P0018 on 2015-2018 Lincoln MKX: Crankshaft-Camshaft Correlation Causes and Fixes

What's Unique About the 2015-2018 Lincoln MKX

For this generation of Lincoln MKX, Ford has issued multiple Technical Service Bulletins (TSBs) highlighting that P0018 and related codes are often caused by small debris in the engine oil, which makes the Variable Camshaft Timing (VCT) solenoids stick. [SSM 48423, SSM 50067, SSM 47170] TSBs SSM 48423 and 50067 specifically advise technicians to use a scan tool to cycle the affected VCT solenoid 10 times to attempt to clear the debris before attempting component replacement. This suggests the problem is frequently related to oil quality and the VCT system's sensitivity rather than an immediate sensor or mechanical failure. 🎬 Watch: Understanding the causes and fixes for the P0018 code. Additionally, the naturally-aspirated 3.7L V6 engine features an internal, timing-chain-driven water pump; a failure of this pump can contaminate the engine oil with coolant, leading to widespread timing system problems, including this code.

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 was the last of the first-generation MKX, while 2016-2018 models are the second generation. The primary difference regarding this code lies in the available engines. The 3.7L V6 was available across these years, but the 2.7L EcoBoost V6 was introduced with the second generation in 2016. Both engines are susceptible to VCT solenoid issues, but the 3.7L has a well-documented history of timing chain and internal water pump issues that can also trigger this code. The 2.7L EcoBoost, while also prone to timing chain stretch at high mileage, does not share the internal water pump design.

Symptoms You May Notice

• Check Engine Light is on
• Rough or unstable idle
• Engine stalling, especially when coming to a stop
• Reduced engine power and poor acceleration
• Decreased fuel economy
• Rattling noise from the engine, particularly on startup (a key indicator of timing chain tensioner or phaser issues)

Most Likely Causes

1. Low, Dirty, or Incorrect Viscosity Engine Oil 🔴 High Probability The VCT system is hydraulically operated and highly sensitive to oil pressure and cleanliness. The TSBs citing debris in the oil as a cause for sticking solenoids underscore this sensitivity. [SSM 48423, 1]
   How to confirm: Check the engine oil level on the dipstick and inspect its condition. If it's low, dark, or appears contaminated, this is a likely contributor. Ensure the oil viscosity matches the OEM specification (SAE 5W-30 for both the 3.7L and 2.7L EcoBoost).
   Typical fix: Perform a complete engine oil and filter change using a high-quality, full synthetic engine oil meeting the correct OEM specifications and a new filter.
   Est. part cost: $50-$100
2. Sticking or Failed Variable Camshaft Timing (VCT) Solenoid 🔴 High Probability → Shop Engine Camshaft Multiple TSBs (SSM 54366, SSM 48423, SSM 50067, SSM 47170) directly state that sticking VCT solenoids due to small debris are a common cause for this code on these vehicles. This is the most common point of failure before the timing chain itself.
   How to confirm: A technician can use a scan tool to command the solenoid on and off to check for response, as per TSB SSM 48423. A common DIY method is to swap the Bank 2 intake solenoid with the Bank 1 intake solenoid; if the code changes to P0016, the solenoid is confirmed as faulty. On the 2.7L EcoBoost, the VCT solenoids can often be accessed and replaced without removing the valve cover.
   Typical fix: Replace the Bank 2 intake VCT solenoid. It is often recommended to replace them in pairs (intake and exhaust) or all four at once. An oil change should be performed at the same time.
   Est. part cost: $40-$120
3. Stretched Timing Chain or Worn Timing Components 🟡 Medium Probability → Shop Engine Timing Chain The 3.7L V6 engine, in particular, is known for timing chain stretch at higher mileage. This can be accelerated by a failing internal water pump leaking coolant into the oil, which degrades the plastic chain guides and tensioners. The 2.7L EcoBoost can also suffer from stretched chains, though it's a different design.
   How to confirm: This is a complex diagnosis. After ruling out oil and VCT issues, a mechanic must check for slack and verify timing marks, which requires partial engine disassembly. A persistent startup rattle is a strong indicator. Labor for this job on a 3.7L can be 14-18 hours.
   Typical fix: Replace the timing chain, tensioners, guides, and phasers. On the 3.7L engine, the water pump should always be replaced at the same time. This is a very expensive repair, often exceeding $2,000.
   Est. part cost: $400-$800
4. Failed Camshaft or Crankshaft Position Sensor ⚪ Low Probability → Shop Engine Crankshaft Position Sensor While sensors can fail, it is far less common than the mechanical and hydraulic issues noted above for this specific code on this platform. Misdiagnosing this as a bad sensor is a common mistake.
   How to confirm: A multimeter can be used to test the sensor's wiring for power and ground. A scan tool can monitor the sensor's live data for erratic signals or dropouts.
   Typical fix: Replace the faulty sensor. The Bank 2 sensor is located on the front valve cover.
   Est. part cost: $30-$80

