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P0025 Code Explained: “B” Camshaft Position Timing Over-Retarded Bank 2 Causes, Symptoms & Fixes

OBD-II scanner displaying P0025 beside a Bank 2 exhaust camshaft phaser, VVT solenoid, retarded timing graphic and illuminated Check Engine Light

If your OBD-II scanner displays P0025, your vehicle’s Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected that the Bank 2 “B” camshaft is more retarded than commanded or is failing to advance to its requested position.

On most dual-overhead-cam engines, Camshaft B refers to the exhaust camshaft, while Bank 2 is the side of the engine opposite Bank 1. Bank 1 contains cylinder number one, so Bank 2 is the other cylinder bank.

Modern engines use variable valve timing to advance or retard the exhaust camshaft according to engine speed, load, temperature, throttle position and emissions requirements. When the ECM commands the Bank 2 exhaust camshaft to advance but detects that it remains too far retarded, it stores P0025.

P0025 is commonly caused by:

P0025 should be diagnosed promptly. Some vehicles may continue running with only a Check Engine Light, but excessively retarded exhaust camshaft timing can cause poor acceleration, rough idle, hard starting, increased emissions, misfires and possible internal engine damage.

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P0025 Quick Facts

ItemInformation
OBD-II codeP0025
Official description“B” Camshaft Position Timing Over-Retarded Bank 2
CategoryPowertrain
SystemVariable valve timing
Code typeGeneric SAE powertrain code
SeverityModerate to high
Safe to drive?Limited driving only; diagnose promptly
Most common causesDirty oil, sticking VVT solenoid, failed phaser, timing-chain wear
Typical repair cost$60–$4,000+

What Does the P0025 Code Mean?

P0025 means “‘B’ Camshaft Position Timing Over-Retarded Bank 2.”

The ECM commanded the Bank 2 exhaust camshaft to a specific position but detected that the camshaft:

The ECM determines camshaft position by comparing signals from the:

The ECM also monitors the duty-cycle command sent to the Bank 2 exhaust VVT solenoid.

If the actual exhaust camshaft angle remains behind the requested angle, the ECM may store P0025.

P0025 is closely related to:

What Does Camshaft B Mean?

On most dual-overhead-cam engines:

The exhaust camshaft controls when the exhaust valves open and close.

The ECM adjusts exhaust camshaft timing to improve:

If the exhaust camshaft remains excessively retarded, the exhaust valves may open and close later than intended.

This can affect:

Manufacturer terminology may vary, so confirm Camshaft B using vehicle-specific service information.

What Is Bank 2?

Bank 2 is the side of the engine that does not contain cylinder number one.

Bank 2 exists on engines with more than one cylinder bank, including:

Inline engines normally have only Bank 1 and should not store a true Bank 2 code.

Bank 2 may be located on either side of the vehicle depending on the engine design.

Confirm Bank 2 using:

Do not assume Bank 2 is always the driver side or passenger side.

What Does Over-Retarded Exhaust Camshaft Timing Mean?

Camshaft timing is considered retarded when the camshaft rotates behind its normal or commanded position relative to the crankshaft.

The ECM intentionally advances and retards the exhaust camshaft during normal operation.

P0025 does not mean that all camshaft retard is abnormal. It means the Bank 2 exhaust camshaft is:

The cause may be:

How Exhaust Variable Valve Timing Works

A typical exhaust variable valve timing system includes:

The system operates as follows:

  1. The ECM calculates the desired exhaust camshaft angle.
  2. The ECM sends a duty-cycle command to the Bank 2 exhaust VVT solenoid.
  3. The solenoid routes pressurized oil into the camshaft phaser.
  4. The phaser rotates the exhaust camshaft relative to the timing sprocket.
  5. The exhaust camshaft position sensor reports the actual angle.
  6. The ECM adjusts the solenoid command to maintain the requested position.

If oil cannot reach the advance side of the phaser, or if the phaser cannot move, the exhaust camshaft may remain over-retarded.

This may happen because of:

How the ECM Detects P0025

The ECM compares:

P0025 may be stored when:

Some vehicles may set P0025 during:

Symptoms of the P0025 Code

Symptoms vary depending on how far the Bank 2 exhaust camshaft is retarded and whether the fault is intermittent.

