P0025 on 2015-2018 Lincoln MKX: Exhaust Cam Timing Causes and Fixes

What's Unique About the 2015-2018 Lincoln MKX

The Lincoln MKX's V6 engines (both 3.7L and 2.7L) are known to be sensitive to oil quality and maintenance schedules, as highlighted by manufacturer technical service bulletins. TSBs specifically mention that debris in the oil can cause the Variable Camshaft Timing (VCT) solenoids to stick, triggering codes like P0025. 🎬 Watch: How VCT solenoids fail and Ford's official service memo. Unlike some other vehicles where VCT solenoids are easily accessible, on both the 3.7L and 2.7L engines in the MKX, the solenoids are located under the valve covers, making replacement a more involved job that requires extra labor and the replacement of the valve cover gasket.

Diagnostic Flowchart

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

Generation note: The 2015 model year is the final year of the first-generation MKX, which came with the 3.7L V6 engine. The 2016-2018 models are the second generation and were available with either the standard 3.7L V6 or an optional 2.7L EcoBoost V6. The cause and diagnosis for P0025 are similar for all engines, but part numbers and specific procedures will differ slightly.

Symptoms You May Notice

• Illuminated Check Engine Light
• Rough or unstable engine idle
• Reduced engine power and hesitation during acceleration
• Decreased fuel economy
• Engine may be hard to start
• Engine stalling at low speeds or when stopping
• Engine shudder or misfire feeling, especially under load

Most Likely Causes

1. Low, Dirty, or Incorrect Viscosity Engine Oil 🔴 High Probability The VCT system is entirely hydraulic and relies on clean oil at the correct pressure. TSB SSM 50067 directly states that small debris in the oil can cause the VCT solenoid to stick, which is a primary trigger for this code. Forum users on platforms like the Ford Edge Forum have confirmed that sludgy oil and clogged solenoid screens were the direct cause of multiple VCT codes.
   How to confirm: Check the engine oil dipstick. If the oil is below the minimum level, looks very dark/sludgy, or it has been a long time since the last oil change, this is the most likely cause.
   Typical fix: Perform an engine oil and filter change using the OEM-specified full synthetic oil (such as Motorcraft 5W-20 for the 3.7L or 5W-30 for the 2.7L, always check owner's manual) and a quality filter like the Motorcraft FL-500S. Clear the code and test drive.
   Est. part cost: $50-$100
2. Failing Bank 2 Exhaust VCT Solenoid 🔴 High Probability → Shop Engine Variable Valve Timing (VVT) Solenoid This is the most common component failure for P0025. The solenoid gets clogged with debris or fails electrically, preventing it from properly regulating oil flow to the cam phaser. This is a well-documented issue across many Ford/Lincoln vehicles using the Cyclone and EcoBoost V6 engine families.
   How to confirm: Use a scan tool to monitor commanded vs. actual cam position for Bank 2 Exhaust (e.g., VCT_EXH_CMD2 vs VCT_EXH_ACT2). A large and persistent error value indicates a problem. A bidirectional scan tool can be used to cycle the solenoid as per TSB SSM 50067 to see if it responds. If an oil change doesn't fix the code, this is the next logical step.
   Typical fix: Replace the Bank 2 (front bank) exhaust VCT solenoid. Since this requires removing the valve cover, the valve cover gasket and spark plug tube seals should be replaced at the same time.
   Est. part cost: $40-$100
3. Damaged Wiring or Connector for VCT Solenoid ⚪ Low Probability → Shop Engine Variable Valve Timing (VVT) Solenoid
   How to confirm: Visually inspect the wiring harness leading to the Bank 2 valve cover for chafing or damage. Once the valve cover is removed, inspect the connector at the solenoid for oil saturation, corrosion, or broken wires.
   Typical fix: Repair the damaged section of the wiring harness or replace the pigtail connector.
   Est. part cost: $15-$50

Rare But Worth Checking

• Failing Camshaft Phaser: → Shop Engine Camshaft This is the mechanical gear that the solenoid controls. It's a more expensive and labor-intensive repair. This is usually suspected if a rattling or ticking noise is present from the front of the engine, especially on startup, and replacing the solenoid does not fix the code. Ford refers to these as 'phasers' rather than actuators.
• Stretched Timing Chain or Worn Guides: → Shop Engine Timing Chain While possible, this would typically cause multiple timing-related codes on both banks, not just P0025 in isolation. A user on a Ford Edge forum with a 2.7L EcoBoost reported that codes P0019 and P0025 were ultimately caused by a stretched timing chain after VCT solenoid replacement did not solve the issue. This is a major mechanical failure requiring significant engine work.

