What causes fault code P022A?

• Most likely: Faulty charge air cooler bypass solenoid (internal open circuit) • Likely: Damaged wiring or corrosion in the connector pins • Possible: Defective relay for the intake air system • Rare: Internal Engine Control Unit (ECU) failure

How do you fix fault code P022A?

STEP 1: Inspect the bypass solenoid connector for corrosion or backed-out pins. Clean as necessary. STEP 2: Measure the resistance (Ohm) of the bypass solenoid. Normal values are typically between 15-40 Ohms. An 'OL' (Infinite) reading indicates a failed solenoid. STEP 3: Check the wiring harness between the solenoid and the ECU. Check for continuity and ensure 12V supply is present. Use an oscilloscope to verify the PWM signal if necessary. STEP 4: Replace the charge air cooler bypass valve/solenoid if testing confirms a component failure. Clear codes and perform a test drive.

Powertrain (Engine & Gearbox)Standard EOBD

P022A - Charge Air Cooler Bypass Control Circuit Open

Q: What are the symptoms of fault code P022A?

• Check Engine Light (MIL) illuminated • Reduced engine performance (Limp mode) • Increased fuel consumption • Unusual noises from the intake path during acceleration • Issues with Diesel Particulate Filter (DPF) regeneration

Last updated:1 February 2026

Related:Charge Air Cooler Bypass Valve, ECU (Engine Control Unit), Wiring Harness, Solenoid Actuator

System

Powertrain (Engine & Gearbox)

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Technical Description

P022A is a generic OBD-II diagnostic trouble code indicating that the Engine Control Unit (ECU) has detected an open circuit in the Charge Air Cooler (CAC) bypass control valve circuit. In modern turbocharged engines, a bypass valve is used to divert intake air around the intercooler under certain conditions (e.g., cold starts or DPF regeneration). An 'Open' circuit status means there is a loss of electrical continuity, typically caused by broken wiring or a failed actuator solenoid.

Possible Causes

Faulty charge air cooler bypass solenoid (internal open circuit)

Damaged wiring or corrosion in the connector pins

Defective relay for the intake air system

Internal Engine Control Unit (ECU) failure

Symptoms

Check Engine Light (MIL) illuminated

Reduced engine performance (Limp mode)

Increased fuel consumption

Unusual noises from the intake path during acceleration

Issues with Diesel Particulate Filter (DPF) regeneration

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P022A - Charge Air Cooler Bypass Control Circuit Open

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P022A - Charge Air Cooler Bypass Control Circuit Open

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