P0340 on 2013-2017 Ford Fusion Hybrid: Oil Moisture, Sensor Failure, and Fixes

What's Unique About the 2013-2017 Ford FUSION HYBRID

What makes the Fusion Hybrid unique regarding code P0340 is its susceptibility to oil contamination from specific driving habits. Because the hybrid system prioritizes electric motor use at low speeds, the gasoline engine often runs for short periods, failing to reach and maintain full operating temperature. Ford issued Technical Service Bulletin (TSB) #SSM 48598 because these hybrids, when driven only for short distances (less than 6,000 miles per year), may not run the gasoline engine long enough to burn off natural condensation. This leads to excessive moisture in the oil, which can appear as a milky or creamy residue under the oil cap and can interfere with the camshaft sensor's operation, triggering a P0340 code. This issue is far less common on their non-hybrid counterparts with different driving patterns.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light is on
• Engine is hard to start or cranks but won't start
• Engine stalls or stops while driving
• Rough idling
• Loss of engine power and poor acceleration
• Engine dies and refuses to restart.

Most Likely Causes

1. Excessive Moisture in Engine Oil 🔴 High Probability As a hybrid, the gasoline engine often runs for short periods, which is not enough to heat the oil sufficiently to evaporate condensation. Ford TSB #SSM 48598 directly addresses this for the Fusion Hybrid, C-Max Hybrid, and Lincoln MKZ Hybrid.
   How to confirm: Check the underside of the oil filler cap and the dipstick for a milky, frothy, or creamy-brown residue, which indicates 🎬 Watch: See what this milky oil residue looks like. water/condensation in the oil. This is a very common sign discussed by owners in forums.
   Typical fix: Perform an engine oil and filter change. The TSB also recommends replacing the camshaft position sensor at the same time. Advise the owner to ensure the vehicle is driven long enough for the engine to reach full operating temperature more frequently.
   Est. part cost: $50-$100 for oil and filter
2. Failed Camshaft Position (CMP) Sensor 🟡 Medium Probability → Shop Engine Camshaft Position Sensor The sensor itself can fail electronically over time. The TSB-recommended fix includes replacing the sensor along with the oil change, suggesting the contaminated oil may damage the sensor or interfere with its magnetic signal.
   How to confirm: After confirming oil quality is good and wiring is intact, replacing the sensor is the next logical step. Testing with a multimeter is possible but often inconclusive for intermittent failures. 🎬 Watch: How to diagnose and fix a P0340 code.
   Typical fix: Replace the camshaft position sensor. A DIY video shows this is an accessible part on top of the engine.
   Est. part cost: $30-$75
3. Wiring or Connector Issue ⚪ Low Probability
   How to confirm: Visually inspect the wiring harness and connector leading to the camshaft position sensor for any signs of damage, corrosion, or loose pins.
   Typical fix: Repair the damaged section of wiring or clean/replace the connector.
   Est. part cost: $5-$50

Rare But Worth Checking

• Failing Powertrain Control Module (PCM): → Shop Engine Control Module (ECM) This is very rare. Before condemning the PCM, all other possibilities, including wiring, sensors, and the oil condition, must be exhaustively ruled out.
• Timing Chain/Belt Issues: → Shop Engine Timing Chain While a stretched or jumped timing chain can cause cam/crank correlation issues, it's less common for this specific code and would likely be accompanied by other codes (like P0016) or significant engine noise. One Reddit user was quoted $5,000 for a timing chain issue that was initially misdiagnosed from a P0340 code.

Diagnosis Steps

1. Scan for trouble codes. Confirm P0340 is present and check for any other codes, especially P0344.
2. Inspect the engine oil. Turn the engine off, remove the oil filler cap, and check for a milky or frothy residue. Pull the dipstick and check the oil's condition and level.
3. If oil is contaminated, perform an engine oil and filter change. Per Ford TSB #SSM 48598 (and its successors), it is also recommended to replace the camshaft position sensor at this time.
4. If oil appears clean, inspect the camshaft position sensor's electrical connector and wiring. Look for any breaks, corrosion, or loose connections.
5. If wiring is okay, replace the camshaft position sensor. It is located on the top of the valve cover and is held by a single 8mm bolt.
🎬 See this walkthrough for locating and replacing the sensor.
6. Clear the trouble codes with a scanner and perform a test drive, ensuring the gasoline engine runs long enough to reach full operating temperature to burn off any residual moisture.
7. If the code returns, a more in-depth diagnosis of the wiring circuit or, in very rare cases, the PCM may be required.

Parts You'll Likely Need

• Camshaft Position Sensor (OEM #DG9Z-6C315-B) — This sensor is the primary component identified by the code and is often damaged or has its signal impeded by the oil moisture issue described in the TSB.
  Trusted brands: Motorcraft, Denso (OEM manufacturer), Bosch, Carquest Premium
  OEM price range: $40-$75
  Aftermarket price range: $19-$50.
• Engine Oil and Filter — Required to fix the root cause of moisture contamination as specified in TSB #SSM 48598.
  Trusted brands: Motorcraft
  OEM price range: $50-$80
  Aftermarket price range: $40-$60

Related Codes That Often Appear With This One

• P0344 — P0344 is 'Camshaft Position Sensor 'A' Circuit Intermittent'. Both P0340 and P0344 are mentioned together in TSB #SSM 48598 as resulting from the same oil moisture issue.
• P1A0C — P1A0C is 'Hybrid Powertrain Control Module - Engine Disabled'. This code can appear alongside P0340, as the hybrid control module may disable the gasoline engine if it cannot get a reliable camshaft position signal. A Reddit user reported this combination on their 2013 Fusion Hybrid.

