P0025 on 2015-2019 Ford Taurus: Exhaust Cam Timing Causes and Fixes

What's Unique About the 2015-2019 Ford TAURUS

The Ford 3.5L V6 engines, common in this generation of Taurus, are known for having issues with their VCT systems. Ford has issued multiple Technical Service Bulletins (TSBs) like SSM 50067 and SSM 54366, which acknowledge that small debris in the engine oil can cause the VCT solenoids to stick, leading to codes like P0025. This makes oil quality and the health of the VCT solenoid a much higher probability cause on this vehicle compared to general possibilities on other makes. The location of Bank 2 on the firewall side also makes access to the solenoid more difficult and labor-intensive, especially on EcoBoost models where the intake manifold may need to be removed.

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
• Rough or unstable idle
• Reduced engine power and acceleration
• Engine may be hard to start
• Decreased fuel economy
• Engine stalling, especially at low speeds or when stopping
• Rattling noise from the engine, particularly on startup, may indicate a more serious timing chain issue

Most Likely Causes

1. Low, Old, or Dirty Engine Oil 🔴 High Probability The VCT system is entirely dependent on clean engine oil with correct pressure to function. Ford TSBs (SSM 50067) directly cite debris in the oil as a primary cause of VCT solenoid failure for this code. Sludge can clog the fine mesh screens on the solenoids, restricting oil flow.
   How to confirm: Check the oil level on the dipstick and inspect its color and consistency. If the level is low or the oil is dark, gritty, or sludgy, this is the likely cause. This should always be the first diagnostic step.
   Typical fix: Perform an engine oil and filter change using the manufacturer-specified grade of oil (e.g., Motorcraft 5W-20 or 5W-30 depending on the engine) and a quality filter.
   Est. part cost: $40-$80
2. Faulty Bank 2 Exhaust VCT Solenoid 🔴 High Probability → Shop Engine Variable Valve Timing (VVT) Solenoid As noted in multiple Ford TSBs, these solenoids are prone to sticking or failing due to contamination from engine oil. This is the most common part to fail for this specific code. Bank 2 is the firewall side, which can make access more difficult, often requiring removal of the upper intake manifold.
   How to confirm: A mechanic can use a scan tool to command the solenoid on and off to check for a response (an audible click). Another method is to swap the exhaust solenoid with the intake solenoid on the same bank and see if the code changes to P0022 (Intake Over-Retarded). Resistance can also be checked with a multimeter and should be between 5.0 and 25.0 ohms.
   Typical fix: Replace the Bank 2 exhaust VCT solenoid. It is recommended to also change the engine oil and filter at the same time. The OEM part number is often AT4Z-6M280-C or a superseding number.
   Est. part cost: $30-$90
3. Faulty Camshaft Position Sensor (Bank 2, Exhaust) ⚪ Low Probability → Shop Engine Camshaft Position Sensor
   How to confirm: This is rarely the cause. The sensor is usually doing its job by correctly reporting the timing error. If a new VCT solenoid doesn't fix the code, the sensor that reads the camshaft's position could be faulty. This is diagnosed by checking the sensor's signal with an oscilloscope or by swapping it with a known good sensor.
   Typical fix: Replace the Bank 2 exhaust camshaft position sensor.
   Est. part cost: $25-$60

Rare But Worth Checking

• Stretched Timing Chain or Worn Cam Phaser: → Shop Engine Timing Chain This is a more serious mechanical issue that usually occurs at higher mileage (over 100,000 miles). If you hear a rattling noise from the front of the engine, especially on startup, it could indicate a problem with the timing chain or phasers. This is a much more involved and expensive repair.
• Clogged Oil Passages: In cases of severe engine sludge, the oil passages leading to the VCT solenoid and cam phaser can become blocked. Even a new solenoid won't work if oil can't get to it. This usually requires significant engine cleaning or disassembly.
• Wiring or Connector Issues: Damage to the wiring harness or a corroded connector for the VCT solenoid can interrupt the signal from the PCM, causing the code. A visual inspection of the harness, especially where it might be pinched or exposed to heat, is recommended.

Diagnosis Steps

1. Check Engine Oil: Verify the oil level is correct and the oil is clean. If low or dirty, perform an oil and filter change with the correct viscosity oil (e.g., Motorcraft 5W-20/5W-30), clear the code, and see if it returns.
2. Scan for Codes: Use an OBD-II scanner to confirm P0025 and check for any other related codes like P0019.
3. Monitor Live Data: Use a capable scan tool (like FORScan) to monitor the desired vs. actual camshaft position for Bank 2 Exhaust (PIDs: VCT_EXH2_DSD vs VCT_EXH2_ACT). A large, persistent error (PID: VCT_EXH_ERR2) indicates a problem.
4. Test the VCT Solenoid: Use the scan tool's bidirectional controls to command the Bank 2 exhaust solenoid on and off. Listen for a click and watch for a change in engine idle. TSB SSM 50067 suggests cycling the solenoid 10 times to potentially clear debris before replacement.
5. Inspect Wiring: Check the wiring and connector for the Bank 2 exhaust VCT solenoid and camshaft position sensor for any damage, corrosion, or loose connections.
6. Swap Solenoids (if possible): If accessible, swap the exhaust VCT solenoid with the intake solenoid on the same bank. Clear codes and drive the vehicle. If the code changes to P0022, the solenoid is confirmed to be faulty.
7. Measure Solenoid Resistance: Disconnect the solenoid and measure the resistance across its two pins with a multimeter. A reading between 5.0 and 25.0 ohms is typically expected. An open circuit (infinite resistance) confirms failure.
8. Inspect Mechanical Timing: If all else fails, a more in-depth mechanical inspection of the timing chain, guides, and cam phaser is required. This is best left to a professional.

