P0345 Code: Nissan Altima (2019-2023) - Causes, Symptoms & Fixes

Data note (per your provided dataset)

• No NHTSA owner complaints found for P0345 on 2019–2023 Nissan Altima.
• No recalls found in the NHTSA database for this make/model/year/issue.
• No recalls found in NHTSA database.
• Data limitations: The absence of complaints/recalls in the dataset does not guarantee the issue does not occur in the real world. This guide uses general automotive knowledge for tech explanations, with the data limitations clearly noted.

Comprehensive diagnostic guide for P0345 on 2019–2023 Nissan Altima

CODE MEANING AND SEVERITY

• Code P0345 = Camshaft Position Sensor A Circuit Bank 1 malfunction (sensor A circuit fault for Bank 1 camshaft position sensor).
• What it means: The engine control module (ECM/PCM) detects an abnormal condition in the camshaft position sensor A circuit for Bank 1, or it cannot receive a valid signal from the sensor. This can be caused by a faulty sensor, wiring issues, or timing-related problems.
• Severity: Moderate to severe. Potential drivability issues include rough idle, misfires, stalling, reduced power, or a no-start condition. Prolonged driving with this code can worsen engine performance and fuel economy, and can increase the risk of damage due to misfire.

COMMON CAUSES ON NISSAN ALTIMA

• Faulty camshaft position sensor (CMP sensor) A (Bank 1)
• Damaged or corroded CMP sensor wiring or harness connector (loose connection, broken insulation, bent pins)
• Open, short to ground, or short to battery in sensor circuit
• Faulty 5V reference or ground circuit from PCM
• Timing issues related to cam timing (timing chain/belt wear, tensioner or guides, or a stuck/weak variable valve timing (VVT) solenoid) causing the CMP signal to be out of spec or absent
• Oil ingress or contamination on the CMP sensor or harness
• PCM/ECM fault or intermittent communication issue
• Intermittent issues often involve sensor wiring or connector problems rather than a failed sensor alone
• Related possibility in some Altima setups: issues with crankshaft position sensor (P0335/P0336) can coexist or mimic CMP issues; always check for multiple DTCs

SYMPTOMS

• Check Engine Light (CEL) or MIL illuminated
• Rough idle or misfires
• Hesitation, stalling, or difficulty starting
• Poor engine performance or reduced power
• Decreased fuel economy
• Intermittent driveability issues (especially after engine heat soak or during cold start)
• In some cases, no-start condition

DIAGNOSTIC STEPS

Note: Work safely. If you must, disconnect the battery only when the engine is off and sensors are being serviced.

A. Preparation

• Retrieve and record the DTC and freeze-frame data with a high-quality scan tool.
• Note any accompanying codes (e.g., P0335/P0336 for crank sensor, P0300-series misfire codes, or P0011/P0014 for VVT). These can help with diagnosis.

B. Visual and basic electrical inspection

Inspect CMP sensor and harness

• Locate Bank 1 camshaft position sensor. On many Nissan QR/VC-T engines, it sits near the timing chain cover or cylinder head area.
• Inspect for signs of heat damage, oil contamination, corrosion, bent pins, or loose connectors.
• Disconnect and inspect the sensor connector and sensor pins; look for corrosion, bent terminals, or loose fit.

Check wiring harness and connectors

• Inspect the entire CMP sensor circuit from PCM reference to the sensor: 5V reference, signal output, and ground wires.
• Look for damaged insulation, chafed wiring, or harness routing that may contact hot surfaces or moving parts.
• Wiggle-test the connector with the ignition ON to see if the DTC returns or signal fluctuates (careful to avoid shorts).

C. Electrical tests

Confirm 5V reference and ground at the CMP sensor

• With key ON and engine OFF, back-probe the CMP sensor connector to verify:
  • 5V reference at the correct pin (from PCM)
  • Ground at the ground pin
  • Good, low-resistance path to PCM ground
• If no 5V reference or poor ground is found, fix wiring or connector before re-testing.

Inspect sensor signal circuit

• Start the engine and observe the CMP sensor signal voltage with a scope or high-quality multimeter (some scanners can show live waveform).
• CMP sensor outputs a variable voltage/signal corresponding to camshaft position; a missing or erratic signal indicates sensor or wiring fault.
• Check for signal consistency across RPM range. A flat line or highly erratic signal is a red flag.

Resistance test of the CMP sensor (if service data/specs available)

• Some sensors have a resistance specification across the sensor pins or between sensor pins and ground. Compare with factory specs. Abnormal resistance can indicate a defective sensor.

D. Mechanism and timing checks

Inspect timing components

• If engine timing is suspected (e.g., misalignment, jumped timing, stretched chain, worn tensioner), inspect timing chain/belt, tensioner, guides, and cam/crank gears.
• A mis-timed engine can produce false or missing CMP signals.

Check for oil or contamination

• Excess oil in the CMP area or contaminated sensor can affect readings. Clean or replace as needed; ensure seals and orings are intact.

