P0750 Code: Subaru Impreza (2017-2023) - Causes, Symptoms & Fixes

No recalls found in NHTSA database

No official NHTSA complaints were found for Subaru Impreza (2017–2023) with code P0750 in the provided data. This guide uses general OBD-II knowledge and Subaru-specific transmission considerations, but the data limitations mean you won’t see manufacturer or safety-relation context here. Use this as a diagnostic framework in addition to Subaru service information and your vehicle’s specific repair manual.

1. CODE MEANING AND SEVERITY

• Code meaning: P0750 is commonly defined as a Shift Solenoid A Malfunction (or Shift Solenoid A Circuit Malfunction) in many OBD-II and manufacturer defect lists. In a CVT-equipped Subaru Impreza, it generally points to a fault in the circuit that controls Solenoid A within the transmission valve body, or a fault in the solenoid itself.
• Severity and symptoms: This is a transmission control issue. If the PCM/TCM detects a fault in the Shift Solenoid A circuit, you may experience one or more of the following:
  • Erratic or delayed upshifts or downshifts
  • Harsh or slushy shifting
  • Transmission may go into a limp/limited mode to protect itself
  • Check Engine Light (CEL) and a stored P0750 DTC
  • Possible downshift or upshift failure, getting stuck in a single gear (often in safer, limp-like operation)
  • Transmission life could be impacted if driving with an intermittent or unresolved fault
• Important note: On Subaru Impreza CVT models, solenoids and the valve body control CVT operation. A P0750 may be caused by electrical issues in the wiring or a faulty solenoid rather than a purely mechanical valve body problem. Always verify with trans-specific diagnostic steps.

2. COMMON CAUSES ON SUBARU IMPREZA

• Faulty Shift Solenoid A (SOL A) or Solenoid A coil failure
• Wiring harness damage, loose/ corroded connectors, or poor grounds to the solenoid or TCM
• Faulty or corroded transmission control module (TCM) wiring or poor TCM communication
• Low, dirty, or degraded CVT fluid (Subaru CVT Fluid) or incorrect fluid type
• Contaminants or sludge in the valve body affecting solenoid operation
• Valve body wear or sticking valves affecting hydraulic pressure
• Electrical fuses or fusible links related to the TCM/solenoid circuits
• Temperature-related issues (solenoid performance can degrade when hot)
• In some cases, software/learned behavior in the TCM can trigger a P0750 until re-learned or updated

3. SYMPTOMS

• Transmission warning light or CEL illuminated
• Delayed engagement, hesitating or abrupt shifts
• Harsh or rough shifting between gears or gear ranges
• Frequent or intermittent upshift/downshift problems
• Transmission goes into “limp” mode or reduced power mode
• No noticeable engagement into a certain gear, or gear hunting
• Noise or clunking during shifts (less common but possible with valve-body issues)
• If CVT fluid is degraded, you may notice burning smell, dark or burnt fluid color, or coolant-like metallic taste in the fluid sample (rare but possible)
• Some drivers may not notice until under load or temperature changes

4. DIAGNOSTIC STEPS
   Important: Use the vehicle’s factory service information and a capable scan tool that can access transmission data (TCM data, solenoid duty cycles, and live sensor data). Steps assume CVT-equipped Subaru Impreza (2017–2023).

• Step 0: Confirm the DTC

  • Retrieve all DTCs (P0750 and any related P07xx/TCM codes). Note freeze-frame data, voltage readings, and any live data during a test drive.

• Step 1: Visual and connectors

  • Inspect the shift solenoid A connector and wiring harness for damage, corrosion, and secure locking latch.
  • Check for damaged pins, bent terminals, or signs of water ingress.
  • Inspect the transmission valve body area for signs of leaks or contamination.

• Step 2: Check transmission fluid and condition

  • Check CVT fluid level when the car is at proper temperature (hot-level check per service manual).
  • Look at CVT fluid color and odor. A burnt or very dark fluid indicates degradation or overheating; replace if needed.
  • Confirm correct CVT fluid type (Subaru JF010 or OEM-recommended) and ensure no incorrect fluid mixed in.

• Step 3: Electrical checks

  • Check fuses and relays associated with the TCM and transmission circuits.
  • With the engine off, test for continuity and resistance in the SOL A circuit from the TCM connector to the solenoid. Compare to manufacturers’ spec (the service manual will list expected resistance and voltage supply checks).
  • With the engine running, check for proper power supply to SOL A, ground continuity, and signal from the TCM. Look for voltage drop or intermittent grounding.
  • Check for PCM/TCM communication issues that could falsely trigger P0750 (look for other DTCs that indicate communication faults).

• Step 4: Solenoid and valve body testing

  • Replace Shift Solenoid A if resistance and signal are out of spec, or if there is an open/short in the circuit after wiring checks are clean.
  • If the solenoid tests within spec, suspect the valve body or hydraulic circuit. Sticking or binding of solenoids/valves can cause improper hydraulics and trigger P0750.
  • In some cases, a solenoid bank re-test or a valve body cleaning/replace may be necessary.

