P0335 Code: Subaru Impreza (2017-2023) - Causes, Symptoms & Fixes

No recalls found in NHTSA database

No NHTSA complaints were found for this specific make/model/year/issue combination, and there are no recalls listed for P0335 on a 2017–2023 Subaru Impreza in the provided data. The diagnostic guide below uses general automotive knowledge for the crankshaft position sensor circuit in the context of the Subaru Impreza, with explicit note of the data limitations.

CODE MEANING AND SEVERITY

• Code: P0335
• Description: Crankshaft Position Sensor “A” Circuit Malfunction
• What it means: The engine control module (ECM/PCM) is not seeing a valid crankshaft position signal from the crankshaft position sensor (CKP) on the A circuit. Without a valid CKP signal, the engine cannot reliably control ignition timing and fuel injection, which can lead to no-start, stalling, misfires, or reduced power.
• Severity: Moderate to high. A persistent P0335 can immobilize the vehicle or cause poor drivability and possible engine damage if the timing is not properly controlled and the engine is operated.

COMMON CAUSES ON SUBARU IMPREZA

• Faulty crankshaft position sensor (CKP) itself
• Damaged, frayed, or corroded CKP wiring harness or connector (including pin corrosion, bent pins, water intrusion)
• Poor or intermittent electrical connection between CKP and the PCM
• Faulty power supply or reference to the CKP circuit (fuse, relay, or PCM bias)
• Timing-related issues (timing belt/chain wear or misalignment, or a sensor mounting issue relative to the reluctor/wheel)
• Damaged reluctor wheel or missed teeth on the crankshaft gear (less common but possible)
• PCM/ECU fault (less common; typically a symptom after wiring or sensor issues)

SYMPTOMS

• Engine cranks but does not start (no-fire condition)
• Engine loses spark/fuel control and stalls, or stalls while running
• Intermittent no-start or hard-start conditions
• Rough idle or misfires when the engine does start
• Reduced engine power or limp mode in some cases
• Check Engine Light (CEL) with P0335 stored or pending
• May be accompanied by other CKP-related codes (P0330, P0336, P0337, P0338) depending on the test results and the vehicle’s behavior

DIAGNOSTIC STEPS

Note: Work methodically and verify vehicle-specific wiring diagrams when available. (No recalls/TSBs cited from the data; use general diagnostic best practices.)

A. Initial verification

• Retrieve DTCs with a scan tool and note freeze-frame data (engine RPM, load, temps, etc. during the fault).
• Check for related codes (P0330, P0336, P0337, P0338, P0339, etc.) that can indicate circuit issues or related sensor problems.
• Inspect for obvious mechanical issues (timing belt/chain condition if accessible, recent timing work, or engine mechanical problems).

B. Visual and electrical inspection

• Inspect CKP sensor and its wiring harness for damage, abrasion, oil contamination, or loose connectors.
• Check connector pins for corrosion and ensure a clean, tight connection.
• Look for oil leaks near the sensor that could contaminate signals or wiring.
• Inspect the harness routing for heat exposure or chafing against moving parts.

C. Power and ground checks

• Verify the CKP sensor circuit supply and reference are within spec. Depending on the design (two-wire, three-wire, or three-wire with a reference), test:
  • 5V reference (if applicable) from PCM to the CKP sensor.
  • Continuity of the signal/wire from the sensor to the PCM.
  • Ground continuity to the sensor’s ground circuit.
• Check for blown fuses or relay issues that could affect the CKP circuit (if your vehicle’s wiring diagram shows a dedicated CKP fuse).
• Inspect the PCM power and ground connections to rule out a PCM-side fault.

D. Live data and waveform testing

• Using a scan tool with live data (or an oscilloscope), monitor the CKP signal while cranking:
  • A healthy CKP should show a clear, consistent pulse train or waveform as the engine rotates.
  • If there is no signal, intermittent signal, or a waveform that looks erratic or heavily noisy, suspect CKP sensor, harness, or reluctor alignment.
• If the vehicle has more than one crank/cam sensor, verify that camshaft signals are reasonable too, to help isolate whether the issue is crank-related or timing-related.

E. Mechanical timing considerations

• If timing components were recently serviced or there is suspected timing tensioner/chain/belt wear, verify that the crank sensor’s reluctor wheel and tone ring are intact and properly aligned with the sensor.
• Any non-original timing work or engine timing misalignment can mimic or cause P0335 symptoms.

F. Sensor testing options

• CKP sensor resistance tests: Some CKP sensors have specific resistance specs. If available for your engine, measure resistance between the sensor terminals to check for out-of-range values.
• Signal test: With the engine cranking, inspect the CKP signal line for a steady signal. If using an oscilloscope, verify a clean, repeating waveform without gaps.
• Wiring harness test: Perform a continuity test from the CKP sensor connector to the PCM harness to verify there are no open or short circuits, including checking for unintended grounding or shorts to adjacent circuits.

