P0335 Code: Ford F-150 (2021-2024) - Causes, Symptoms & Fixes

Comprehensive diagnostic guide for OBD2 code P0335 on 2021–2024 Ford F-150

Important data note (data limitations)

• Based on the provided data: No NHTSA owner complaints and no recalls found for 2021–2024 Ford F-150 relating to P0335. This means the guide below is largely built from general automotive knowledge and common industry practices for P0335, rather than a dataset of Ford-specific NHTSA cases. If you have access to factory service literature or TSBs, those can add vehicle-specific steps beyond this guide. Always correlate with your vehicle’s service manual and current Ford software/tools if available.

1. CODE MEANING AND SEVERITY

• P0335 stands for Crankshaft Position Sensor “A” Circuit Malfunction.
• What it means, in practical terms:
  • The Powertrain Control Module (PCM) did not receive a proper crankshaft position (CKP) signal in the expected timing window.
  • The engine may have difficulty starting, may run roughly, or may stall. In some cases, the condition can advance to a no-start situation.
• Severity on a Ford F-150:
  • High. The CKP signal is critical for ignition timing and fuel injection timing. A confirmed P0335 can prevent the engine from starting or cause drivability issues, and repeated occurrences can leave you stranded.
• Notes:
  • On many engines, P0335 can occur with other CKP-related codes (e.g., P0336, P0337, P0338, P0339) if the signal is intermittent or the circuit is marginal. Only P0335 indicates the “A” circuit malfunction.

2. COMMON CAUSES ON FORD F-150

• Faulty crankshaft position sensor (CKP) itself (sensor failure or internal short/open).
• Damaged, pinched, corroded, or disconnected CKP sensor wiring or connector.
• Bad or corroded ground/return path or 5V reference supply to the CKP sensor.
• Damaged crankshaft reluctor ring or misalignment of the CKP sensor relative to the reluctor (teeth damaged, missing teeth, or sensor mounting loose).
• Engine timing or front cover work where the CKP sensor was disturbed or not torqued correctly.
• PCM/ECM fault or software glitch (less common, but possible).
• Water intrusion, oil leaks, or contamination at the sensor or connector.
• Prior electrical work near the harness causing unintended damage to the CKP circuit.

3. SYMPTOMS

• Engine cranks but does not start (no spark/fuel timing correlation).
• Engine starts intermittently or stalls while running, then may not restart.
• Rough idle or misfire symptoms that don’t clearly map to a single cylinder.
• Check Engine light with code P0335 stored and possibly pending.
• In some cases, reduced engine power or limp mode may occur if multiple sensors are affected.
• No obvious mechanical damage (timing belt/chain intact), but irregular crank signal is detected.

4. DIAGNOSTIC STEPS
   Tools you may need:

• Dipstick/scan tool with live data (freeze frame and CKP signal waveform capability)
• Multimeter (DMM)
• Optional: Oscilloscope for CKP waveform verification
• Service manual or Ford IDS/OF-Tool-compatible scanner for sensor data when available

Step-by-step procedure (structured approach)
Step 0 – Confirm and document

• Retrieve the Freeze Frame data with your scan tool: note engine RPM, fuel trim, ignition status, and any other codes present.
• Confirm that the only code is P0335 or if additional CKP/CMP-related codes are present (e.g., P0336, P0330, P0340). Note recent events (weather, water exposure, repairs).

Step 1 – Visual inspection

• Inspect CKP sensor, its connector, and wiring harness for obvious damage: frayed insulation, cracked/loose connectors, bent pins, corrosion, or water intrusion.
• Look for signs of oil leaks near the sensor, which can degrade performance or cause contamination.
• Inspect the crank pulley/flywheel area (where the reluctor ring is located) for damage or debris.

Step 2 – Electrical checks on the CKP circuit

• With ignition OFF, disconnect the CKP sensor connector.
• Check for continuity between the sensor pins and the PCM/ECU harness as specified in the service manual (reference wiring diagrams). Look for breaks or high resistance.
• Check the 5V reference circuit: with ignition ON, back-probe the reference wire at the PCM side or the sensor side to confirm ~5V reference voltage. A missing or low reference indicates wiring harness problems or PCM output failure.
• Check the CKP signal circuit: back-probe the CKP signal wire to see if the PCM is receiving a signal during crank. If you can observe a waveform with an oscilloscope or a compatible scanner, you should see a periodic signal while cranking.
• If you lack an oscilloscope, a basic check is: with ignition ON (engine OFF), does the signal wire show 0V (no signal) or a voltage that is within expected reference behavior when cranking? Absence of a clean signal is a red flag for sensor or wiring failure.

Step 3 – Mechanical verification

• Verify the CKP sensor mounting: ensure it is properly seated, torque to spec, and not loose.
• Check sensor alignment relative to the reluctor ring. Any misalignment or space gap that exceeds spec can cause misreads or no signal.
• Inspect the reluctor ring teeth for missing teeth, damaged teeth, or warping; damage here can produce irregular signals.

Step 4 – Sensor replacement test (diagnostic confirmation)

• If visual and electrical checks point to the CKP circuit or sensor, perform a controlled sensor swap with a known-good CKP sensor:
  • Use OEM or reputable aftermarket CKP sensor.
  • Replace with the engine off, disconnect the battery before removal.
  • Reconnect harness, torque to spec, and recheck all connections.
  • After replacement, clear codes and attempt to start. If P0335 no longer returns, sensor fault was confirmed.
• If available, temporarily connecting a known-good CKP sensor (from a similar vehicle if permissible) can help confirm whether the sensor is the root cause (do not drive with a makeshift test sensor—only for diagnostic confirmation in a controlled environment).

