P0025 on 2015-2021 Ford Mustang V6/V8: Exhaust Cam Timing Over-Retarded Causes & Fixes

What's Unique About the 2015-2021 Ford MUSTANG

On the popular 5.0L Coyote V8 engine in this Mustang generation, the four VCT solenoids are located underneath the valve covers. This makes replacing them a more involved and costly job than on many other engines. For 2018+ models with the Gen 3 Coyote V8, the addition of a high-pressure fuel pump (HPFP) driven by the passenger side exhaust cam further complicates access to the passenger side valve cover. Ford has also issued technical service bulletins (TSBs) acknowledging that debris in the engine oil can cause these solenoids to stick, indicating a high sensitivity to oil quality 🎬 Watch: Ford's explanation of VCT solenoid codes and oil debris issues. and maintenance intervals.

Diagnostic Flowchart

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

Generation note: This range covers the S550 Mustang generation. However, there are key differences: the 3.7L V6 engine was only offered from 2015-2017. The 5.0L V8 was updated in 2018 (Gen 3), and the VCT solenoids used in 2018 and newer models have different part numbers than the 2015-2017 models. Always verify the part number with your vehicle's VIN.

Symptoms You May Notice

• Illuminated Check Engine Light
• Rough, unstable, or low idle
• Engine stalling when coming to a stop or at idle
• Reduced engine power and sluggish acceleration
• Hesitation when accelerating
• Engine ticking, chattering, or knocking sounds, sometimes at specific RPMs
• Decreased fuel economy
🎬 See a breakdown of common symptoms when VVT solenoids fail.

Most Likely Causes

1. Low or Dirty Engine Oil 🔴 High Probability The VCT system is hydraulic and highly sensitive to oil pressure and cleanliness. Ford TSBs confirm that small debris in the oil can cause the VCT solenoids to stick or their internal screens to become clogged.
   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 past its service interval, it needs to be changed.
   Typical fix: Perform an engine oil and filter change using the manufacturer-specified grade (typically 5W-20 or 5W-30 for the 5.0L V8, check owner's manual) and a high-quality filter.
   Est. part cost: $50-$100
2. Faulty Bank 2 Exhaust VCT Solenoid 🔴 High Probability The solenoid can become clogged with debris, its internal screen can tear, or it can fail electrically, causing it to stick. This is a well-documented issue on Ford's Coyote engines, leading to multiple TSBs.
   How to confirm: A mechanic can use a scan tool to command the solenoid on and off (a 'cycle test' per Ford's Pinpoint Test HK) to see if it responds and potentially clears debris. A common DIY method is to swap the Bank 2 exhaust solenoid with the Bank 2 intake solenoid. If the code changes from P0025 to P0021 (Intake Cam Position Timing Over-Advanced), the solenoid is confirmed bad.
   Typical fix: Replace the Bank 2 (driver's side) exhaust VCT solenoid. This requires removing the driver's side valve cover.
   Est. part cost: $40-$120
3. Failed Cam Phaser ⚪ Low Probability The phaser is the mechanical gear that the solenoid controls. It can fail internally from wear or oil contamination, getting stuck in one position. This is less common than a solenoid failure but is a known issue on higher mileage Coyote engines.
   How to confirm: This is difficult to confirm without advanced diagnostics. A mechanic would use a scan tool to monitor desired vs. actual cam angle data while the engine is running. A large, erratic discrepancy that doesn't resolve with a new solenoid points to the phaser.
   Typical fix: Replace the Bank 2 exhaust cam phaser. This is a major repair that involves removing the timing cover.
   Est. part cost: $150-$300

Rare But Worth Checking

• Stretched Timing Chain or Failed Tensioner: While not the most common cause for an isolated P0025, significant timing chain wear can cause the base timing to be off, contributing to VCT-related codes. This is usually accompanied by rattling noises, especially on startup.
• Blown VCT Solenoid Fuse: A blown fuse can cut power to the VCT solenoids, preventing them from operating. On a 2018 Mustang, for example, the fuse for the VCT solenoids is fuse #44 in the under-hood fuse box. Always check for simple electrical issues before replacing components.

