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OBD-II Code

P1656

Severity

Not yet reviewed

Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.

Can you drive it

We cannot say

Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.

Indicative cost (USD)

$200–$1,800

From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.

P1656 on a Toyota is an Oil Control Valve (OCV) circuit fault on the exhaust-cam side of dual-VVT-i engines — same family of failure as P1349 but on the opposite camshaft.

How a shop works this

Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.

  1. Note every code that is set, not just this one.

    Codes that appear together usually narrow the cause faster than any one of them read alone.

  2. Read the freeze frame — the conditions the fault was recorded under.

    Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.

  3. Confirm the fault is current rather than history.

    Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.

  4. Then follow the diagnostic notes further down this page, in the order they are written.

    They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.

If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.

Common symptoms

  • Check engine light
Read the full diagnostic procedureP1656 on a Toyota is an Oil Control Valve (OCV) circuit fault on the exhaust-cam side of dual-VVT-i engines — same family of failure as P1349 but on…

P1656 on a Toyota is an Oil Control Valve (OCV) circuit fault on the exhaust-cam side of dual-VVT-i engines — same family of failure as P1349 but on the opposite camshaft. The ECM commands the exhaust OCV through a duty-cycle 0-100% PWM signal to advance or retard the exhaust cam, and watches the exhaust camshaft position sensor for the corresponding 0-50 degree phase response. P1656 specifically calls out an electrical or response fault on the OCV circuit — open, short to ground, short to power, or no mechanical response despite a valid command.

Cheapest-first ladder

  1. scan live data and check exhaust OCV duty-cycle commanded vs. actual cam angle (a healthy OCV should sweep smoothly through its full range during a back-probe test with the engine warm).
  2. Ohm-out the OCV at its 2-pin connector — most Toyota dual-VVT-i exhaust OCVs read 6.9-7.9 ohms across the solenoid.
  3. Check for 12V supply on the OCV power wire with the key on.
  4. Pull the OCV and inspect the strainer screen for sludge — same failure mode as the intake-side P1349.
  5. If electrical is clean and the screen is clean, the cam phaser itself may be worn (carbon-locked or worn-pin), which is a much more expensive fix involving cam-cover removal.
  6. Don't replace the exhaust OCV before checking the intake-side OCV too — on 2GR-FE and 2AR-FE engines, both OCVs share a common oil gallery and feed pressure, so a sludged intake-side strainer can starve the exhaust phaser of pressure and throw P1656 even when the exhaust OCV itself is fine.
Vehicle-specific patterns2007-2017 Camry / Avalon 3.5L (2GR-FE) and 2008-2020 Highlander / Sienna / RX350 throw P1656 from rear-bank exhaust OCV failure first because of exha…
  • 2007-2017Camry / Avalon 3.5L (2GR-FE) and 2008-2020 Highlander / Sienna / RX350 throw P1656 from rear-bank exhaust OCV failure first because of exhaust manifold heat soak — the rear bank is buried against the firewall and runs 30-50 F hotter than the front bank.
  • 2009-2017Camry 2.5L (2AR-FE) and RAV4 throws P1656 specifically after extended oil-change intervals because the strainer screen sludges and the exhaust phaser is the first to lose pressure under high RPM load.
  • 2010-2015Prius Gen3 (2ZR-FXE) Atkinson hybrid throws P1656 during cold EV-to-engine handoffs when oil pressure hasn't fully built — Toyota addressed some cases via ECM reflash.
  • 2008-2014Lexus IS-F (2UR-GSE 5.0L V8) and 2007-2017 LS460 (1UR-FSE) throws P1656 from a more expensive cam-phaser pin wear pattern that requires cam-cover-off repair.

Estimated repair$200 to $1,800.

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