Diesel Trouble Codes

P0045 — Turbocharger Boost Control Solenoid A Circuit/Open (LLY / LBZ / LMM Duramax)

Diagnostic reference for LLY/LBZ/LMM Duramax 2004.5–2010. P0045 indicates the PCM has detected an electrical fault in the turbocharger boost control solenoid A…

Updated September 2, 2026

What it means

The powertrain control module has detected an electrical fault in the turbocharger boost control solenoid A circuit. On LLY/LBZ/LMM Duramax, the turbo is variable-geometry with electric servo actuation and position feedback. P0045 is a valid VGT boost control code for this platform.12

Most likely causes

  1. Open or short in the boost control solenoid A wiring harness or connector, leading to circuit/open detection by the PCM. — Inspect harness routing near hot turbo and engine movement for chafing, heat damage, or connector corrosion. Check for backed-out pins at the solenoid and PCM connectors. Verify reference/ground integrity for the solenoid driver circuit.1
  2. Failed turbocharger boost control solenoid A (electrical coil open/short). — A solenoid with an open coil or internal short will set a circuit/open fault. Electrical testing of solenoid resistance and isolation from ground can be performed; replace solenoid if electrical values are out of specification.1
  3. PCM driver fault for the boost control solenoid A circuit. — If wiring and solenoid test good, the PCM internal driver may be unable to command the solenoid. Confirm power/ground supplies to PCM and compare with known-good data before condemning PCM.1

How to diagnose

  1. Verify code P0045 is present and review freeze frame for engine conditions at set.
  2. Visually inspect turbocharger boost control solenoid A connector and wiring for heat damage, oil contamination, and secure latch.
  3. Check wiring continuity and isolation to ground and battery voltage between solenoid connector and PCM harness; look for opens or shorts.
  4. Measure solenoid coil resistance per service information and compare to specification; check for short to ground or power.
  5. Inspect related VGT system components for signs of damage that could affect wiring, e.g., turbo heat shield condition and nearby harness clips.
  6. If electrical tests pass, verify PCM powers/grounds and scan for additional VGT codes such as P003A, P2563, P2564 that may indicate broader VGT control issues.
  7. Clear codes, perform a controlled engine run and rescan to confirm fault returns.
  8. Document findings and advise repair of identified electrical fault before returning vehicle to service.

Parts and tools you may need

Rough cost and difficulty

Parts and labor vary by region and shop. Electrical diagnosis time is typically 1–2 hours; solenoid replacement adds parts and labor. PCM replacement, if required, is higher cost and should be confirmed by testing.

When to see a pro

If wiring tests are inconclusive, or PCM driver fault is suspected, have a qualified diesel technician perform pinpoint electrical tests and, if needed, PCM evaluation. Do not attempt high-pressure fuel or turbocharger mechanical service without proper training and equipment.

Sources

  1. Curated DTC seed — LLY / LBZ / LMM Duramax (curated) ↩︎ ↩︎ ↩︎ ↩︎

  2. Curated DTC seed — LLY / LBZ / LMM Duramax (curated) ↩︎