G. Troubleshooting decision tree (summary)

• If CKP sensor shows a solid signal but PCM reports a fault, re-check wiring/connectors and refer to the vehicle’s wiring diagram for possible short to ground or reverse polarity scenarios.
• If no CKP signal is present during cranking, suspect CKP sensor or wiring harness first, then PCM if the wiring checks out.
• If timing components are suspect (misaligned or damaged reluctor), address timing issues before continuing diagnostics, as incorrect timing can cause false CKP faults or no-start.

RELATED CODES

• P0330–P0334: Various CKP-related or timing-related signals; often used to indicate broader crank/cam synchronization issues or other CKP circuit concerns.
• P0336: Crankshaft Position Sensor A Circuit Range/Performance
• P0337: Crankshaft Position Sensor A Circuit Low Input
• P0338: Crankshaft Position Sensor A Circuit High Input
• P0339: Crankshaft Position Sensor A Circuit Intermittent (varies by system)
  Note: The exact related codes can vary by model year and sub-model; use a scan tool to review any concurrently stored CKP-related codes.

REPAIR OPTIONS AND COSTS (2025 PRICES)

Prices vary by region, shop, and whether OEM or aftermarket parts are used. The following are typical ranges for a 2017–2023 Subaru Impreza in the United States. All prices are approximate and include parts and labor unless noted otherwise.

• Crankshaft Position Sensor (CKP) replacement

  • Parts: $20–$180 (aftermarket commonly on the lower end; OEM higher)
  • Labor: 0.5–1.5 hours
  • Typical total: $100–$350

• CKP sensor wiring/connector repair or harness replacement

  • Parts: $20–$150 (harness or connector)
  • Labor: 1–3 hours
  • Typical total: $150–$600

• PCM/ECU replacement (if PCM fault is determined and other causes ruled out)

  • Parts: $300–$1200 (varies by OEM vs. rebuilt units)
  • Labor: 2–4 hours (plus programming/initial setup)
  • Typical total: $700–$1800

• Timing-related repairs (timing belt/chain, tensioner, guides) if discovered

  • Parts: $100–$800 (depends on parts used and engine)
  • Labor: 3–6 hours
  • Typical total: $600–$2400

Notes:

• In many cases, diagnosing P0335 first targets the CKP sensor and wiring. Replacement of the CKP sensor is a common first repair, with wiring repairs following if the sensor tests OK but the fault persists.
• If a timing-related mechanical fault is discovered (timing chain, belt, tensioner), that work can substantially raise the total cost.
• These ranges assume typical shop rates in the US; rates in other regions or at dealership including diagnostic charges may differ.

DIY vs PROFESSIONAL

• DIY feasibility:
  • Pros: If you have basic electrical test equipment (digital multimeter, oscilloscope if available), willingness to follow a systematic diagnostic path, and access to replacement CKP sensors, you can save on labor costs.
  • Cons: The CKP sensor location for some Impreza models may require removal of belts or other engine components. Faults can be intermittent or electrical in nature, so proper testing is essential to avoid unnecessary parts replacement.
• DIY steps to attempt:
  • Equip yourself with a service manual or wiring diagram for your exact engine variant (2.0L or 2.5L in the Impreza).
  • Perform visual inspection of CKP sensor and harness; fix any obvious damage or corrosion.
  • Check fuses/relays related to the CKP circuit.
  • If you have access to a scope or a good scan tool, monitor the CKP signal during cranking to confirm presence and quality of the signal.
  • If CKP signal is missing or erratic and the harness is sound, replacing the CKP sensor is a reasonable next step.
• Professional considerations:
  • A qualified technician can perform advanced electrical tests (scope waveform analysis, PCM communication checks) and confirm wiring integrity more efficiently. They can also reprogram/initialize PCM if required after sensor replacement.

PREVENTION

• Regular maintenance to avoid sensor contamination:
  • Keep the engine bay clean and check for oil leaks that could contaminate electrical connectors.
  • Address oil or coolant leaks promptly; moisture can cause corrosion on sensor connectors.
• Electrical connection care:
  • Ensure battery terminals and grounds are clean and secure; poor grounds can mimic sensor faults.
  • Use dielectric grease on connectors to resist corrosion and moisture.
• Driving habits:
  • Address unresolved misfires quickly; intermittent misfires can lead to catalyst damage and other engine issues.
• Timing maintenance:
  • If your Subaru uses a timing belt-driven timing system or a chain with tensioners, adhere to the manufacturer’s service interval and have timing components inspected or replaced as recommended, especially if CKP symptoms appeared after timing work.

Data limitations and transparency

• The provided data indicates no NHTSA complaints for this exact combination and no recalls for P0335 on Subaru Impreza (2017–2023). This guide uses general CKP knowledge and Subaru-specific considerations to outline diagnostic steps, probable causes, and repair options. If new recalls, TSBs, or service advisories become available, they should be consulted and followed.
• Actual costs, service steps, and repair difficulty may vary by engine type (e.g., 2.0L FA20 vs. 2.5L FB25) and by retailer or independent shop.