P0505 Code: Toyota Camry (2018-2024) - Causes, Symptoms & Fixes

Below is a comprehensive diagnostic guide for OBD-II code P0505 (Idle Control System Malfunction) as it can appear on 2018–2024 Toyota Camry models. Note on data used: the provided NHTSA data for 2018–2024 Camry shows no recalls for this model and does not include a P0505 complaint in the dataset. There is one owner complaint in the dataset about a different code (P0442). Because P0505 is a common idle-control concern across many vehicles, this guide uses general automotive knowledge tailored to Toyota Camry with the caveat that model-specific service procedures may vary by year and powertrain. Always consult the vehicle’s service manual or a Toyota-compatible scan tool for exact procedures.

CODE MEANING AND SEVERITY

• What P0505 means: P0505 stands for Idle Control System Malfunction. On Camry models from 2018–2024, the engine management system controls idle via an electronically controlled throttle body (and an integrated idle control function). If the engine control module (ECM/ECU) detects idle speed that is not within the expected range while at idle, it stores P0505.
• Severity and impact: Moderate. A faulty idle control can cause rough idle, stalls, or fluctuating idle, which can affect drivability and emissions readiness. Not typically an imminent safety hazard, but a vehicle that stalls at idle or revs unexpectedly can create dangerous situations in certain scenarios (e.g., stopping at intersections). Address promptly to avoid further drivability issues and potential emissions concerns.

COMMON CAUSES ON TOYOTA CAMRY (2018–2024)

• Dirty or sticky throttle body (including the idle air passages) and minor carbon buildup.
• Integrated Idle Control (IAC) function inside the throttle body is sticking or not moving freely.
• Vacuum leaks in intake/PCV hoses, intake manifold gaskets, throttle body vicinity, or cracked vacuum lines.
• Dirty or faulty mass air flow (MAF) sensor or incorrect air measurement affecting idle.
• TPS (Throttle Position Sensor) or other sensor readings that cause improper idle control at rest.
• EGR valve stuck open or partially blocked (increases intake of exhaust gas at idle, upsetting idle speed).
• Low fuel pressure or inconsistent fuel delivery affecting idle stability.
• Electrical issues: damaged wiring harness, corroded connectors, or poor grounds related to the throttle body, MAF, or ECM.
• Idle relearn/calibration required after cleaning/removal of throttle body or battery disconnect.
• In rare cases, a faulty ECM/TCM or communication/wiring issue can set P0505.

SYMPTOMS TO EXPECT

• Rough idle (surges, dips, or unstable RPM at idle).
• Idle RPM higher or lower than expected when the engine is at operating temperature.
• Stalling or occasional difficulty starting/stalling while coming to a stop.
• Check Engine Light (MIL) illuminated; possible related codes (P0505 with other P-codes present).
• Hesitation or bucking at light throttle in idle transition.
• Possible reduced fuel economy if idle control is not functioning properly.

DIAGNOSTIC STEPS (step-by-step approach)

Note: Use a Toyota-compatible scan tool (Techstream or similar) if available for live data and special idle relearn procedures. If you don’t have access, you can still perform basic checks, but some steps require advanced tooling.

A. Verify and document

• Retrieve codes with scanner. Confirm that only P0505 is present or if there are other codes (P0506, P0507, P1122, P0101, P0171/ P0174, etc.) that could contribute to idle issues.
• Record live data at idle: engine RPM, commanded RPM (if available), throttle position, MAP/MAF readings, IAC/ETB position (if shown), engine coolant temperature, and fuel trim. Look for abnormal readings.

B. Visual and mechanical inspection

• Inspect for obvious vacuum leaks: cracked hoses, loose intake clamps, cracked intake manifold, and PCV hose condition.
• Check intake area for excessive carbon or dirt around the throttle body and idle passages.
• Inspect throttle body for sticking or binding of the throttle plate; ensure the throttle linkages/connectors are secure.
• Check the MAF sensor and air intake path for dirt or contamination; ensure air filter is clean.

C. Vacuum and air measurement checks

• Perform a basic vacuum leak test. If equipped, use a handheld vacuum gauge or perform a smoke test to locate leaks around intake manifold, gaskets, throttle body, and vacuum hoses.
• If readings indicate abnormal air intake (e.g., MAF readings not consistent with MAP/engine speed), inspect or clean MAF; ensure calibrations are correct and there are no oil contamination issues on the MAF element.

D. Throttle body and idle control

• Clean the throttle body and idle passages with approved throttle-body cleaner. Avoid aggressive scraping that could damage passages.
• Check the operation of the idle control function. If you have access to a scan tool:
  • Run any “idle relearn” or “throttle body alignment” or “idle speed learning” procedure as prescribed by Toyota for your year/model. This step recalibrates the ECM’s idle target to match the actual mechanical setup after cleaning or part replacement.
  • If the idle control is electronic and the IAC is separate, verify the IAC valve has full travel and moves smoothly.
• If idle control cannot be calibrated or the IAC/ETB cannot move freely, consider throttle body replacement or IAC valve replacement (if service documentation confirms a separate IAC).

E. Sensor checks and related systems

• MAF sensor: clean if dirty; test after cleaning to see if idle improves. Consider replacement if readings remain out of spec.
• TPS: test for smooth response when moving from idle to wide-open throttle (WOT) to ensure the sensor isn’t producing erroneous idle setpoints.
• EGR valve: inspect for sticking or carbon buildup; clean or replace if necessary.
• Fuel system: verify fuel pressure is within specification for the Camry’s engine (particularly for idle stability). Low pressure can cause idle and drivability issues.

