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DTC codes / Mercedes-Benz codes / P1622

P1622 · Mercedes-BenzElectrohydraulic Shut-Off Actuator Y11

P1622 on Mercedes-Benz vehicles indicates that the engine control module (ECM) has detected an electrical fault in the circuit for the electrohydraulic shut-off actuator Y11, which is used on certain diesel engines to cut fuel delivery for a safe shutdown. The ECM monitors the actuator's coil for expected resistance and current draw, and it sets this code when the signal is out of range, open, or shorted.

SystemPowertrain
Code typeMercedes-Benz specific
SeverityMedium
Fix difficultyIntermediate
AreaComputer and output circuits

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms.
  • Engine may crank but fail to start or stall immediately after starting.
  • Rough running or misfire under load if the actuator fails to close fully.
  • Reduced engine power or limp mode in some driving conditions.
  • A noticeable click or lack of click from the actuator area when the ignition is turned on.
  • In rare cases, the engine may not shut off immediately when the key is turned off.

Common causes, most likely first

  1. Failed electrohydraulic shut-off actuator Y11 (open or shorted internal coil).
  2. Damaged or corroded wiring harness connector at the actuator.
  3. Broken, chafed, or shorted wires between the actuator and the ECM.
  4. Poor ground connection for the actuator circuit.
  5. Faulty engine control module (ECM) driver circuit, though this is less common.
  6. Oil or coolant contamination at the actuator connector causing signal interference.

How to diagnose and fix it

  1. Verify the code with a Mercedes-Benz-specific scan tool and check for any related fault codes in the ECM.
  2. Inspect the actuator connector and wiring for corrosion, loose pins, or physical damage; clean or repair as needed.
  3. Measure the resistance of the Y11 actuator coil with a multimeter and compare to the manufacturer's specification.
  4. Check for continuity and short-to-ground or short-to-power on the wires between the actuator and the ECM.
  5. Test the actuator by applying 12 volts momentarily to confirm it clicks and moves freely; replace if it does not.
  6. If wiring and actuator test good, check the ECM driver circuit with an oscilloscope or by substitution with a known-good unit.
  7. Clear the code and perform a road test to confirm the repair, ensuring the actuator operates correctly during engine shutdown.

Before you replace the Y11 actuator

  • A common mistake is replacing the actuator when the real problem is a corroded connector pin or a chafed wire near the engine block, so always perform a resistance and wiggle test first.
  • The Y11 actuator is often confused with the intake manifold flap actuator or the EGR valve actuator on Mercedes diesel engines, so confirm the component location using the wiring diagram for the specific model.
  • This code can be set intermittently by a weak battery or poor charging system, as low voltage can cause the ECM to misread the actuator current draw.
  • On some models, the actuator is part of the high-pressure fuel pump and cannot be replaced separately, requiring pump replacement if the coil fails.
  • A failed actuator may not always trigger a noticeable drivability symptom, so do not assume the code is false just because the engine runs fine.

Can I keep driving with P1622?

If the engine starts and runs normally, you can drive the vehicle to a workshop for diagnosis, but avoid long trips or heavy loads. If the engine stalls, fails to start, or does not shut off with the key, stop driving and have the vehicle towed to prevent safety risks.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Mercedes-Benz vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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