P2390

Code

Generic P — Powertrain

Diesel Intake Air Flow B Control Circuit/Open

Brand: Generic

Type: P — Powertrain

Views: UK: 20 EN: 29 RU: 26

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Page language: EN

Causes

Open or damaged wiring harness to intake air flow B actuator/sensor
Corroded, bent or disconnected connector/pins at actuator or PCM
Failed intake air flow B actuator, sensor or control solenoid
Poor or missing ground or supply voltage
Faulty PCM (less common) or internal driver failure
Intermittent connection due to heat, vibration, or contamination

Symptoms

Check Engine MIL illuminated
Reduced engine power or limp-home mode
Poor idle, rough running or surging
Reduced turbo response or increased turbo lag (diesel)
Reduced fuel economy

What to check

Read and record freeze frame and all stored DTCs with a scan tool; clear and retest to confirm repeatability
Visual inspection of harness, connectors and actuator for damage, corrosion, water intrusion or loose pins
Backprobe connector with ignition on to verify supply voltage and ground presence
Check continuity and resistance between actuator connector and PCM connector (check for opens/shorts)
Command the actuator with a bidirectional scan tool (if available) and observe response
Measure actuator coil resistance against specification or bench-test actuator operation

Signal parameters

Supply voltage: approximately battery voltage with ignition ON (verify vehicle-specific)
Control signal: typically PCM-driven PWM or switched DC — duty cycle varies with commanded air flow
Expected idle/rest signal: may be near 0 V or battery voltage depending on circuit design
Actuator/solenoid resistance: typically low (single- to low-double-digit ohms) for solenoids; consult vehicle spec
Open-circuit symptom: infinite resistance/OL between actuator and PCM or no change when commanded

Diagnostic algorithm

Use a scan tool to confirm P2390 and note freeze frame and any related codes (boost, MAF, cam/crank).
Perform a visual inspection of connectors, wiring and the actuator. Repair obvious damage before further testing.
With ignition ON (engine OFF), backprobe the actuator connector: verify battery supply, ground, and control signal presence while commanding the actuator from a scan tool.
Measure resistance of the actuator/solenoid. If open or out of spec, replace the actuator.
Check continuity between the actuator connector and the PCM connector for opens or shorts to ground/12V. Repair wiring faults as needed.
If wiring and actuator check OK, verify PCM driver operation by observing control signal under commanded conditions. If driver is not switching and wiring is good, consider PCM fault and consult manufacturer guidance.
After repairs, clear codes and perform road test to confirm the fault does not return.

Likely causes

Broken/disconnected connector at intake air flow B actuator
Wiring harness chafed or shorted between actuator and PCM
Failed actuator/solenoid on intake air flow B
Corroded pin or poor ground at connector

Fault status

⚠️ Status

P2390 - Diesel Intake Air Flow B Control Circuit/Open: Open or fault detected in intake air flow B control circuit. Check actuator/solenoid, wiring, connectors and PCM driver.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours