P0346 Code: Toyota Tacoma (2016-2023) - Causes, Symptoms & Fixes

Diagnostic guide for OBD2 code P0346 on 2016-2023 Toyota Tacoma

Data note and recalls

• Real NHTSA data for this make/model/year/issue: No owner complaints found.
• Official recalls: No recalls found in NHTSA database
• Data limitation: The dataset shows no complaints or recalls for P0346 in this specific model/year range. This guide uses general automotive knowledge for P0346 plus Tacoma-specific considerations, but actual vehicle behavior can vary. If you have service history or TSBs from Toyota, those are not cited here due to dataset limits.

CODE MEANING AND SEVERITY

• What P0346 means:
  • P0346 = Camshaft Position Sensor "A" Circuit Range/Performance (Bank 1 or Sensor A). The Powertrain Control Module (PCM) is seeing the camshaft position sensor signal outside the expected range or not consistent with engine timing.
• Why it matters:
  • The CMP sensor provides timing information used for ignition timing and, on many modern engines, for variable timing control. A bad signal can cause misfires, rough idle, poor acceleration, or no-start conditions.
• Severity:
  • Moderate to severe. If the sensor signal is erratic or out of range, the engine may run poorly, stall, or fail to start. Continuing to drive with a persistent P0346 can place added stress on catalytic converters due to misfires and unburned fuel.

COMMON CAUSES ON TOYOTA TACOMA

• Faulty camshaft position sensor (CMP) or its reluctor/sensor tooth target worn or damaged.
• Wiring harness damage to the CMP circuit (insulation wear, chafing, corrosion, open or short to ground/battery or to 5V reference).
• Poor or dirty/loose sensor connector or terminal corrosion.
• Oil contamination on the CMP sensor tip or in the connector, causing signal degradation.
• Timing-related issues (timing chain/buiding tensioner) causing irregular cam timing interpretation by the CMP signal.
• VVT (Variable Valve Timing) system oil flow or solenoid issues leading to timing discrepancies the PCM interprets as a sensor range problem.
• PCM/ECU glitches or an intermittent 5V reference or ground problem (less common but possible).
• Intermittent mechanical wear or debris in the camshaft area that alters the reluctor signal.

SYMPTOMS

• Check engine light (MIL) with P0346 stored.
• Rough idle or engine shaking at idle.
• Misfires, especially at certain RPMs or under load.
• Reduced power or hesitation during acceleration.
• Difficulty starting or no-start in some cases.
• Poor fuel economy due to misfiring or timing irregularities.
• InSome cases, stalling or sudden engine shutdown.

DIAGNOSTIC STEPS

Note: Follow safety procedures. When working near the timing cover, ensure the engine is off and the negative battery is disconnected as needed. If you are not comfortable, seek a professional.

• Step 0: Verify the DTC and data

  • Use an OBD-II scanner to confirm P0346 and check for related codes (P0340, P0344, P0010/11/12, P0300-P0308, etc.). Note freeze-frame data (RPM, engine load, sensor voltages, fault duration).

• Step 1: Visual inspection

  • Inspect CMP sensor and its wiring harness for obvious damage, wear, or oil leaks around the timing cover.
  • Check the sensor connector for corrosion, bent/loose pins, or a loose plug.
  • Look for oil leaks that could contaminate the sensor or harness.

• Step 2: Electrical checks (CMP sensor circuit)

  • With ignition OFF, disconnect the CMP sensor harness and inspect the pins. Reconnect after inspection.
  • Back-probe or use the PCM side of the harness to verify:
    • 5V reference to the CMP sensor (from PCM). If the 5V reference is absent or fluctuating, the issue may be the PCM or the reference circuit.
    • Ground continuity of the CMP sensor circuit to chassis/PCM ground.
  • If you have access to a multimeter:
    • Check for stable 5V reference at the sensor plug when the ignition is ON (engine not running).
    • Check for proper ground at the sensor plug.
  • If you have an oscilloscope or a data-logging tool:
    • Observe the CMP signal waveform. You should see a clean, periodic pulsed signal corresponding to camshaft teeth; irregular or missing pulses indicate a sensor or wiring problem.

• Step 3: Sensor and wiring testing

  • Exchange or swap CMP sensor with a known-good one if available (or swap to rule out a faulty sensor). Clear codes and test drive to see if the DTC returns.
  • Inspect and, if needed, repair/replace damaged wiring or connectors. Use dielectric grease on connectors to improve sealing.

• Step 4: Mechanical timing check

  • On many Tacomas, the CMP sensor reads the position of the camshaft timing gear/reluctor. If timing is off due to stretched chain, worn guides, or a failing tensioner:
    • Perform a mechanical timing check per the service manual. This may require removal of the timing cover.
    • Look for slack, wear, or misalignment of timing components. If timing is found off, you may need a timing chain kit (see Repair Options) and re-timing the engine.
  • Oil pressure and VVT solenoids should be checked for proper operation, as oil flow issues can affect cam timing and CMP readings.

• Step 5: Re-check after repairs

  • Reconnect battery, clear codes, and perform a proper test drive to ensure P0346 does not return. If it does, proceed with more in-depth diagnosis (PCM or additional sensing issues).

