DTC P0045 – Turbocharger/Supercharger Boost Control Solenoid “A” Circuit / Open.

✅ Meaning of Code P0045

P0045 indicates the Boost Control Solenoid “A” (also called turbo boost control valve / wastegate control solenoid) has an open circuit.
This means the ECM is not seeing electrical continuity—usually due to broken wire, loose connector, or failed solenoid.

✅ Common Affected Vehicles

👉🏻 Turbo diesel engines
👉🏻 Turbo petrol engines
👉🏻 Vehicles with electronically controlled wastegates

✅ Symptoms

Low boost / no boost

Poor acceleration

Turbo not engaging

Check engine light

Sometimes limp mode

✅ Causes

Electrical (Most Common)

1. Boost control solenoid connector loose or corroded

2. Broken wire / open circuit in harness

3. Faulty boost control solenoid (internal open coil)

4. Bad ground or fuse (if fused circuit)

5. ECM driver circuit fault (rare)
Mechanical (Less common)

Wastegate stuck open

Vacuum lines disconnected (in vacuum-operated turbos)

🔧 Step-by-Step Diagnosis (Workshop-Friendly)

1. Visual Inspection

Check solenoid connector for water, corrosion, damaged pins.

Inspect wiring harness from solenoid → ECM for cuts, rodent damage, or tension.

Check vacuum hoses (if vacuum type turbo).

2. Check Power Supply

Using a multimeter:

⭐ Ignition ON, probe the connector:

One pin should have 12V supply (sometimes 5V depending on vehicle design).
If no voltage → check fuse, relay, wiring.

3. Check Solenoid Coil Resistance

Remove the solenoid connector and measure resistance across the two pins.

Typical coil resistance: 20–40 ohms (varies by manufacturer)

If reading is:

OL / infinite → solenoid coil open → Replace solenoid

0 ohms → shorted → Replace solenoid

4. Check Continuity of Control Wire

Check continuity from solenoid signal wire → ECM pin.

If open, repair harness.

5. Command Solenoid Using Scanner

Using a scan tool with active test:

Run “Boost Control Solenoid Actuation Test”

Check if solenoid clicks/operates.
If no action:

Power present but no actuation → solenoid faulty

No power → wiring issue

Good power & wiring but no actuation → ECM driver fault (rare)

🛠 Fixes

⭐ Repair damaged wiring

⭐ Clean or replace solenoid connector

⭐ Replace faulty boost control solenoid

⭐ Repair vacuum hoses (if vacuum type)

⭐ ECM replacement (only after confirming driver failure)

📌 Extra Tip for Technicians

Many modern turbo systems use:

Electronic wastegate actuators

PWM boost control solenoids

If electronic actuator is used, P0045 may indicate:

Failed actuator motor

Faulty position sensor inside actuator

Scan for additional turbo actuator codes.

Welcome to madurai car service 💐🙏🏻.