E. Cross-check with related sensors

• If P0335/P0336 (crankshaft position sensor) codes are present, verify crank sensor operation. Many engines rely on both cam and crank position sensors for timing; a fault in the crank sensor can mimic CMP issues, and vice versa.

F. Component replacement decisions

• If CMP sensor and wiring test good but the code persists, consider replacing the CMP sensor as a reasonable next step.
• If timing components show wear or improper timing alignment, address timing system before replacing sensor to avoid recurring faults.

G. PCM considerations

• In rare cases, the PCM/ECM may be at fault. This is less common, but if wiring and sensor tests pass with no resolution, PCM diagnostics or replacement may be considered by a qualified technician.

RELATED CODES

• P0340: Camshaft Position Sensor Circuit Malfunction (generic CMP circuit issue)
• P0344: Camshaft Position Sensor Circuit Intermittent
• P0335: Crankshaft Position Sensor A Circuit Malfunction
• P0336: Crankshaft Position Sensor A Circuit Range/Performance
• P0300–P0308: Random/Multiple/Misfire cylinder codes (may accompany CMP issues)
  Note: This guide follows the data you provided; no recalls or TSBs are cited from the dataset.

REPAIR OPTIONS AND COSTS (2025 PRICES)

Prices vary by region, shop, and whether you choose OEM vs aftermarket parts. The ranges below are typical for 2025 labor markets in many U.S. shops.

• Diagnostic fee

  • Typical: $80–$150 (shop diagnostic time to confirm DTC, inspect, test, and advise)

• Camshaft Position Sensor (CMP) replacement (Bank 1)

  • Parts: $30–$120 (aftermarket sensor; OEM may be higher)
  • Labor: 0.5–1.0 hour
  • Total estimated: $120–$300 (roughly)

• CMP sensor wiring/connector repair

  • Parts: $10–$60 (insulation, connectors, possibly a short wiring harness segment)
  • Labor: 0.5–1.0 hour
  • Total estimated: $70–$250

• Timing chain/belt, tensioner, or related timing components (if timing is found to be off)

  • Parts: $100–$400 (timing components) plus any sensors/o-rings
  • Labor: 2.0–5.0 hours depending on engine and access
  • Total estimated: $500–$1,800
  • Important: If timing components require service, this is a substantial repair and should be confirmed with a trustworthy timing reference check before proceeding.

• PCM replacement (rare)

  • Parts: $400–$1,000 (new PCM)
  • Labor: 2.0–4.0 hours
  • Total estimated: $1,000–$2,800
  • Note: PCM replacement is unusual for P0345 without other indicators; usually sensor or wiring fixes suffice.

• Used parts approach

  • CMP sensor: typically cheaper but carries risk; ensure warranty on used sensor
  • Labor remains the same; you could save on parts if a known-good used sensor is obtained, but only from reputable sources.

• Summary guidance

  • Most P0345 cases in Altima arise from sensor or wiring faults, not full timing replacement.
  • Expect most repairs to stay in the $100–$350 range if only the sensor is replaced and timing is confirmed to be OK.

DIY VS PROFESSIONAL

• DIY considerations

  • Pros: Lower parts cost, learning opportunity, satisfaction of completing the repair.
  • Cons: Access to timing components may be cramped; risk of mis-timing if you inadvertently disturb timing. Proper safety practices and a service manual are essential.
    Steps you might take as a DIY:
    • Verify fault with a good scan tool, inspect wiring and connectors, and check 5V/ground references.
    • If you have access to a scope, observe the CMP signal waveform and compare to expected pattern.
    • If sensor/wiring checks are clean and you’re able to safely replace the CMP sensor, follow manufacturer torque specs and use dielectric grease on connectors.
    • Re-check after replacement to confirm code clears and no new codes appear.

• Professional considerations

  • A shop can perform more thorough timing checks (timing marks, tensioner) and use professional-grade diagnostics to verify the CMP signal and timing alignment.
  • Pros are advisable if you suspect timing issues, PCM faults, or if replacing the sensor does not resolve the issue.

PREVENTION

• Regular maintenance
  • Use the manufacturer-recommended oil grade and change intervals to preserve engine tolerances and sensor reliability.
  • Keep oil clean and at proper levels; improper oil can contaminate the sensor area or affect VVT solenoids.
• Protect wiring and connectors
  • Inspect engine bay wiring harnesses periodically for wear, chafing, or heat damage.
  • Use dielectric grease on electrical connectors and ensure connectors latch properly.
• Address oil leaks promptly
  • Oil leaks near the camshaft area can contaminate the CMP sensor. Fix leaks promptly to prevent sensor contamination.
• Avoid harsh engine environments
  • Rapid temperature fluctuations and excessive heat can degrade sensors over time; ensure cooling system is functioning properly.

Closing notes

• Based on the provided data, there are no NHTSA recalls or complaints specific to P0345 for 2019–2023 Nissan Altima in the dataset. No recalls found in NHTSA database.
• This guide provides a practical diagnostic framework using general automotive principles and model-agnostic CMP knowledge, tailored for the Altima. If you are unsure or uncomfortable with timing-related investigations, seek a professional technician to avoid potential engine timing damage.