Code
P0045
MITSUBISHI
P — Powertrain
Boost control solenoid
Views:
UK: 11
EN: 35
RU: 22
AI status
Completed
Completed
100%
Causes
- Open or short in solenoid wiring or connector
- Corroded or loose electrical connector at the solenoid
- Failed/blocked boost control solenoid (stuck open/closed)
- Leaking or disconnected vacuum/boost hoses to solenoid or actuator
- Faulty turbo actuator (mechanical binding or broken linkage)
- ECU driver circuit fault, blown fuse or relay affecting solenoid power
Symptoms
- Check Engine Light (MIL) illuminated with P0045 stored
- Reduced engine power or poor acceleration (limp/derate mode possible)
- Inconsistent or incorrect boost pressure (underboost or overboost)
- Hesitation, stalling, or rough idle in some cases
- Unusual turbo noises or repeated wastegate actuation
- Higher than normal exhaust smoke if boost uncontrolled
What to check
- Read freeze frame and active data with a scan tool; confirm P0045 and related codes
- Visually inspect solenoid, connector and harness for damage, corrosion, or loose pins
- Inspect vacuum/boost hoses for disconnection, kinks, cracks or blockages
- Measure solenoid coil resistance at ambient temperature and compare to spec
- Backprobe solenoid power/ground while cranking/running to confirm voltage and switching/PWM signal
- Use a smoke or pressure test to check for boost leaks and actuator hose integrity
Signal parameters
- Typical solenoid coil resistance: roughly 10–40 ohms at 20°C (manufacturer spec may vary)
- Supply voltage: battery voltage present at power terminal (0–14 V depending on key/run)
- Control signal: ECU usually switches ground or provides PWM duty from 0–100% to modulate boost
- Expected behavior: solenoid valve should click or change flow when energized; actuator position/boost pressure should respond to changing PWM or commanded values
Diagnostic algorithm
- Retrieve all stored and pending codes; note freeze frame and related turbo/boost codes.
- Perform a visual inspection of solenoid, harness and vacuum/boost hoses; repair any obvious damage.
- Check fuses/relays that feed the solenoid circuit; restore power if blown and retest.
- With connector disconnected, measure solenoid coil resistance and compare to spec. Replace solenoid if out of range or open/shorted.
- Reconnect and backprobe the power terminal with ignition on to confirm battery voltage; backprobe control terminal while cranking/running to verify switching/PWM using a multimeter or scope.
- Command the solenoid ON/OFF or vary duty via a capable scan tool and confirm a physical response (click) and change in actuator movement or boost pressure.
- Inspect and pressure/smoke test vacuum/boost hoses and actuator for leaks or binding; repair or replace as needed.
- If wiring and solenoid check good but no control signal, test ECU driver output and check for short-to-ground; consult vehicle wiring diagram and replace ECU only after all other faults excluded.
- Clear codes and perform a road test to verify proper boost response and that the code does not return.
Likely causes
- solenoid coil open or shorted
- contaminated or stuck valve inside solenoid
- disconnected or crushed vacuum/boost hose
- intermittent connector pin or corrosion
- ECU output transistor failure or blown fuse
Fault status
Status
P0045 is set when the engine control module detects a fault in the boost control solenoid circuit or function. This can be caused by wiring, a failed solenoid, hose leaks, or ECU output problems and may lead to incorrect boost control and reduced engine performance.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
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