a bulletin or software update applies to the VIN.

    Low riskTool: scan tool

  2. With the engine off, inspect the charge air cooler, its tubes and clamps for splits, oil residue or loose connections. A shop can pressure-test the intake.

    Use caution

    Warning:Hot charge air pipes and exhaust parts can burn; let the engine cool, and never run a pressure test above the manufacturer limit.

  3. Command the turbo actuator with a bidirectional scan tool and compare commanded and actual position and boost.

    Best left to a shopTool: bidirectional scan tool

    Warning:Moving the actuator with the engine running changes boost suddenly; keep clear of belts, fans and hot exhaust parts.

Symptoms

  • Check engine light on
  • Loss of power or limp mode Gets more serious: stop and have it checked.
  • Power returns after switching the engine off and on
  • Jerky acceleration as boost catches up

Compare with: Check engine light with loss of power

How to fix

Parts and cost context

  • Engine control module (ECM / PCM):A software flash is the first step where a bulletin applies; labor varies, get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Nissan

  • 2016 · Titan

    Supported by vehicle data

    Cummins diesel Titan XD: Nissan has a bulletin to reprogram the engine computer for P226C or P0471.

  • NTB16-095Status unverified

    MIL on with DTC P226C or P0471

    2016titan-xd · NHTSA 10109126

    Reprogram the engine computer when one or both codes are stored and there are no drivability issues. Summary read only.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Ram

  • 2019 · 2500

    Supported by vehicle data

    FCA lists P226C in a PCM update bulletin; an owner of a 2018 2500 reports limp mode with the code.

  • 18-010-21Status unverified

    PCM updates

    20192500, 3500 · NHTSA 10188801

    Reprogram the PCM; P226C is one of many listed DTCs. Summary read only.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • P0299Turbocharger or supercharger is producing less boost than the engine computer requested

    Shares causes Supported by vehicle data

    Hino and FCA bulletin summaries list P0299 and P226C together, and a low-boost problem can set both.

  • P0471Exhaust pressure sensor reading not making sense

    Shares causes Supported by vehicle data

    Nissan NTB16-095 lists P226C and P0471 together for the same reprogram.

All Turbocharging, fuel pressure and EGR codes

P226C questions

Can P226C be fixed with software?

Sometimes. Nissan and FCA both have bulletins that reprogram the computer for it, so ask a dealer to check the VIN before replacing the turbo.

Sources and review

  1. Nissan NTB16-095: 2016 Titan XD, MIL on with DTC P226C or P0471 — Nissan North America
  2. Hino SB-17-013: charge air cooler inspection, P0299 / P226C — Hino Motors
  3. NHTSA complaint ODI 11635736: 2016 Nissan Titan XD — NHTSA Office of Defects Investigation (public complaint)
  4. NHTSA complaint ODI 11442397: 2015 Ram ProMaster — NHTSA Office of Defects Investigation (public complaint)
  5. FCA bulletin 18-010-21: PCM updates (2019 Ram 2500/3500) — FCA US
  6. NHTSA complaint ODI 11697093: 2018 Ram 2500 — NHTSA Office of Defects Investigation (public complaint)
  7. NHTSA complaint ODI 11502807: 2017 Nissan Titan — NHTSA Office of Defects Investigation (public complaint)
  8. Hino TT-15-026: MIL and reduced power from exhaust restriction — Hino Motors
Last reviewed
Written by
Saurabh K.
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