Diagnosis Steps

1. Check Engine Oil: Verify the oil level is correct and the oil is clean. If low, top it off. If dirty or past its change interval, perform an oil and filter change with the correct viscosity oil. This is the cheapest and easiest first step.
2. Scan for Codes: Use an OBD-II scanner to confirm P0025 and check for any other related codes, such as P0019 or misfire codes.
3. Inspect Solenoid Wiring and Fuse: Visually inspect the electrical connector on the Bank 2 (driver's side) valve cover for the exhaust VCT solenoid. Ensure it's secure and free of corrosion or damage. Check the VCT solenoid fuse (e.g., fuse #44 in the engine bay fuse box on 2018+ models).
4. Test the Solenoid: If you have a capable scan tool, perform the VCT solenoid 'cycle test' as described in Ford's TSB SSM 50067. This may clear debris. A reliable DIY alternative is to swap the exhaust and intake solenoids on Bank 2. They are identical parts. Clear the codes and drive the car. If the code changes to P0021, the solenoid you moved is faulty.
5. Replace the Solenoid: If the solenoid is determined to be faulty, replace it. This will require removing the driver's side valve cover and the valve cover gasket.
6. Seek Professional Diagnosis: If a new solenoid and clean oil do not resolve the code, the issue is likely more severe (cam phaser, timing chain, oil pressure issue). This requires professional diagnosis with specialized tools.

Parts You'll Likely Need

• Variable Camshaft Timing (VCT) Solenoid (OEM #BR3Z-6M280-D (2015-2017 5.0L), HL3Z-6M280-A (2018-2021 5.0L)) — This is the most common point of failure, often getting stuck or clogged with oil debris. Part numbers differ between Gen 2 (pre-2018) and Gen 3 (2018+) Coyote engines.
  Trusted brands: Motorcraft, Dorman
  OEM price range: $70-$120
  Aftermarket price range: $40-$80
• Valve Cover Gasket (OEM #FR3Z-6584-A (Driver Side, 2015-2017), JR3Z-6584-A (Driver Side, 2018-2021)) — Required for replacing the VCT solenoid on the 5.0L V8, as the solenoid is located under the valve cover. It's best practice to replace the gasket anytime the cover is removed.
  Trusted brands: Motorcraft, Fel-Pro
  OEM price range: $40-$60
  Aftermarket price range: $25-$40
• Engine Oil & Filter (OEM #XO-5W20-Q1SP (Motorcraft 5W-20), FL-500S (Filter)) — Low or contaminated oil is a primary cause of this code. An oil change is the first diagnostic step and essential for the health of the VCT system.
  Trusted brands: Motorcraft
  OEM price range: $60-$100
  Aftermarket price range: $50-$80

Related Codes That Often Appear With This One

• P0019 — This code ('Crankshaft Position - Camshaft Position Correlation Bank 2 Sensor B') often appears with P0025 because it indicates a mismatch between where the crank and the Bank 2 exhaust cam are, which is the direct result of an over-retarded cam.
• P0300, P0307, P0308 — Misfire codes (P0300 for random, P0307/P0308 for cylinders on Bank 2) can occur because the incorrect exhaust valve timing disrupts the combustion process in the affected cylinders.

Technical Service Bulletins (TSBs) & Recalls

• SSM 50067: Affects 2015-2021 Ford/Lincoln vehicles. States that codes like P0025 may be due to small debris causing the VCT solenoid to stick. It advises against immediate component replacement, instead directing technicians to first use a scan tool to cycle

Platform-Specific Known Issues

• On the 5.0L Coyote V8, the VCT solenoids are located under the valve covers, which significantly increases the labor time and cost for replacement compared to engines with external solenoids.
• Ford has issued multiple Special Service Messages (SSMs) indicating that these engines are prone to VCT issues caused by small debris in the oil, highlighting the importance of regular, high-quality oil changes.
• A user on Mustang6G.com with a 2018 GT experienced multiple misfire codes along with P0025. The dealer diagnosed and replaced the exhaust cam solenoid under warranty, which resolved the issue.