Diagnosis Steps

1. Verify the code with a quality OBD-II scanner.
2. Check the engine oil level and condition. If low, dirty, or past its service interval, perform an oil and filter change with the correct OEM-spec oil. This is the most important and cost-effective first step.
3. Use a scan tool with live data to monitor the PIDs for commanded vs. actual camshaft position for Bank 2 Exhaust (e.g., VCT_EXH_CMD2 vs VCT_EXH_ACT2). A large, persistent error value confirms the timing deviation.
4. As recommended by TSB SSM 50067, use a bidirectional scan tool to command the solenoid on and off (Pinpoint Test HK12). This test can determine if the solenoid is stuck or slow to respond and may even clear minor debris, temporarily resolving the issue.
5. If the oil is clean and the code persists after attempting to cycle the solenoid, the next step is to replace the Bank 2 exhaust VCT solenoid. This involves removing the front valve cover.
6. While the valve cover is off, inspect the wiring to the solenoid for any signs of damage, oil saturation, or brittleness.
7. If a new solenoid does not resolve the issue, the problem is likely mechanical. Investigate the camshaft phaser for rattling noises or signs of failure. A more advanced diagnosis, including checking timing chain stretch and engine oil pressure, would be required.

Parts You'll Likely Need

• Variable Camshaft Timing (VCT) Solenoid (OEM #3.7L: AT4Z-6M280-A; 2.7L: FT4Z-6M280-C) — This is the most common failed component for code P0025, often getting stuck due to oil debris. AT4Z-6M280-A is for the 3.7L V6. FT4Z-6M280-C was superseded by FT4Z-6M280-D for the 2.7L V6.
  Trusted brands: Motorcraft, Dorman, Standard Motor Products (SMP)
  OEM price range: $60-$100
  Aftermarket price range: $30-$70
• Valve Cover Gasket Kit (OEM #3.7L: 7T4Z-6584-A (Left/Front Bank); 2.7L: FT4Z-6584-A (Right/Front Bank)) — Replacement is required to access the VCT solenoids on both the 3.7L and 2.7L engines. The kit should include the main gasket and spark plug tube seals. For the 3.7L, the front (Bank 2) gasket is part 7T4Z-6584-A. For the 2.7L, the front (Bank 2) gasket is part FT4Z-6584-A.
  Trusted brands: Motorcraft, Fel-Pro, Mahle
  OEM price range: $50-$90
  Aftermarket price range: $30-$60
• Engine Oil and Filter (OEM #Filter: FL-500S (for both engines)) — Low or dirty oil is a primary cause. An oil change is the first diagnostic step and is recommended even when replacing the solenoid.
  Trusted brands: Motorcraft, Mobil 1, Castrol
  OEM price range: $50-$80
  Aftermarket price range: $40-$70

Related Codes That Often Appear With This One

• P0019 — This is a Crankshaft-Camshaft Correlation code for Bank 2, Exhaust Cam. An over-retarded cam (P0025) will naturally cause a correlation error with the crankshaft. Seeing these two codes together strongly points to a fault in the Bank 2 exhaust VCT system.
• P0024 — This code is for an over-advanced condition on the same camshaft. Seeing both can indicate a VCT solenoid that is sticking intermittently in both directions or has a severe hydraulic blockage.
• P0016, P0017, P0018 — These are other camshaft/crankshaft correlation codes. If they appear alongside P0025, it may indicate a more widespread timing issue, such as a stretched timing chain or severe oil pressure/quality problems affecting multiple components.

