P0045

Code

ISUZU P — Powertrain

Turbocharger Boost Control Solenoid Circuit

Brand: ISUZU

Type: P — Powertrain

Views: UK: 8 EN: 19 RU: 22

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Page language: EN

Causes

Open or shorted wiring to the boost control solenoid
Corroded/damaged connector or poor pin contact
Failed boost control solenoid valve (electrical or mechanical)
Faulty ground or fused power feed to the solenoid
Intermittent wiring damage (chafing, rodent bite)
Faulty PCM (rare)

Symptoms

Check Engine Light (MIL) illuminated
Reduced engine power or limp mode due to limited boost
Poor acceleration and slower spool-up
Inconsistent or no turbo boost; boost gauge low or erratic
Black smoke on heavy load (diesel) or excessive exhaust soot
Stored freeze frame or related boost codes

What to check

Read stored DTCs and freeze-frame data with a scan tool
Check live data: commanded duty cycle and actual boost pressure/MAP
Visual inspection of solenoid, connector, and wiring for damage or corrosion
Wiggle test wiring while monitoring PID/voltage for intermittent faults
Check fuses and power/ground at the solenoid connector with key ON
Measure coil resistance of solenoid (compare to spec)

Signal parameters

Control: PWM duty cycle 0–100% (ECM varies command based on load)
Typical supply: vehicle battery ~12 V present on power feed (key ON)
Coil resistance: commonly 10–40 ohms (model-dependent; check OEM spec)
PWM frequency: commonly tens to a few hundred Hz (varies by vehicle)
Expected behavior: commanded duty changes with throttle/load and actual boost responds correspondingly

Diagnostic algorithm

Use a scan tool: record P0045, related codes, freeze-frame and live PIDs (commanded duty, MAP/boost).
Perform visual inspection: connector condition, pins, wiring harness route, fuses and grounds. Repair visible damage.
With key ON, verify battery power at the solenoid power pin and a good ground. If no power, trace fuse/relay/ignition feed.
Measure solenoid coil resistance at the connector (unplugged). Compare to OEM spec; an open or near-zero short indicates a failed solenoid.
Backprobe the control pin while commanding the solenoid ON/OFF with a scan tool and observe voltage/PWM and duty change. Look for proper switching between ~0–12 V or PWM signal.
Wiggle test wiring and connectors while watching live data for intermittent faults. Repair any faults found.
Bench test solenoid if removed: apply 12 V to power/ground and verify audible click and flow change; apply vacuum/pressure and confirm valve operation if applicable.
Inspect vacuum/pressure hoses and wastegate actuator for leaks or mechanical binding; repair as needed.
If wiring and solenoid test good, check PCM outputs and grounds. If suspect PCM after eliminating wiring/solenoid, consult manufacturer procedures before replacement.
Clear codes and perform road test while monitoring commanded duty and boost behavior to confirm repair.

Likely causes

Damaged connector at the solenoid (corrosion, bent pins)
Broken/shorted harness between solenoid and ECM
Failed solenoid coil (open or short)
Blown fuse or missing constant/key power to solenoid
Pinched or disconnected vacuum/pressure hose causing solenoid to be driven hard

Fault status

⚠️ Status

Turbocharger Boost Control Solenoid Circuit — ECM detected an electrical fault in the boost control solenoid circuit (open/short/intermittent). Inspect wiring, connector, fuse/power, ground, and the solenoid valve.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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P0045 — Turbocharger Boost Control Solenoid Circuit