P0336 Code: Subaru Forester (2019-2024) - Causes, Symptoms & Fixes

Sections: 1) CODE MEANING AND SEVERITY 2) COMMON CAUSES ON SUBARU FORESTER 3) SYMPTOMS 4) DIAGNOSTIC STEPS 5) RELATED CODES 6) REPAIR OPTIONS AND COSTS (2025 prices) 7) DIY vs PROFESSIONAL 8) PREVENTION

Data note: No recalls found in NHTSA database. The REAL NHTSA data for 2019-2024 Subaru Forester shows no owner complaints or recalls specifically tied to this issue.

CODE MEANING AND SEVERITY

• Code meaning: P0336 = Crankshaft Position Sensor A Circuit Range/Performance. This means the PCM detected the crankshaft position sensor signal was out of the expected range or not switching with proper consistency. The sensor provides the engine’s crank position timing information; when its signal is abnormal, the engine may not operate reliably.
• Severity and driveability:
  • Could cause rough idle, misfires, stalling, or no-start conditions.
  • In some cases the engine may run poorly or enter a "limp mode," or the check engine light (CEL) will stay on.
  • Infrequently, you may be able to drive short distances, but continued operation risks potential damage or failure to restart.
• Data note: No recalls found in NHTSA database for this issue on these model years.

COMMON CAUSES ON SUBARU FORESTER

• Faulty crankshaft position sensor (CMP) itself.
• Damaged, corroded, or loose wiring/connectors to the CMP (insulation wear, pin corrosion, moisture intrusion).
• Poor ground or power supply to the sensor (failed ground strap or power circuit).
• Oil, coolant, or dirt/moisture intrusion around the sensor or connector.
• Mechanical timing issues (timing chain tensioner, timing chain wear, or reluctor/ring damage) causing irregular or out-of-range sensor readings.
• Sensor installation issues after service (misaligned sensor, incorrect torque on mounting).
• ECU/PCM fault (less common; typically accompanied by other codes).
• Aftermarket wiring, adapters, or modifications that affect crank signal integrity.

SYMPTOMS

• Check Engine Light (CEL) or MIL illuminated with P0336 stored or pending.
• Rough idle or misfires; engine may feel intermittently unstable.
• Difficulty starting or intermittent no-start.
• Reduced engine power or drivability concerns; engine may go into limp mode in some scenarios.
• Occasional stalling or hesitation, especially at idle or low RPM; may recover when driving at higher RPM.
• No obvious foreign noises, but intermittent electrical symptoms are possible.

DIAGNOSTIC STEPS

Note: This is a structured approach you can follow or have a technician perform. Start with the simplest checks and progress to more involved tests as needed.

• Step 1: Confirm the problem

  • Use an OBD-II scanner to confirm P0336 is present and note any freeze-frame data and any related codes (e.g., P0335).
  • Check for other crank/cam-related codes that could indicate a broader sensor or timing issue.

• Step 2: Visual inspection

  • Locate the crankshaft position sensor (location varies by engine type in Forester; commonly near the crank pulley or timing cover).
  • Inspect the sensor and its wiring harness for obvious damage, loose connections, pin corrosion, oil leaks, or displaced clips.
  • Check the connector for moisture, corrosion, bent pins, or damaged seals. Re-seat if needed.

• Step 3: Inspect or test the wiring

  • Inspect the harness for chafed insulation, exposed conductors, or wiring that rubs against moving parts.
  • Check the ground and power circuits to the CMP if you have wiring schematic access: continuity to ground, and correct supply voltage when key is on (using a multimeter with the harness disconnected as needed).
  • If possible, perform a continuity/resistance check from the PCM connector to the CMP connector to detect open circuits or shorts.

• Step 4: Inspect mechanical timing and reluctor/ring (if indicated)

  • If other timing-related codes appear, or if the engine has symptoms of being out of time (hard starting, mis-timed RPM behavior), inspect timing chain/belt (if applicable to the engine variant) and the reluctor ring for damage or misalignment.
  • Note: In most modern Subaru Foresters with a timing chain, significant timing issues are less common than sensor/wiring faults, but they can cause the CMP reading to be out of range.

• Step 5: Sensor and signal testing

  • With the engine cranking or running (if safe to do so), monitor CMP signal with a scope or a high-quality scan tool that can display live crank signal waveform.
  • Look for a clean, regular waveform with consistent amplitude and duty cycle. Missing pulses, sporadic spikes, or a flat line indicate sensor or wiring failure.
  • If the CMP signal looks abnormal or absent, replace the CMP and re-test.

