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P2677 — Air Cleaner Inlet Control Circuit High

Manufacturer-specificPowertrain (engine & transmission)

P2677 indicates the powertrain control module (PCM) has detected a high voltage condition in the air cleaner inlet control circuit. This circuit controls an actuator or motor that manages airflow into the engine, often for cold-air intake or variable intake systems. The code means the component is stuck in one position or there's excessive voltage in the circuit.

Symptoms

What causes it — most likely first

1. Failed air cleaner inlet control motor/actuator

The electric motor or actuator that opens/closes the air intake door has failed internally, causing an open circuit or mechanical seizure that reports high voltage to the PCM.

2. Wiring short or harness damage

The wiring harness to the inlet control motor has a short to battery power, chafed wires, or damaged insulation causing an artificially high voltage signal.

3. Corroded or loose electrical connector

The connector at the inlet control motor has corrosion, bent pins, or poor contacts that create high resistance and voltage irregularities.

4. Blown fuse or faulty relay

A blown fuse or stuck relay in the control circuit causes voltage irregularities that trigger the high circuit code.

5. Vacuum-operated system leak or failure (if applicable)

For vacuum-controlled intake systems, a leak, disconnected hose, or failed vacuum actuator can cause the position sensor to report an abnormal reading.

6. PCM/ECM fault (least likely)

Rarely, the PCM itself may misinterpret sensor signals or have internal circuit failures, but this should only be considered after all other causes are ruled out.

How it's diagnosed

  1. Connect an OBD-II scanner and verify P2677 along with any other stored codes; note freeze frame data for driving conditions.
  2. Perform a visual inspection of the air cleaner housing, inlet door, and all wiring for damage, corrosion, or disconnected connectors.
  3. Check the fuse and relay that power the inlet control circuit; replace any that are blown or suspected of being faulty.
  4. Test voltage and ground at the inlet control motor connector with a multimeter while commanding the actuator to operate (if scan tool bi-directional control is available).
  5. Inspect vacuum hoses (if equipped) for cracks, disconnections, or leaks that could affect intake door position.
  6. If the motor/actuator does not respond to commands and all wiring checks pass, the inlet control motor assembly is likely failed and requires replacement.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)
Related codesP2670 — Actuator Supply Voltage B Circuit LowP2671 — Actuator Supply Voltage B Circuit HighP2672 — Injection Pump Timing OffsetP2673 — Injection Pump Timing Calibration Not P2674 — Injection Pump Fuel Calibration Not LeP2675 — Air Cleaner Inlet Control Circuitopen

Frequently asked

Can I drive with a P2677 code?

You can typically drive short distances, but reduced engine performance and potential stalling may occur. The issue should be diagnosed and repaired promptly to prevent further drivability problems.

Will replacing the air filter fix this code?

No. A clogged air filter does not cause a P2677 code. This code indicates an electrical circuit issue with the inlet control mechanism, not an airflow restriction.

Do I need to replace the PCM for P2677?

Almost never. The PCM is the least likely cause of this code. Reputable shops will rule out all other causes (motor, wiring, connectors, fuses) before considering PCM replacement. Be wary of anyone who immediately suggests replacing the computer for this code.

How much does repair cost?

Costs vary by vehicle make and model. The inlet control motor assembly itself typically ranges from $50 to $300, plus labor. Wiring repairs are usually less expensive if only a connector or fuse is involved.