Technical Service Bulletins (TSBs) & Recalls

• SSM 48598: Addresses P0340/P0344 caused by oil moisture from short trips, recommending a CMP sensor replacement and oil change. This TSB applies to the Fusion Hybrid, C-Max Hybrid, and MKZ Hybrid.

Platform-Specific Known Issues

• TSB #SSM 48598: Ford has identified that 2013-2020 Fusion Hybrids may exhibit DTC P0340 and/or P0344 due to excessive moisture buildup in the engine oil from short-distance driving. The official fix is to replace the camshaft position sensor and change the engine oil.
• Owner Experience: Sensor Replacement Alone is Not Enough: NHTSA complaint #11191466 for a 2015 Fusion details a scenario where the check engine light with code P0340 returned just 1,708 miles after the camshaft position sensor was replaced. This highlights the importance of also changing the contaminated oil, as recommended by the TSB, to fully resolve the root cause.
• Real-World Repair Story: A YouTube video by a 2014 Fusion Hybrid owner demonstrates the classic symptoms: codes P0340/P0344 and a milky residue under the oil cap. The owner notes his daughter's commute changed to be very short, causing the issue. He states that Denso is the OEM manufacturer for the sensor and that replacing it along with an oil change is the correct fix.

Mechanic-Grade Diagnostic Values

• Camshaft Position Sensor (CMP) Power Supply Pin Voltage — expected: Approximately 5.0 volts with Key On, Engine Off (KOEO).. Failure: A reading below 4.5V or 0V points to an open or short in the reference voltage circuit from the PCM.
• Camshaft Position Sensor (CMP) Signal Voltage — expected: Using a multimeter or oscilloscope, voltage should switch rapidly between approximately 0V and 5V as the engine is cranked or running.. Failure: Voltage that is stuck high (at 5V), stuck low (at 0V), or does not switch indicates a failed sensor or a circuit problem.
• Camshaft Position Sensor (CMP) Ground Pin Resistance — expected: Less than 5 ohms of resistance between the ground pin on the connector and the negative battery terminal or a known good chassis ground.. Failure: High resistance (greater than 5 ohms) or an open circuit (OL) indicates a faulty ground connection, which can cause an incorrect sensor signal.

Scan Tool Commands That Help

• Ford IDS / FORScan / Capable Bidirectional Scanner: VCT Solenoid On/Off Command (or similar active command) — Although not directly for P0340, if the sensor and wiring are confirmed good but drivability issues persist, commanding the VCT solenoids on and off can help diagnose a sticking solenoid, which can cause erratic cam timing that might be misinterpreted. TSB SSM 50067 for related codes advises cycling the solenoid 10 times to attempt to clear debris.

Wiring & Ground Locations

• CMP Sensor Connector — On top of the valve cover, plugged directly into the camshaft position sensor.. This 3-wire connector provides the sensor with power, ground, and the path for the signal to return to the PCM. Corrosion, oil contamination, or damaged wires at this connector are a common cause of a P0340 circuit code.
• G101 — Left front of the engine compartment.. This is a primary engine bay ground point. A loose or corroded connection here can cause unstable sensor readings and various electrical faults.
• G108 / G109 — G108 is on the right rear of the engine compartment; G109 is on the rear of the engine.. These are additional engine-to-chassis ground points. The integrity of the engine's ground path is critical for all sensors, including the CMP, to provide a stable signal to the PCM.

Real Owner Repair Stories

• YouTube video by user 'Fix It Rich' (2014 Ford Fusion Hybrid 2.0L) — Check Engine Light with codes P0340 and P0344. Milky, condensation-like residue under the oil filler cap.
  ❌ Tried (didn't work) The owner correctly diagnosed the issue based on common knowledge of these hybrids and did not report trying incorrect fixes.
  ✅ What actually fixed it The owner replaced the camshaft position sensor and performed an engine oil change to resolve the issue caused by condensation from short drives. He also noted a faulty thermostat was a contributing factor and that Denso is the OEM manufacturer for the Ford sensor.
• Reddit user Zeledon3 in r/MechanicAdvice (2013 Ford Fusion Hybrid) — Check Engine Light with code P0340, rough idle, and poor mileage.
  ❌ Tried (didn't work) The owner was given a quote of approximately $5,000 by a Ford dealership mechanic for a timing chain replacement.
  ✅ What actually fixed it The quote was a mistake. The mechanic had confused the appointment with another vehicle that had a timing chain issue. The actual, much cheaper repair was implied to be the standard sensor and oil change, highlighting a common misdiagnosis.

OEM Part Supersession History

• DG9Z-6C315-B → No direct supersession found in searches. — N/A
  Heads up: The prefix (e.g., 'DG9Z') on Ford sensor part numbers is critical for correct application. While other '6C315' sensors exist, they are for different engines/vehicles. An owner confirmed that Denso is the original equipment manufacturer for the Motorcraft sensor on this vehicle, providing a reliable aftermarket alternative.

Model Year Variations Within This Range

• 2013-2017: No significant variations in the cause or fix for code P0340 were found within this model year range. The issue of oil contamination and the corresponding TSB #SSM 48598 apply across these years.