Common symptoms include:

Some vehicles may show no noticeable symptoms beyond the warning light.

If the exhaust camshaft remains severely retarded, the engine may run poorly or fail to start.

Common Causes of P0025

1. Dirty Engine Oil

Dirty oil is one of the most common causes of variable valve timing problems.

Contaminated oil may create:

The VVT system relies on precise oil flow through small passages.

Even moderate contamination may prevent the Bank 2 exhaust camshaft from advancing properly.

2. Incorrect Oil Viscosity

Oil that is too thick or too thin can interfere with camshaft-phaser operation.

Oil that is too thick may:

Oil that is too thin may:

Always use the manufacturer-specified oil viscosity and oil standard.

3. Low Engine-Oil Level

Low engine oil can reduce the hydraulic pressure available to the VVT system.

Low oil may be caused by:

The system may not have enough oil pressure to advance the Bank 2 exhaust camshaft.

4. Low Engine-Oil Pressure

The oil level may be correct while actual oil pressure remains too low.

Possible causes include:

Low oil pressure may affect:

A mechanical oil-pressure test may be required.

5. Sticking Bank 2 Exhaust VVT Solenoid

The Bank 2 exhaust VVT solenoid regulates oil flow to the camshaft phaser.

If the solenoid sticks in the retarded or default position, the camshaft may fail to advance.

Possible causes include:

A solenoid may pass a resistance test while still sticking mechanically.

6. Clogged VVT Solenoid Screen

Some VVT solenoids contain a small filter screen.

The screen may become clogged with:

A restricted screen can reduce oil flow to the camshaft phaser’s advance chamber.

7. Restricted VVT Oil Passages

Oil passages supplying the exhaust camshaft phaser may become restricted.

Possible causes include:

A restricted supply passage may prevent adequate oil pressure from reaching the phaser.

8. Failed Bank 2 Exhaust Camshaft Phaser

The exhaust camshaft phaser may fail mechanically or hydraulically.

A failed phaser may:

A worn phaser may require more oil pressure than the engine can provide.

9. Stretched Timing Chain

A stretched timing chain may cause the exhaust camshaft to lag behind the crankshaft.

This makes timing-chain wear a common mechanical cause of over-retarded camshaft codes.

Common signs include:

P0019 or P0009 may appear with P0025 when chain wear becomes severe.

10. Failed Timing-Chain Tensioner

A failed chain tensioner may allow excessive chain slack.

Possible failures include:

Chain slack may allow the exhaust camshaft to remain retarded relative to the crankshaft.

A tensioner that drains down overnight may cause a startup rattle.

11. Worn or Broken Timing Guides

Timing-chain guides keep the chain aligned and properly tensioned.

They may:

Broken guide material may fall into the oil pan and restrict the oil pickup, creating both timing and oil-pressure problems.

12. Jumped Timing Chain or Belt

A timing chain or timing belt may jump one or more teeth.

Possible causes include:

A jumped timing system may cause:

13. Incorrect Mechanical Timing

P0025 may appear after:

Possible mistakes include:

If P0025 appears immediately after engine work, verify mechanical timing before replacing additional parts.

14. Faulty Exhaust Camshaft Position Sensor

The Bank 2 exhaust camshaft position sensor may provide inaccurate or intermittent data.

Possible sensor problems include:

However, the sensor may be correctly reporting a real timing problem.

Do not replace it based only on P0025.

15. Shifted Camshaft Reluctor Wheel

The exhaust camshaft position sensor reads a reluctor or trigger wheel mounted on the camshaft or phaser.

The reluctor may become:

A shifted reluctor may make the exhaust camshaft appear retarded even when mechanical timing is correct.

16. Damaged Wiring or Connectors

Wiring faults may prevent the ECM from controlling the exhaust VVT solenoid correctly.

Inspect for:

An electrical actuator fault may also store P0023.

17. Faulty ECM or PCM

ECM failure is uncommon but possible.

A damaged ECM driver or software problem may:

Before replacing the ECM, verify:

18. Incorrect Replacement Components

An incorrect replacement component may cause P0025.