F. Electrical and mechanical checks

• Inspect wiring and connectors to the throttle body, MAF, TPS, and ECM for damage, corrosion, or loose connections.
• If applicable, check the ECM/ECU fuse and grounds. A bad ground can affect idle control circuits.
• If all mechanical and sensor checks are within spec and weather conditions aren’t a factor (e.g., temperature fluctuations), perform a controlled test drive to confirm the issue persists and capture live data.

G. If no external cause is found

• Consider ECM or transmission/engine control module issues or intermittent wiring faults. In rare cases, a software update or reflash may be necessary; only perform such steps with dealer-level tools and procedure.

H. Post-repair verification

• After any cleaning, part replacement, or idle relearn, clear codes and drive the vehicle to allow the ECM to relearn idle under normal conditions.
• Recheck for P0505 and ensure idle is stable at operating temperature across multiple idle conditions (cold start, after warm-up, during deceleration).

RELATED CODES

• Idle control family (commonly associated or co-present): P0506 (Idle RPM Lower than Expected), P0507 (Idle RPM Higher than Expected), P0508 (Idle Air Control System Overspeed/Interference) – depending on OEM definitions for the model year.
• Other codes that can affect idle stability: P0101–P0103 (MAF sensor), P0120–P0122 (TPS), P0171/P0174 (fuel trim lean/rich), P0300 (random/multiple cylinder misfire).
• EGR-related codes (P0400–P0404 range) may appear if EGR is involved in idle instability.

REPAIR OPTIONS AND COSTS (2025 PRICES)

Prices vary by region, shop, and whether a Camry has a traditional throttle body or a fully integrated throttle-by-wire setup. All prices are rough ranges for parts and labor; actual quotes can differ.

• Throttle body cleaning (with electronic throttle control)

  • Parts: usually none or minimal if cleaning only
  • Labor: $60–$180
  • DIY: low (if you already have basic tools)

• Throttle body replacement (if cleaning fails or throttle body is defective)

  • Parts: $250–$700 for a replacement throttle body (OEM or high-quality aftermarket)
  • Labor: $150–$350
  • Total: roughly $400–$1,050

• Idle air control (IAC) valve replacement (if separate from throttle body)

  • Parts: $80–$250
  • Labor: $70–$150
  • Total: roughly $150–$400

• Vacuum leak repair (hoses, gaskets, intake manifold seals)

  • Parts: $10–$200 (depends on hose/gasket replacement)
  • Labor: $100–$350
  • Total: roughly $110–$550

• MAF sensor cleaning or replacement

  • Cleaning (DIY): $0–$20
  • Replacement: $60–$300 (sensor itself)
  • Labor: $40–$100

• EGR valve cleaning or replacement

  • Cleaning: $0–$60 (DIY)
  • Replacement: $180–$560 parts
  • Labor: $100–$250

• PCV valve replacement

  • Parts: $5–$25
  • Labor: $50–$100

• Idle relearn procedure (labor only; no parts)

  • Typically included in diagnostic time or standard service after throttle/body work

Notes:

• If a dealership or specialized Toyota shop is used, the price may be higher due to OEM parts and labor rates.
• In a few Camry variants, the idle control is fully integrated into the electronic throttle body, so an IAC issue may be resolved by throttle body service or replacement rather than a separate valve.

DIY VS PROFESSIONAL

• DIY considerations:
  • Great for cleaning the throttle body and performing a basic vacuum leak check with simple tools.
  • Safe handling of basic electrical connectors and sensors is required.
  • You can save on labor by cleaning/inspecting major items and performing idle relearn if your tool supports it.
• Professional considerations:
  • A qualified tech can perform precise live data diagnosis, carry out proper idle relearn, validate fuel trims, perform a smoke test for vacuum leaks, and verify throttle body calibration with OEM software.
  • If the issue requires throttle body replacement or ECM work, professional service is recommended.
• Decision criteria:
  • If your idle issue persists after a thorough cleaning and basic checks, or if you notice multiple related codes or poor drivability, seek professional diagnostics.

PREVENTION

• Routine maintenance helps minimize idle-control issues:
  • Regular air filter replacement and ensuring clean intake paths.
  • Periodic MAF sensor cleaning (or replacement if faulty) and ensuring the MAF is not contaminated by oil or dirt.
  • Inspect and replace vacuum hoses and PCV valve as recommended by Camry maintenance schedule.
  • Keep the throttle body clean; avoid heavy carbon buildup by using quality fuel and fuel system cleaners occasionally.
  • If you perform any electrical work on the throttle body or related sensors, ensure connectors are clean and well-seated, and perform any required idle relearn afterward.
  • If your Camry has a software/TCM/ECU update from Toyota, ensure the vehicle’s software is up to date, as some idle issues can be resolved with firmware revisions (note: confirm updates with the dealer or a Toyota-approved scanner).

Data limitations and context

• The provided data set shows no recalls for the Camry in 2018–2024, and there is no P0505 complaint entry in the dataset. This guide uses general idle-control knowledge and Camry-specific considerations to help diagnose P0505 when it appears on these model years. If you have service bulletins (TSBs) or recalls for your exact vehicle year and trim, follow those official documents first. The idle-control procedure can vary by engine variant (2.5L, 3.5L V6, etc.) and by whether the throttle is a traditional or electronic unit.
• If you are unsure about any step or do not have the proper tools, seek professional diagnostic help to avoid misdiagnosis or unintended damage.

If you want, tell me your Camry’s engine variant and whether you observe any other codes or symptoms, and I can tailor the diagnostic steps and cost estimates more precisely.