Rare But Worth Checking

• Damaged Camshaft Phaser: → Shop Engine Camshaft The phaser itself can fail mechanically or become clogged with debris, preventing it from adjusting cam timing correctly. This is usually replaced during a timing chain service. A failure can also be caused by incorrect installation during a previous repair.
• Wiring Harness Damage: Damage or corrosion on the wiring or connectors for the VCT solenoid or camshaft position sensor can cause an intermittent signal and trigger the code. A wiggle test on the harness while monitoring sensor data can help identify this.
• Low Oil Pressure: Beyond just low oil level, a failing oil pump or clogged oil passages can starve the VCT system of the pressure it needs to operate, causing correlation codes. An oil pressure test is needed to confirm this. Hot idle pressure should be at least 25 PSI.
• Faulty Powertrain Control Module (PCM): → Shop Engine Control Module (ECM) In very rare cases, the PCM itself may have a faulty driver circuit or logic error, causing it to misinterpret sensor data. This should only be considered after all other possibilities are exhausted.

Diagnosis Steps

1. Check the engine oil level and condition. Top up or perform an oil and filter change if necessary, using the manufacturer-specified full synthetic oil.
2. Use an OBD-II scanner to confirm P0018 is present and check for any other related codes. Review freeze frame data to see the engine conditions when the code was set.
3. Inspect the wiring and connectors for the Bank 2 camshaft position sensor and VCT solenoid for any visible damage, corrosion, or loose connections.
4. Using a capable scan tool (like FORScan), monitor the live data PIDs for desired vs. actual camshaft position on Bank 2 (e.g., VCT_INT_ANG2 vs VCT_INT_DIF2) to see the discrepancy in real-time.
5. As per Ford TSB SSM 48423, command the Bank 2 intake VCT solenoid on and off with the scan tool 10 times to attempt to dislodge debris. Listen for an audible click and watch for a change in engine performance or live data.
6. If the solenoid is suspected, swap the Bank 2 intake VCT solenoid with the Bank 1 intake solenoid. Clear the codes and drive the vehicle. If the code changes to P0016, the solenoid is faulty and must be replaced.
7. If solenoids and sensors test good, perform an engine oil pressure test to ensure it's within specification, especially at hot idle.
8. If all else fails, a physical inspection of the timing chain, guides, and tensioners is required. This is a labor-intensive step to check for stretch or damage and should be performed by a professional.

Parts You'll Likely Need

• Engine Variable Valve Timing (VVT) Solenoid / VCT Solenoid (OEM #AT4Z-6M280-B (For 3.7L) / FT4Z-6M280-B (For 2.7L, supersedes FT4Z-6M280-A)) — This is the most common point of failure according to multiple TSBs, often due to sticking from oil debris. [SSM 50067, 4, 18]
  Trusted brands: Motorcraft, Dorman, Standard Motor Products (SMP), Gates
  OEM price range: $50-$90
  Aftermarket price range: $30-$60
• Timing Chain Kit (OEM #AT4Z-6268-C (Primary chain for 3.7L, example)) — Required if the timing chain is stretched or if guides are broken. For the 3.7L, this job must include the internal water pump.
  Trusted brands: Motorcraft, Cloyes, Melling
  OEM price range: $400-$800
  Aftermarket price range: $250-$500
• Engine Oil and Filter — Crucial first step and required maintenance. Using the correct full synthetic oil (SAE 5W-30) and a quality filter is essential for VCT system health.
  Trusted brands: Motorcraft Synthetic Blend, Pennzoil Platinum, Mobil 1
  OEM price range: $50-$100
  Aftermarket price range: $40-$80

Related Codes That Often Appear With This One

• P0016 — Crankshaft/Camshaft Correlation error on Bank 1. If both P0016 and P0018 are present, it strongly points towards a base timing issue like a stretched primary timing chain or an issue with the crankshaft reluctor wheel.
• P0017 — Crankshaft/Camshaft Correlation error for the exhaust camshaft on Bank 1. Often appears with other timing codes.
• P0019 — Crankshaft/Camshaft Correlation error for the exhaust camshaft on Bank 2. If this appears with P0018, it could indicate an issue with both VCT solenoids on Bank 2 or a larger timing problem affecting the entire bank.
• P0021 — Intake Camshaft Position Timing - Over-Advanced (Bank 2). This code often accompanies P0018 and points directly to a problem with the VCT solenoid or phaser for the Bank 2 intake cam.

Technical Service Bulletins (TSBs) & Recalls

• SSM 54366: Notes P0018 among other codes and refers to specific diagnostic tests.
• SSM 50067: States P0018 may be due to small debris causing the VCT solenoid to stick.
• SSM 48423: Also attributes P0018 to a sticking VCT solenoid caused by debris.
• SSM 47170: An earlier bulletin with the same diagnosis of a sticking VCT solenoid from debris.