• Step 6: Substitution/verification

  • If you have access to a known-good CMP or a tested spare, you can temporarily swap to verify if the code clears and the engine runs normally.
  • After replacing components, clear the codes and perform a road test to confirm the issue is resolved and no new codes appear.

• Step 7: ECU considerations

  • If after exhaustive sensor/wiring checks the code persists, consider ECU/PCM fault as a last resort. This is less common, and professional diagnosis is advised.

• Step 8: Test drive and re-check

  • Clear codes, drive normally to see if P0336 returns, and re-scan to confirm no other related codes appear.

RELATED CODES

• P0335: Crankshaft Position Sensor A Circuit Malfunction (broader category; sensor or circuit issue)
• P0340: Camshaft Position Sensor Circuit Malfunction (related to overall timing signals)
• Other crank/cam sensor codes in the same family may appear in tandem if there is a broader timing or signal issue. Exact codes can vary by model/year and the diagnostic tool.

REPAIR OPTIONS AND COSTS (2025 PRICES)

Prices can vary by region, shop, and whether you already own tools. US price ranges are given as typical guidelines.

• Option A: Replace Crankshaft Position Sensor (CMP) only

  • Parts: ~$25–$150
  • Labor: ~0.8–2.0 hours
  • Estimated total: ~$120–$420
  • Notes: This is the most common fix for P0336 when the sensor or its immediate circuitry is at fault.

• Option B: Clean/repair wiring and connectors; replace damaged harness sections if needed

  • Parts: ~$20–$120 for connectors or harness sections
  • Labor: ~0.5–2.0 hours
  • Estimated total: ~$100–$400
  • Notes: If wiring insulation is damaged or connectors are corroded but the CMP itself tests within spec, this can resolve the issue.

• Option C: Timing-chain/reluctor-ring or mechanical timing work (if timing issue is suspected)

  • Parts: Varies widely; timing chain kits, tensioners, guides
  • Labor: High; 3.0–8.0 hours depending on access and engine variant
  • Estimated total: ~$800–$2,000+ (or more)
  • Notes: This is far less common for a P0336 unless a mechanical timing fault is confirmed.

• Option D: ECU/PCM replacement or reflash

  • Parts: ~$400–$1,200+ (ECU cost varies)
  • Labor: Varies
  • Estimated total: ~$500–$2,000
  • Notes: Considered only after thorough sensor/wiring/timing checks fail and if no wiring fault is found.

• Additional prevention or ancillary work

  • Replacing agency connectors or applying dielectric grease to prevent future corrosion
  • Cleaning/repair of grounds if a grounding issue is found

DIY vs PROFESSIONAL

• DIY feasibility:
  • Replacing the CMP is commonly within DIY capability for someone comfortable with automotive electrical work.
  • You’ll need basic tools (socket set, multimeter, possibly a scope or a scan tool with live data), and a service manual or wiring diagram for your exact Forester engine variant.
  • Steps typically involve: disconnecting battery, locating CMP, disconnecting harness, removing sensor, installing new sensor, reconnecting harness, clearing codes, and road-testing.
• When to go pro:
  • Uncertain about wiring harness integrity, sensor testing with live data, or if timing chain work is suspected.
  • If faults persist after replacing the CMP and rechecking wiring.
  • If you do not have diagnostic tools (or the time) to verify sensor signal quality and timing.
• Safety notes:
  • Always disconnect the battery before working on electrical connectors near hot or moving engine parts.
  • Be cautious around high voltage/electrical systems and avoid creating shorts.

PREVENTION

• Regular inspection of the CMP wiring and connectors during routine maintenance or when you notice MIL illumination.
• Keep connectors clean and dry; replace degraded seals if you see moisture or oil intrusion.
• Protect wiring from chafing by securing harness routing away from moving components and hot surfaces.
• Address oil leaks promptly; oil exposure around the sensor can degrade signal quality.
• Use dielectric grease on electrical connectors during resealing to improve moisture resistance.
• If you perform maintenance on the timing system, ensure proper torque, alignment, and cam/crank timing references to avoid future sensor range issues.

Notes and limitations

• The data provided from NHTSA for 2019–2024 Subaru Forester shows no recalls or reported complaints for P0336 in this specific model/year combination, so no official recall data is cited here.
• The guidance above blends standard diagnostic practice for P0336 with model-agnostic knowledge and Subaru Forester engine layout considerations. Exact sensor location and wiring color codes can differ between engine variants (e.g., 2.5L vs. other engine options) and model years; consult the vehicle’s service manual or a Subaru-specific database for precise details.
• Repair costs are approximate and currency is USD. Prices can vary by region, shop, and availability of OEM vs aftermarket parts.