Mechanic-Grade Diagnostic Values

• VCT Solenoid Resistance — expected: 5-15 Ohms. Failure: A reading outside this range, or an open circuit (infinite resistance), indicates a failed solenoid coil.
• Ford-specific PID: VCT_EXH_ERR2 — expected: Close to 0 degrees at idle.. Failure: A large, persistent non-zero value indicates a significant error between the commanded and actual position of the Bank 2 exhaust camshaft. This points directly to a mechanical or hydraulic issue (solenoid, phaser, oil flow).
• Ford-specific PID: VCT_EXH_DSD2 — expected: Value in degrees that changes with RPM and load.. Failure: If this value changes but the actual cam position (monitored via another PID like VCT_EXH_ACT2) does not follow, it suggests the solenoid is receiving the command but is unable to execute it.

Scan Tool Commands That Help

• Ford IDS (Integrated Diagnostic System): VCT Solenoid On/Off State Control or Cycle Test — This is the bidirectional command referenced in TSB SSM 50067. It allows a technician to manually command the VCT solenoid on and off to check for response and potentially dislodge small debris causing it to stick. This can confirm if the solenoid is electrically responsive.

Wiring & Ground Locations

• Fuse F44 (2018+) — In the under-hood fuse box (Battery Junction Box).. On 2018 and newer Mustangs, this 20A fuse supplies power to all four VCT solenoids. If this fuse is blown, none of the solenoids will operate, potentially causing multiple timing codes including P0025.
• Engine-to-Chassis Ground Strap — On the driver's side, there is a ground strap that provides a path from the engine to the frame. Another important ground runs from the back of the intake manifold to the driver's side firewall.. A poor engine ground can cause erratic behavior in various electronic components, including sensors and solenoids controlled by the PCM. While not a direct cause of P0025, verifying this critical ground is clean and tight is a crucial step in diagnosing any electronic engine issue.
• VCT Solenoid Connector (C1654 - Bank 2 Exhaust) — On the driver's side valve cover, connecting to the exhaust VCT solenoid.. This is the direct electrical connection for the faulty component. Technicians would test for +12V and a pulsing ground signal from the PCM at this connector's pins to verify the wiring and PCM driver are functioning before condemning the solenoid itself.

Real Owner Repair Stories

• Reddit user on r/f150 (same 5.0L engine) (2016 F-150 5.0L) — Not specified, but was replacing VCT solenoids.
  ✅ What actually fixed it The user successfully replaced the VCT solenoids as a DIY job. A key tip mentioned was to be extremely careful that the small rubber grommet on the solenoid does not fall into the timing cover during installation.

OEM Part Supersession History

• BR3Z-6M280-D → BR3Z-6M280-E — Part revision and update by Ford.
  Heads up: A forum user noted that the -E revision has more substantial construction and different spot welds compared to the original part, suggesting a durability improvement.

Model Year Variations Within This Range

• 2018-2021: The Gen 3 Coyote engine introduced in 2018 features both port and direct fuel injection. This adds a high-pressure fuel pump on the passenger-side cylinder head. The engine bore was increased, compression was raised to 12.0:1, and it uses different camshafts and larger valves. These changes mean the VCT solenoids (Part #HL3Z-6M280-A) and valve cover gaskets are different from the 2015-2017 models.
• 2015-2017: The Gen 2 Coyote engine uses only port fuel injection, has an 11.0:1 compression ratio, and uses VCT solenoid Part #BR3Z-6M280-D (or its revision, -E). Access to components is slightly simpler due to the absence of the high-pressure fuel pump and associated hardware found on the Gen 3.