Platform-Specific Known Issues

• Risk of Incorrect Timing During Major Repairs: As documented in forums for platform mates like the F-150, receiving a P0018 code immediately after a timing chain or cam phaser replacement is a strong indication that the base mechanical timing was set incorrectly. This highlights the critical need for precision during such repairs and is a common pitfall for both DIYers and inexperienced technicians.
• 3.7L Internal Water Pump Failure: → Shop Engine Water Pump A unique and significant failure point for the 3.7L V6 is the internal, timing-chain-driven water pump. When its bearing or seal fails, it leaks coolant directly into the crankcase, contaminating the engine oil. This contaminated oil quickly damages VCT solenoids, phasers, and plastic timing chain guides, leading to codes like P0018 and eventual catastrophic failure if not addressed. When performing a timing chain replacement on the 3.7L, replacing the water pump is considered mandatory preventative maintenance.

Mechanic-Grade Diagnostic Values

• VCT Solenoid Internal Resistance — expected: 5.0 - 14.0 Ohms. Failure: A reading outside this range, or infinite resistance (open circuit), indicates a failed solenoid coil.
• VCT Solenoid Power Supply Voltage — expected: > 10.5 Volts (with Key On, Engine Off). Failure: Voltage below 10.5V points to an open circuit or issue in the power feed wiring to the solenoid.
• Engine Oil Pressure (at hot idle) — expected: Minimum 25 PSI. Failure: Pressure below 25 PSI indicates oil starvation that will prevent the VCT system from operating correctly.
• 3-Wire Camshaft Position Sensor (CMP) Voltage Check — expected: One wire should have ~5V (power), one should have near 0V (ground), and the third is the signal wire.. Failure: Missing power or ground indicates a wiring or PCM issue. The signal wire should produce a fluctuating voltage when the engine is cranked.

Hidden / Shadow Codes Worth Checking

• Mode 6, Test ID $82: This is Ford's on-board diagnostic monitor for VCT position. It stores statistical data on cam timing performance. A failure logged here can indicate a developing problem with the VCT system even before a Check Engine Light and a P-code are triggered. (see via A scan tool capable of reading Mode 6 data, such as the Ford IDS or advanced consumer tools like FORScan.)
• CMDTCs (Continuous Memory Diagnostic Trouble Codes): This is a more thorough code retrieval function than a standard scan. It can reveal intermittent or pending codes that have been stored in the PCM's memory but have not yet met the criteria to illuminate the MIL. (see via Ford's Integrated Diagnostic System (IDS) or equivalent professional scan tool.)

Scan Tool Commands That Help

• Ford IDS / FORScan: VCT Solenoid On/Off Test (Pinpoint Test HK) — As per TSBs, this command cycles the solenoid rapidly (typically 10 times) to dislodge small debris. If the code clears or engine behavior changes, it confirms a sticking solenoid, potentially avoiding an immediate replacement.
• Ford IDS / FORScan: Monitor PIDs: RCAM_ERR / CAM_ERR — These PIDs show the live difference (in degrees) between the PCM's desired camshaft angle and the actual angle reported by the sensor. A large, persistent error value while driving confirms a real-time correlation fault and helps rule out intermittent sensor glitches.
• Ford IDS / FORScan: KOER (Key On, Engine Running) Self-Test — This automated test commands the PCM to cycle various actuators, including the VCT solenoids. It can be used to verify that the PCM is capable of sending the command signal to the solenoid, helping to differentiate between a wiring/PCM issue and a mechanical solenoid failure.

Wiring & Ground Locations

• Bank 2 VCT Solenoid Connector — On the front of the Bank 2 valve cover. Bank 2 is the cylinder bank closer to the radiator on the transverse V6 engines.. This is the direct electrical connection to the most likely failed component. Damage, corrosion, or oil contamination in this 3-wire connector can mimic a failed solenoid, leading to a misdiagnosis.
• Engine Ground Points (e.g., G104) — Various points on the engine block, chassis, and near the firewall. An official wiring diagram is required for exact locations.. A poor or corroded engine ground can introduce electrical noise into sensor circuits, potentially causing the PCM to receive incorrect data from the cam and crank sensors, leading to false correlation codes.

OEM Part Supersession History

• N/A → AT4Z-6M280-B — This is the OEM part number for the Bank 2 (radiator side) INTAKE VCT solenoid, which is the specific part implicated by code P0018.
• N/A → AT4Z-6M280-A — This part number fits the Bank 2 EXHAUST position and the Bank 1 INTAKE position. It is not the correct part for a P0018 code.
  Heads up: Do not use this part for P0018; it controls the wrong camshaft.
• 3L3Z-6M280-EA, 8L3Z-6M280-A → 8L3Z-6M280-B — This is a common VCT solenoid for Ford V8 engines (4.6L/5.4L 3-Valve).
  Heads up: CRITICAL: This part (8L3Z-6M280-B) is often confused online but is for V8 engines and WILL NOT work in the 3.7L or 2.7L V6 engines in the Lincoln MKX.

Model Year Variations Within This Range

• 2016-2018: The optional 2.7L EcoBoost V6 engine has a significantly more complex timing chain installation procedure than the 3.7L V6. It involves multiple 360-degree crank rotations between setting the timing on each bank. An error during this procedure can easily cause correlation codes like P0018 immediately after a timing job.