Technical Service Bulletins (TSBs) & Recalls

• SSM 50067 - Illuminated MIL with various VCT DTCs due to debris causing solenoid to stick.
• SSM 54366 - Updated diagnostic procedures for VCT-related DTCs

Platform-Specific Known Issues

• TSB SSM 50067: Notes that DTCs including P0025 may be caused by small debris causing the VCT solenoid to stick. It advises against immediate component replacement, instead recommending technicians first use a scan tool to cycle the solenoid 10 times (Pinpoint Test HK12) to attempt to clear the debris.
• TSB SSM 54366: Mentions an update to the official workshop manual's diagnostic procedure (Pinpoint test HK) for a group of VCT codes including P0025, indicating this is a well-documented and evolving issue for technicians. [TSB]

Mechanic-Grade Diagnostic Values

• VCT Solenoid Internal Resistance — expected: 5.0 to 14.0 Ohms. A tighter specification is 6.9 to 7.9 Ohms at 68°F (20°C).. Failure: A reading of 0 Ohms (short circuit) or infinite/OL (open circuit) indicates a failed solenoid coil.
• Engine Oil Pressure at Idle (Hot) — expected: Minimum of 15-25 PSI.. Failure: Pressure below 15 PSI can cause insufficient hydraulic force for the VCT phasers to operate correctly, leading to timing codes.
• Ford IDS Live Data PID: VCT_EXH_ERR2 (VCT Exhaust Error Bank 2) — expected: Should hover close to 0° with a tolerance of +/- 5° during stable engine operation.. Failure: A large, persistent positive or negative value indicates the camshaft is not at its commanded position, confirming a fault in the VCT system for that specific camshaft.
• VCT Solenoid Connector Voltage (Key On, Engine Off) — expected: Greater than 10.5 V on the power supply pin.. Failure: Voltage below this level suggests a problem in the power feed circuit (wiring, fuse, or PCM driver) rather than the solenoid itself.

Hidden / Shadow Codes Worth Checking

• Mode $06, Test ID $53 (TID 53): This test monitor in the generic OBD-II data relates to Variable Camshaft Timing (VCT) system monitoring. It tracks the error between the commanded and actual position of the camshafts. (see via A professional scan tool or an advanced OBD-II app (like FORScan) that can access Mode $06 data. On CAN-compliant vehicles, the data is easier to interpret and does not require conversion factors.)

Scan Tool Commands That Help

• Ford IDS (Integrated Diagnostic System) or FORScan: VCT Solenoid On/Off Cycle Test (Output State Control) — This is a critical bidirectional test mentioned in TSBs SSM 50067 and 47170. It allows the technician to command the VCT solenoid on and off repeatedly (typically 10 times) to see if it is mechanically stuck. A change in engine idle and an audible click from the solenoid indicate it is responding. This test can sometimes dislodge minor debris and temporarily fix the issue, which confirms a sticking solenoid is the root cause.

Wiring & Ground Locations

• Bank 2 VCT Solenoid Connector — Under the front (radiator side) valve cover, connected to the exhaust VCT solenoid.. The connector itself can become brittle from heat cycles or contaminated with oil if the valve cover gasket fails, leading to a poor connection and symptoms identical to a failed solenoid.
• Engine Ground Strap (Firewall to Cylinder Head) — There is a primary ground strap that typically runs from the firewall (bulkhead) to a stud on the back of the driver's side cylinder head (Bank 2 on a 3.7L).. A poor or corroded engine ground can cause electrical noise and voltage discrepancies for all engine sensors, including the Camshaft Position Sensors. This can lead to inaccurate readings and potentially trigger timing correlation codes, even if the mechanical timing is correct. One owner with multiple cam/crank codes traced the issue to a bad ground.
• Engine Ground (Motor Mount) — An additional ground point is often located on or near the passenger side motor mount as part of the main engine harness.. This serves as another critical ground path for the engine block and its associated sensors. Ensuring this connection is clean and tight is essential for stable sensor operation.

Real Owner Repair Stories

• Ford Edge Forum (2016 Ford Edge Sport 2.7L EcoBoost (mechanically similar to Lincoln MKX)) — Check engine light with codes P0019 and P0025.
  ❌ Tried (didn't work) Replacing the VCT solenoids.
  ✅ What actually fixed it The ultimate cause was a stretched timing chain. The repair involved replacing the timing chain, guides, and tensioners, which resolved both codes.

OEM Part Supersession History

• AT4Z-6M280-A → AT4Z-6M280-B — Part revision/update by Ford.
  Heads up: AT4Z-6M280-B is the common replacement for the 3.7L V6 VCT solenoids and is often used for both intake and exhaust positions.
• FT4Z-6M280-A / FT4Z-6M280-B / FT4Z-6M280-C → FT4Z-6M280-D — Multiple part revisions by Ford for the 2.7L EcoBoost VCT solenoids.
  Heads up: Always verify the latest part number with a VIN, as there have been several updates for the 2.7L engine's solenoids.