Parts You'll Likely Need

• Variable Camshaft Timing (VCT) Solenoid (OEM #AT4Z-6M280-C (Bank 2 Exhaust)) — This part is the most common cause of failure for P0025 on this vehicle, as it gets stuck from oil debris. Bank 2 is the firewall side.
  Trusted brands: Motorcraft, Dorman
  OEM price range: $50-$90
  Aftermarket price range: $30-$60
• Engine Oil and Filter (OEM #Motorcraft FL-500S (Filter)) — Low or contaminated oil is a primary trigger for VCT system faults. An oil change is the first and most crucial step.
  Trusted brands: Motorcraft
  OEM price range: $40-$80
  Aftermarket price range: $40-$80
• Valve Cover Gasket — The valve cover must be removed to access the VCT solenoid, so replacing the gasket is required to prevent oil leaks upon reassembly.
  Trusted brands: Ford, Fel-Pro
  OEM price range: $30-$60
  Aftermarket price range: $20-$40

Related Codes That Often Appear With This One

• P0019 — This is a Crankshaft/Camshaft correlation code for the same bank and camshaft. TSB 16-0038 notes that if P0019 and P0025 appear together, the Bank 2 exhaust VCT solenoid should be replaced.
• P0022 — This code is for 'Intake (A) Camshaft Position - Timing Over-Retarded (Bank 2)'. If you swap the intake and exhaust solenoids on Bank 2 for diagnosis and the code changes from P0025 to P0022, you have confirmed the solenoid is the faulty component.

Technical Service Bulletins (TSBs) & Recalls

• SSM 54366: Updated diagnostic procedures for P0025 and other VCT codes.
• SSM 50067: Identifies sticking VCT solenoids due to debris as a potential cause for P0025.
• TSB 16-0038: Links P0025 with P0019, pointing to VCT solenoid replacement.

Platform-Specific Known Issues

• TSB SSM 50067: Notes that various VCT codes, including P0025, may be caused by small debris causing the VCT solenoid to stick. It recommends attempting to clear the debris by cycling the solenoid with a scan tool before replacement.
• TSB SSM 54366: Mentions that diagnostic tests for a group of VCT codes, including P0025, have been updated in the official workshop manual, indicating this is a well-documented issue.
• TSB 16-0038: Specifically for 2016 models, this TSB advises that if P0019 and P0025 are present together, the Bank 2 exhaust VCT solenoid should be replaced.
• Access Difficulty: The Bank 2 (firewall side) VCT solenoids are significantly harder to access than Bank 1. On the 3.5L EcoBoost, this repair often requires removing the upper intake manifold, increasing labor time and complexity.

Mechanic-Grade Diagnostic Values

• VCT Solenoid Internal Resistance — expected: 5 to 15 Ohms is a general range, with 6.9-7.9 Ohms or 10-12 Ohms being more specific cited values.. Failure: A reading of 0 Ohms (short), OL/infinity (open circuit), or a value significantly outside the expected range.
• VCT Solenoid Connector Voltage (Key On, Engine Off) — expected: Approximately 12V (Battery Voltage) on the power supply pin.. Failure: Significantly lower or no voltage, which points to a problem in the wiring harness, fuse, or PCM power supply.
• FORScan PID: VCT_EXH_ERR2 (Bank 2 Exhaust Cam Error) — expected: Should be at or very close to 0 degrees at hot idle.. Failure: A consistent, non-zero value (either positive or negative) indicates the camshaft is not at its commanded position, confirming a fault.

Scan Tool Commands That Help

• FORScan / Ford IDS: VCT Solenoid On/Off Command (or similar name under Variable Valve Timing Control) — This bidirectional control allows a technician to command the solenoid on and off to test its mechanical reaction. A healthy solenoid should produce an audible click and a change in engine idle. TSB SSM 50067 specifically recommends cycling the solenoid multiple times to potentially dislodge debris before deciding on replacement.

Wiring & Ground Locations

• PCM Engine Harness Ground — On a 2014 Taurus (similar to 2015-2019), a key ground for the PCM engine harness is located on the transmission case, below the brake booster.. A poor or corroded engine harness ground can cause erratic behavior in sensors and actuators controlled by the PCM, including the VCT solenoids. While not a primary cause, it's a critical check if electrical issues are suspected.
• VCT Solenoid Connector (Bank 2) — Under the Bank 2 (firewall side) valve cover, connected to the VCT solenoids. The exhaust solenoid connector is often a different color (e.g., white) than the intake to prevent mix-ups.. This is the direct connection point for testing voltage, ground signal, and resistance of the solenoid. The wiring leading to this connector can be damaged by heat and abrasion, especially given the difficult access on the firewall side.

OEM Part Supersession History

• AT4Z-6M280-C → AT4Z-6M280-C (current) — This is the specific part number for the Bank 2 (right side) exhaust camshaft VCT solenoid on the 3.5L engine.
  Heads up: Ford uses different part numbers for different solenoid positions. AT4Z-6M280-A is for Bank 1 exhaust/Bank 2 intake, AT4Z-6M280-B is for Bank 1 intake, and AT4Z-6M280-C is for Bank 2 exhaust. Using the wrong part, even if it fits, will cause issues.

Model Year Variations Within This Range

• 2015-2019: Within the 2015-2019 model years for the Taurus, there are no significant documented changes to the 3.5L V6 Duratec or EcoBoost engines that would alter the diagnosis or common causes of code P0025. The primary issue related to VCT solenoids and oil quality remains consistent across this range.