Examples include:

A component may physically fit while having different hydraulic or timing characteristics.

Is P0025 an Electrical or Mechanical Code?

P0025 is primarily a camshaft timing-performance code.

It does not directly identify one failed electrical circuit.

The underlying cause may be:

P0025 differs from P0023, which primarily indicates an electrical fault in the Bank 2 exhaust camshaft actuator circuit.

P0025 means the exhaust camshaft’s actual position is more retarded than the ECM expects.

How Serious Is the P0025 Code?

P0025 ranges from moderately serious to severe.

The seriousness depends on the underlying cause.

A dirty or sticking VVT solenoid may cause poor performance without immediate internal engine damage.

A stretched or jumped timing chain can lead to catastrophic failure.

Ignoring P0025 may result in:

The code is especially serious when accompanied by:

Can You Drive With P0025?

Limited driving may be possible if:

Continued driving is not recommended until the cause is identified.

Stop driving immediately if you notice:

A mechanical timing problem may cause major engine damage with little additional warning.

How to Diagnose P0025

Step 1: Scan for Additional Codes

Use an OBD-II scanner to check for related trouble codes.

Common companion codes include:

Record:

Do not clear the codes before recording this information.

Step 2: Confirm Bank 2 and Camshaft B

Use vehicle-specific service information to identify:

Incorrect bank or camshaft identification can lead to testing or replacing the wrong parts.

Step 3: Check the Engine-Oil Level

Check the oil with the vehicle positioned according to manufacturer instructions.

Look for:

Correct the oil level before continuing.

An overfilled engine may aerate the oil and cause unstable VVT operation.

Step 4: Inspect Oil Condition and Viscosity

Determine whether the oil is:

Perform an oil and filter change if needed.

Use the exact manufacturer-specified viscosity and oil standard.

Step 5: Review Maintenance and Repair History

Determine:

P0025 appearing immediately after repair often suggests incorrect mechanical timing or an installation problem.

Step 6: Inspect Wiring and Connectors

Inspect the Bank 2 exhaust VVT solenoid and exhaust camshaft-position sensor circuits.

Look for:

Repair electrical faults before condemning hydraulic or mechanical components.

Step 7: Test the Bank 2 Exhaust VVT Solenoid Electrically

Test the solenoid for:

Compare all readings with manufacturer specifications.

A circuit fault may store P0023 together with P0025.

Step 8: Command the VVT Solenoid With a Scan Tool

Use a bidirectional scan tool when available.

Command the Bank 2 exhaust camshaft through its operating range.

Monitor:

Possible results include:

Step 9: Remove and Inspect the VVT Solenoid

Remove the Bank 2 exhaust VVT solenoid according to the service procedure.

Inspect for:

Clean or replace the solenoid as appropriate.

Do not use aggressive chemicals that may damage internal seals or coatings.

Step 10: Compare Bank 1 and Bank 2 Solenoids

If the exhaust VVT solenoids are identical, compare:

Some technicians temporarily swap identical solenoids between banks.

Only do this when:

If the fault moves to Bank 1, the solenoid is likely defective.

Step 11: Monitor Camshaft Position Data

Compare:

If Bank 1 responds normally while Bank 2 remains retarded, suspect a Bank 2-specific fault.

Possible causes include:

Step 12: Check Engine-Oil Pressure

Install a mechanical oil-pressure gauge if low pressure is suspected.

Measure pressure at:

Compare the readings with factory specifications.

Do not assume oil pressure is normal because the dashboard warning light remains off.

Step 13: Test the Exhaust Camshaft Position Sensor

Inspect and test the Bank 2 exhaust camshaft position sensor.

Depending on sensor type, test:

Use an oscilloscope when possible.

A distorted signal may make a correctly positioned camshaft appear over-retarded.

Step 14: Compare Camshaft and Crankshaft Waveforms

Use an oscilloscope to compare:

Compare the waveform with known-good data.

This may reveal:

Step 15: Inspect the Exhaust Camshaft Phaser

If the solenoid, wiring and oil pressure are correct, inspect the exhaust camshaft phaser.

