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P codepowertrainMedium severity

P0027Exhaust Valve Control Solenoid Circuit Range/Performance (Bank 1)

The Bank 1 exhaust valve control solenoid circuit is working, but its measured behavior is outside the expected range.

Definition

The PCM monitors the Bank 1 exhaust valve control solenoid circuit and the exhaust cam/valve response it produces on engines with variable exhaust valve timing or lift. P0027 sets when circuit values or system response fall outside the calibrated range without being a hard open or short. Expect an illuminated MIL with possible rough idle, reduced power, poor fuel economy, and in some cases increased emissions that can fail an inspection.

Common causes

  • Low, dirty, or incorrect-viscosity engine oil impairing solenoid and actuator response
  • Sticking or debris-contaminated exhaust valve control solenoid on Bank 1
  • Clogged solenoid filter screen or oil gallery
  • High resistance or intermittent wiring/connector faults in the solenoid circuit
  • Solenoid winding resistance drifted out of specification
  • Worn exhaust cam phaser/actuator not responding to commanded oil flow

Common misdiagnoses

  • Replacing the solenoid before addressing oil level, viscosity, or sludge
  • Replacing the exhaust camshaft position sensor when the actuator circuit is the fault
  • Replacing the cam phaser when a clogged solenoid screen is the actual restriction
  • Condemning the PCM for a harness connector problem

Troubleshooting steps

  1. 1.Check oil level and quality

    Top off or change the oil to the specified viscosity first, because marginal oil supply is the leading cause of valve control range/performance codes.

  2. 2.Test solenoid resistance and grounds

    Measure the Bank 1 exhaust solenoid winding against the service spec and confirm it is not shorted to ground or battery voltage.

  3. 3.Inspect the circuit wiring

    Wiggle-test the harness between the solenoid and PCM while monitoring live data, looking for intermittent resistance changes at connectors.

  4. 4.Actuate the solenoid with a scan tool

    Command the exhaust valve control solenoid and confirm the cam position or valve response PID follows the command promptly.

  5. 5.Remove and clean/inspect the solenoid

    Check the pintle for free movement and the screen for sludge or metal debris; replace the solenoid if it sticks after cleaning.

  6. 6.Verify actuator response after repair

    Clear the code, run the engine to full operating temperature, and confirm commanded versus actual exhaust valve position track together.

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