• Step 5: Transmission data stream and function tests

  • Use a diagnostic tool to view solenoid duty cycle and current (if tool supports this). Compare to Subaru service data.
  • Perform a road test while logging data to observe shifting behavior, duty cycles, and any abnormal data patterns when the fault occurs.
  • If the issue is intermittent, consider a temporary service solution (e.g., solenoid cleaning and fluid change) to determine if behavior changes.

• Step 6: Clean-up logic and recheck

  • Clear DTCs (if you confirm the fault is resolved) and monitor for reoccurrence. If P0750 reappears within a short period, more invasive action (solenoid replacement, valve body service, or valve body replacement) may be needed.

• Step 7: If all electrical checks pass, consider mechanical causes

  • Valve body wear, internal leakage, or hydraulic pressure problems that solenoids alone cannot fix
  • CVT clutch wear or internal CVT issues can mimic shift solenoid faults and may require more extensive transmission service

5. RELATED CODES

• P0700 – Transmission Control System Malfunction (generic umbrella code often set with shift/solenoid issues)
• P0770–P077x family (Shift Solenoid B and related circuits) can appear in some cases if multiple solenoid circuits are involved
• P0740 – Torque Converter Clutch Circuit Malfunction (occasionally observed with transmission control faults)
  Note: Specific Subaru Impreza wiring and solenoid configurations can differ between 2017 and 2023 models, and between CVT-equipped trims. Use your OEM service information for exact cross-codes and wiring diagrams.

6. REPAIR OPTIONS AND COSTS (2025 PRICES)
   Important: These are typical ranges. Actual costs depend on region, shop rates, and the exact CVT configuration (some Impreza trims use a CVT with a dedicated valve body assembly).

• Do-it-yourself solenoid replacement and fluid change

  • Parts: Shift Solenoid A (and associated connectors if needed) plus CVT fluid
  • Estimated parts: $50–$200
  • Estimated labor (if you do basic unplug/plug and simple replacement): $0–$150 (if you’re doing it yourself) or more if you hire a shop for a quick solenoid swap only
  • Fluids and incidental costs: $40–$100
  • Total DIY range: $90–$300 (tooling not included; if you need a special solenoid tool or more extensive disassembly, costs go up)

• Professional shift solenoid A replacement (solenoid only, with fluid change)

  • Parts: Shift Solenoid A, gaskets/seals as needed
  • Labor: 1.0–2.5 hours depending on access
  • Estimated total: $300–$900

• Valve body service or replacement (more thorough)

  • Parts: Valve body kit or replacement unit
  • Labor: 3.0–6.0 hours
  • Estimated total: $1,000–$2,500 (parts + labor)
  • Note: If the valve body is contaminated or damaged, this is a common follow-up step if solenoid replacement alone doesn’t fix P0750

• Transmission fluid service (CVT fluid change, filter if applicable)

  • Parts: CVT fluid, filter (if serviceable)
  • Labor: 0.5–1.5 hours
  • Estimated total: $150–$400

• Transmission overhaul or replacement (rare but possible)

  • Parts: New or rebuilt transmission or substantial internal components
  • Labor: 6.0–12.0 hours
  • Estimated total: $3,000–$6,500+ (depending on whether a full remanufactured unit is used and regional labor rates)

• Miscellaneous

  • Electrical harness repair, connector replacements, fuses, or TCM reflash/updated calibration (if required by a service bulletin or dealer update)
  • Costs vary; electronics work can add several hundred dollars

7. DIY vs PROFESSIONAL

• DIY viability:
  • Easy to moderate for straightforward solenoid replacement and fluid drain/refill if you have basic tools and a service manual.
  • CVT work is often more involved; access to the solenoids can be challenging and requires careful handling of valve bodies and transmission housings.
  • You will need a capable OBD-II/TCM scan tool and possibly Subaru-specific software to capture live data, solenoid duty cycles, and to perform any re-learn procedures after service.
• Professional advice:
  • If you don’t have experience with CVT transmissions and solenoids, or if the diagnosis relies on valve body condition or torque-converter or mechanical transmission issues, a transmission specialist is recommended.
  • CVTs can be sensitive to fluid type and exact procedures; incorrect fluid or improper fluid levels can cause further damage.

8. PREVENTION

• Use the correct Subaru CVT fluid (and the correct spec for your model year; Subaru CVTF is typically specified by Subaru for CVT gearboxes)
• Change CVT fluid at intervals recommended by Subaru for your model year/trim (noted in the owner’s manual or service schedule)
• Inspect and replace the transmission fluid filter if serviceable; ensure the system is properly drained and refilled
• Keep the cooling system for the transmission in good condition; overheating CVTs increases wear on solenoids and valve body
• Avoid aggressive driving patterns that can cause rapid heating and high line pressure
• Address transmission warning lights promptly to prevent minor issues from becoming major repairs
• Ensure electrical connections to the TCM/solenoids are clean, tight, and free of corrosion
• If you notice fluid leaks, get them addressed promptly to prevent low fluid levels that can trigger solenoid faults

DATA LIMITATIONS

• The provided data states “No recalls found in NHTSA database” for this make/model/year and issue, and there are “No NHTSA complaints found.” This means you should not rely on official complaints/recalls for guidance here; treat this as a general diagnostic framework rather than a model-year-specific, NHTSA-confirmed issue.