Possible signs of phaser failure include:

Phaser replacement may require substantial engine disassembly.

Step 16: Verify Mechanical Timing

If scan data or waveform testing suggests a mechanical timing fault, verify timing alignment.

This may require removing:

Position the engine at top dead center and inspect:

Use the required locking tools and manufacturer procedures.

Step 17: Inspect the Reluctor Wheel

If mechanical timing is correct but the code remains, inspect the exhaust camshaft reluctor wheel.

Look for:

A shifted reluctor may require replacement of the camshaft or phaser.

Step 18: Check Technical Service Bulletins

Some vehicles have known P0025-related issues involving:

Review manufacturer service information before beginning major repairs.

Step 19: Verify the Repair

After completing repairs:

  1. Clear all stored codes.
  2. Start the engine from cold.
  3. Listen for timing-system noise.
  4. Monitor commanded and actual exhaust camshaft position.
  5. Command the VVT system with a scan tool.
  6. Check for oil leaks.
  7. Complete the manufacturer’s drive cycle.
  8. Rescan for pending codes.

A successful repair should restore proper Bank 2 exhaust camshaft control and prevent P0025 from returning.

Common P0025 Repairs and Costs

RepairEstimated cost
Diagnostic inspection$100–$300
Engine oil and filter change$60–$180
Clean VVT solenoid or screen$100–$250
Repair VVT wiring$100–$600
Replace Bank 2 exhaust VVT solenoid$150–$500
Replace exhaust camshaft position sensor$150–$450
Clean restricted oil passages$200–$800
Replace Bank 2 exhaust camshaft phaser$600–$1,800
Replace timing-belt kit$700–$2,000
Replace timing chain, guides and tensioners$1,200–$4,000
Repair cylinder-head damage$2,500–$6,000+
Replace engine$4,000–$12,000+
ECM software update$100–$300
Replace and program ECM$1,000–$2,500+

Repair costs vary according to:

Common Diagnostic Mistakes

Replacing the Camshaft Position Sensor First

P0025 does not automatically mean the exhaust camshaft position sensor has failed.

The sensor may be accurately reporting that the camshaft is over-retarded.

Confusing P0025 With P0023

P0023 is an actuator electrical-circuit code.

P0025 means the actual Bank 2 exhaust camshaft timing is more retarded than expected.

Confusing P0025 With P0024

P0024 indicates over-advanced timing.

P0025 indicates over-retarded timing.

Replacing the VVT Solenoid Without Checking the Oil

Dirty, low or incorrect oil can cause the same symptoms as a failed solenoid.

Always inspect the oil first.

Assuming an Oil Change Will Repair Mechanical Wear

Fresh oil may help a sticking solenoid.

It cannot repair:

Confusing Bank 1 and Bank 2

Bank 1 contains cylinder number one.

Bank 2 is the opposite bank.

Testing the wrong bank may lead to unnecessary parts replacement.

Confusing Camshaft A and Camshaft B

Camshaft A usually refers to the intake camshaft.

Camshaft B usually refers to the exhaust camshaft.

Confirm the designation before repairs.

Ignoring Startup Rattle

Startup rattling may indicate:

Ignoring the noise may lead to major engine damage.

Skipping Oil-Pressure Testing

A correct oil level does not guarantee adequate oil pressure.

Low pressure can prevent the exhaust camshaft phaser from advancing.

Failing to Compare Both Banks

Comparing Bank 1 and Bank 2 exhaust camshaft operation can show whether the fault is localized or system-wide.

Replacing the ECM Too Early

ECM failure is uncommon compared with:

Verify the complete system before replacing the module.

Vehicles Commonly Affected by P0025

P0025 may appear on OBD-II vehicles equipped with multiple cylinder banks and exhaust variable valve timing.

Potentially affected manufacturers include:

P0025 is commonly associated with engines using:

The code alone does not prove that a particular vehicle has a known defect.

Diagnosis must be based on the exact:

How to Prevent P0025

Helpful preventive measures include:

Good oil maintenance is one of the best ways to prevent exhaust camshaft timing and VVT problems.