• Step 6: If the DTC persists after CMP replacement

  • Consider PCM/ECU issues or a deeper wiring fault. Re-check related circuits and consult the Toyota service manual for testing PCM inputs/outputs.

RELATED CODES

• P0340 Camshaft Position Sensor Circuit Malfunction (Bank 1 or Sensor A) – general sensor fault.
• P0344 Camshaft Position Sensor Circuit Intermittent.
• P0010, P0011, P0012 – Camshaft Timing/Variable Valve Timing related codes that can appear if VVT or timing is affected.
• P0300-P0308 – Misfires or misfire-related codes that can appear if CMP signal causes ignition misfires.
• P0335 Crankshaft Position Sensor Circuit – sometimes encountered when engine timing or sensor circuits are suspect; note that crank-related codes can interact with cam sensor interpretations.

REPAIR OPTIONS AND COSTS (2025 PRICES)

Prices vary by model year, region, whether you use OEM vs. aftermarket parts, and labor rates. The figures below are general ranges and reflect typical Tacoma pricing in 2025.

• Camshaft Position Sensor replacement (CMP sensor)

  • Parts: OEM Toyota sensor roughly $60–$180; aftermarket sensor typically $20–$80.
  • Labor: ~0.5–1.0 hour at a shop rate of $100–$180/hr.
  • Estimated total: $150–$350 (most commonly $180–$280 including parts and labor).
  • Notes: If the CMP sensor is replaced and the wiring is intact, the repair is usually straightforward.

• CMP sensor wiring/connector repair

  • Parts: Wiring harness repair or connector kit $10–$60.
  • Labor: 0.5–1.0 hour.
  • Estimated total: $60–$180.
  • Notes: If only wiring or connector is damaged, this is a cost-effective fix.

• Timing chain kit and related timing work (if timing is found to be off)

  • Parts (timing chain kit, tensioner, guides, seals): $250–$500.
  • Labor: 4–8 hours depending on engine access; $400–$1,500 labor depending on shop rate.
  • Estimated total: $650–$2,000.
  • Notes: This is a significant repair; only performed if a timing issue is confirmed.

• PCM/ECU replacement or reflash

  • Parts: PCM $350–$1,200 depending on model and remanufacture status.
  • Labor: 1–4 hours, depending on programming requirements.
  • Estimated total: $500–$1,800.
  • Notes: Rare; typically considered after thorough diagnostics show PCM faults.

• Miscellaneous costs

  • OBD-II scan tool, diagnostic time, and fluids if needed.
  • Expect diagnostic fees if performed at a shop, commonly $80–$150 per hour.

DIY vs PROFESSIONAL

• DIY viability:
  • CMP sensor replacement is commonly within DIY capability for a mechanically inclined owner. It is typically a straightforward sensor swap with basic hand tools, and no special equipment beyond a multimeter or oscilloscope is needed for basic testing.
  • Key DIY considerations: safely disconnecting the battery, locating the CMP sensor, disconnecting and reconnecting harness with clean terminals, using the correct torque if removing/installing bolts (refer to service manual), and ensuring the timing cover area is clean and free of debris.
• When to go pro:
  • If you suspect timing chain wear or tensioner issues, or if you hear unusual engine noises near the timing cover, professional service is advised.
  • If the CMP signal tests indicate a 5V reference or ground issue at the PCM harness, or if the PCM is suspected to be at fault, a professional diagnosis is recommended.
  • If the DTC persists after replacing the CMP sensor and wiring, or if you are not equipped to perform scope/diagnostic waveform testing, seek professional help.

PREVENTION

• Regular maintenance:
  • Follow Toyota’s recommended oil change intervals and use the correct oil grade to ensure proper lubrication of the engine and VVT system. Clean oil helps prevent CMP sensor contamination and oil varnish.
  • Keep oil leaks addressed promptly; oil on the CMP sensor can degrade signals.
• Electrical protection:
  • Inspect wiring harnesses and connectors around the CMP area at regular intervals, especially after any timing cover service or oil leaks.
  • Use dielectric grease on connectors during reassembly to improve corrosion resistance and sealing.
• Timing and VVT health:
  • Adhere to maintenance schedules that address VVT solenoids and timing-related components. Maintain clean oil passages to the VVT system to prevent erratic cam timing signals.
• Proactive diagnostics:
  • If you notice intermittent MIL illumination related to misfires or rough running, address early before the DTC progresses to more serious timing or sensor faults.

How to use this guide

• If you have a P0346 on a 2016–2023 Toyota Tacoma, start with a visual and electrical inspection of the CMP sensor and its wiring, confirm the 5V reference and ground, and check for oil contamination. If wiring and sensor check out, investigate timing and VVT components only as needed. Replace the CMP sensor if necessary, and re-test. If the DTC recurs or you find timing issues, consider more extensive repairs as outlined above.

Important reminder about data

• No recalls found in NHTSA database for this issue in this model/year, per the provided dataset.
• No complaints listed in the provided data for this exact issue, so this guide uses general diagnostic best practices and Tacoma-specific considerations rather than dataset-derived complaint patterns. If you have service history, TSBs, or updates from Toyota, those should be consulted alongside this guide.