Step 5 – Further diagnostic if symptoms persist

• If P0335 persists after a sensor replacement:
  • Re-check the 5V reference and signal circuit for continuity and proper grounding.
  • Inspect for any PCM-related issues if multiple CKP-related codes appear or if the signal is consistently erratic despite a new sensor and clean wiring.
  • Consider wiring harness chafing near moving components; the harness could be being worn by the serpentine belt or other engine components.
  • In cases where the crankshaft reluctor ring has been damaged or timing components were recently serviced, re-check timing and mechanical alignment.
• If the vehicle starts intermittently but then fails again, consider performing an extended monitoring test with a live data capture to catch intermittent signal loss.

Step 6 – Post-repair testing

• After any repair or replacement, clear codes and attempt to start; confirm that P0335 does not return.
• If the vehicle runs, monitor for any reoccurrence of CKP-related codes during driving, especially during high-load or temperature fluctuations.

Notes:

• Some Ford vehicles may benefit from a crankshaft position relearn procedure after CKP sensor replacement or timing component service. If your Ford toolset supports it, consult the service procedure for a CKP relearn or adaptation. If you do not have access to Ford-specific diagnostic software, this step may require dealer service.
• If you are not comfortable with electrical wiring and interpreting waveform data, or if the vehicle is a no-start, consider professional service.

5. RELATED CODES

• P0330 – Crankshaft Position Sensor A Circuit Malfunction (loss of signal or erratic signal)
• P0336 – Crankshaft Position Sensor A Circuit Range/Performance
• P0337 – Crankshaft Position Sensor A Circuit Low Frequency
• P0338 – Crankshaft Position Sensor A Circuit High Frequency
• P0339 – Crankshaft Position Sensor A Circuit Intermittent/Erratic
• P0340 – Camshaft Position Sensor A Circuit Malfunction (often checked alongside CKP issues for overall timing signal integrity)
• Note: On Ford vehicles, CKP issues can co-occur with CMP (camshaft) faults or wiring issues in the same harness region.

6. REPAIR OPTIONS AND COSTS (2025 PRICES)
   Prices vary by region, labor rates, and whether you use OEM or aftermarket parts. The figures below are general ranges you can expect for 2021–2024 Ford F-150 in many U.S. markets.

• Crankshaft Position Sensor (CKP) replacement (sensor only)

  • Parts: $20–$120
  • Labor: 0.5–1.5 hours
  • Typical total: $100–$300

• CKP sensor wiring/connector repair (harness repair or connector replacement)

  • Parts: $10–$60 for a repair harness segment or connector; more if wiring harness pigtails need replacement
  • Labor: 1.0–2.5 hours
  • Typical total: $150–$600

• Full CKP sensor and related harness inspection (if you suspect multiple issues)

  • Parts: Varies (sensor + possible harness)
  • Labor: 1.0–3.0 hours
  • Typical total: $180–$900

• If timing components or reluctor ring are damaged (rare but possible)

  • Parts: Several hundred dollars
  • Labor: 3.0–6.0 hours or more
  • Typical total: $700–$2,500+

Notes:

• These costs assume common retail pricing and standard labor rates. dealer prices or OEM parts can push costs higher.
• If a dealership tool or software-based CKP relearn is required, expect additional diagnostic time and potential shop fees.

7. DIY VS PROFESSIONAL
   DIY-friendly considerations:

• If you have basic automotive electrical skills, a digital multimeter, and a service manual, you can perform the checksum steps (visual inspection, basic resistance/continuity checks, connector cleaning, and CKP sensor replacement).
• You will need access to a waveform-capable tool (oscilloscope or a high-end scan tool) to definitively verify signal presence and waveform quality.
• Safety first: disconnect the battery before sensor replacement; avoid short circuits; ensure the engine is cool.

Professional considerations:

• A no-start condition with P0335 can require advanced diagnostic steps, including oscilloscope waveform capture and possible PCM data interpretation. A professional with Ford IDS/OF-Tool can perform CKP relearns if required and confirm whether PCM or wiring faults exist beyond the sensor.
• If the CKP wiring harness runs near heat sources or moving parts, the pro can perform harness routing checks and non-destructive teardown to locate hidden faults.

8. PREVENTION

• Regular electrical system checks: keep battery voltage healthy and all grounds clean and tight.
• Protect CKP wiring: use loom protection and ensure the harness is secured away from belts, pulleys, and heat sources. Avoid hard bending or pinching the harness near the sensor.
• Inspect sensor and connector during major service or timing belt/chain work; reseat and torque sensor to spec if service requires removal.
• Use high-quality replacement parts: OEM or high-quality aftermarket CKP sensors and connectors to reduce risk of premature failure.
• Address oil leaks promptly: oil or coolant leaks near the sensor can contaminate the connector; resolve leaks to maintain signal integrity.
• If you’ve recently had engine work, especially around the timing cover or harmonic balancer area, recheck CKP sensor alignment and re-test the circuit to ensure no misalignment or loose connections.

Data transparency and limitations

• The guidance above is based on the provided data: there are no NHTSA complaints or recalls listed for 2021–2024 Ford F-150 related to P0335. The diagnostic and repair guidance is therefore generalized and built on standard OBD-II CKP sensor troubleshooting practices, applicable to many Ford engines. Always cross-check with Ford’s official service literature for model-year-specific procedures and torque specs, and consider professional diagnostics if the vehicle is under warranty or if you encounter complicated electrical faults.