Frequently Asked Questions About P0025

What does code P0025 mean?

P0025 means the Bank 2 exhaust camshaft is more retarded than commanded or is failing to advance to its requested position.

Is Camshaft B the exhaust camshaft?

On most engines, yes.

Camshaft B usually refers to the exhaust camshaft.

Which side is Bank 2?

Bank 2 is the side of the engine that does not contain cylinder number one.

Its physical location varies by engine.

Is P0025 an electrical code?

Not primarily.

P0025 is a camshaft timing-performance code. The underlying cause may still be electrical, hydraulic or mechanical.

What is the difference between P0023 and P0025?

P0023 identifies an electrical fault in the Bank 2 exhaust camshaft actuator circuit.

P0025 means the Bank 2 exhaust camshaft is too retarded or is failing to advance properly.

What is the difference between P0024 and P0025?

P0024 indicates over-advanced exhaust camshaft timing.

P0025 indicates over-retarded exhaust camshaft timing.

Can dirty oil cause P0025?

Yes. Dirty oil can clog the VVT solenoid, camshaft phaser or oil passages.

Can low oil cause P0025?

Yes. Low oil may prevent sufficient hydraulic pressure from reaching the exhaust camshaft phaser.

Can the wrong oil viscosity cause P0025?

Yes. Incorrect oil viscosity can slow phaser response and prevent the camshaft from advancing properly.

Can a bad VVT solenoid cause P0025?

Yes. A sticking Bank 2 exhaust VVT solenoid is a common cause.

Can a bad camshaft phaser cause P0025?

Yes. A failed exhaust camshaft phaser may remain stuck in a retarded position or fail to advance.

Can a stretched timing chain cause P0025?

Yes. Timing-chain wear often causes the camshaft to lag behind the crankshaft.

Can a bad camshaft sensor cause P0025?

Yes, but it is less common than oil, VVT solenoid, phaser or mechanical timing problems.

Test the sensor before replacement.

Can P0025 cause rough idle?

Yes. Incorrect exhaust camshaft timing can cause rough idle, misfires and unstable combustion.

Can P0025 cause poor acceleration?

Yes. A retarded exhaust camshaft may reduce engine breathing, torque and high-RPM performance.

Can P0025 affect turbocharger performance?

Yes. On some turbocharged engines, incorrect exhaust valve timing may reduce turbine energy and slow turbocharger response.

Can P0025 cause hard starting?

Yes. Incorrect valve timing may cause extended cranking or hard starting.

Can P0025 cause a no-start condition?

Yes, especially if the timing chain or timing belt has jumped significantly.

Can I drive with P0025?

Limited driving may be possible if the engine runs normally and makes no unusual noise.

Prompt diagnosis is recommended because the code may indicate a serious timing-system problem.

Will an oil change fix P0025?

It may help if dirty or incorrect oil is causing a sticking VVT solenoid.

It will not repair a failed phaser, stretched chain, jumped timing belt or incorrect mechanical timing.

How much does it cost to fix P0025?

An oil service may cost under $200.

A VVT solenoid replacement commonly costs $150 to $500.

Camshaft-phaser or timing-chain repairs may cost $600 to $4,000 or more.

Will clearing P0025 fix the vehicle?

No. Clearing the code only removes the warning temporarily.

The code will return if the exhaust camshaft timing problem remains.

Will P0025 fail an emissions test?

Yes. An active Check Engine Light or emissions-related powertrain code will generally cause an OBD-based emissions inspection failure.

Final Thoughts

The P0025 code means the Bank 2 exhaust camshaft is over-retarded or is failing to follow the ECM’s commanded position.

The most common causes include:

Begin diagnosis by checking the engine-oil level, condition and viscosity. Confirm Bank 2 and Camshaft B before inspecting the exhaust VVT solenoid and related wiring.

Use a capable scan tool to compare commanded and actual exhaust camshaft position. If the camshaft remains retarded, inspect the solenoid, oil passages, oil pressure, exhaust camshaft phaser and mechanical timing.

Do not assume P0025 is simply caused by a bad sensor. The code may indicate timing-chain wear or another mechanical problem capable of causing severe engine damage.

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