P0018 – Crankshaft Position Camshaft Position Correlation Bank 2 Sensor A

P0018 is a fairly common check engine light code that points to a problem with how your engine’s crankshaft and camshaft are lined up. In simple terms, the engine computer sees that the “timing” between these two critical parts is off. Sometimes it’s caused by a stretched timing chain, worn guides, or a faulty camshaft position sensor. Other times it’s just dirty oil affecting the variable valve timing system. If you catch it early, you can often avoid major engine damage and keep your vehicle running smoothly.

What Does P0018 Mean?

P0018 stands for “Crankshaft Position – Camshaft Position Correlation (Bank 2, Sensor A).” Your engine control unit (ECU) constantly compares the position of the crankshaft and the camshaft using sensors. When their relationship is outside a set range, the ECU stores P0018 and usually turns on the check engine light.

“Bank 2” is the cylinder bank that does not contain cylinder #1 (on V6, V8, etc.), and “Sensor A” is typically the intake camshaft on that bank. This code means the ECU believes the mechanical or hydraulic timing between crank and cam is off, or the sensors reading them are not accurate.

Quick Reference

• Code: P0018
• Meaning: Crankshaft/Camshaft correlation error – Bank 2, Sensor A
• Severity: Moderate to severe (possible engine damage if ignored)
• Common causes: Stretched timing chain, bad cam sensor, dirty oil, VVT issues
• Typical symptoms: Rough running, hard starting, reduced power, poor fuel economy

Real-World Example / Field Notes

In the shop, I see P0018 most often on higher-mileage engines with timing chains, especially certain GM, Hyundai/Kia, and some European V6 engines. One common case: a customer complains of rough idle and poor acceleration, with P0018 and sometimes misfire codes. Oil changes were “whenever I remember.” The oil is thick and dirty, the timing chain has noticeable slack, and the cam phaser is slow to respond. After a timing set replacement and a few short-interval oil changes, the engine smooths out and P0018 stays gone.

Symptoms of P0018

• Check engine light on: P0018 usually sets a MIL (check engine) and may store as a pending code first.
• Rough idle: The engine may shake, surge, or feel unstable at stoplights.
• Loss of power: You may notice sluggish acceleration, especially at low RPM.
• Hard starting or no-start: In more severe cases, the engine cranks longer or may not start at all.
• Poor fuel economy: Incorrect valve timing can cause the engine to burn more fuel than normal.
• Engine noise: Rattling from the timing chain area on cold start can point to chain or tensioner problems.
• Stalling: The engine may stall when coming to a stop or when shifting into gear.
• Other codes present: You might see related VVT, cam sensor, or misfire codes along with P0018.

Common Causes of P0018

Most Common Causes

• Stretched timing chain or worn belt: Over time, chains stretch and belts wear, throwing off cam/crank alignment.
• Worn timing chain guides or tensioner: Plastic guides can break and tensioners can weaken, allowing chain slack.
• Faulty camshaft position sensor (Bank 2): A bad sensor can send incorrect position data to the ECU.
• Dirty or low engine oil: Thick, contaminated, or low oil affects variable valve timing (VVT) operation.
• Sticking VVT (cam phaser) on Bank 2: If the cam phaser can’t move or return properly, timing correlation goes out of range.
• Faulty VVT solenoid (oil control valve): A clogged or failed solenoid can prevent proper cam timing adjustment.

Less Common Causes

• Incorrect timing after engine work: A timing chain or belt installed one tooth off will trigger P0018.
• Damaged reluctor wheel or tone ring: The crank or cam trigger wheel can slip, crack, or be installed incorrectly.
• Wiring issues: Corroded connectors, broken wires, or poor grounds at the cam or crank sensor circuits.
• ECU software or internal fault: Rare, but a reflash or replacement may be needed if all mechanical and sensor checks pass.
• Severe engine wear: Excessive chain, sprocket, or camshaft wear on high-mileage engines can cause correlation errors.

Diagnosis: Step-by-Step Guide

Basic tools you’ll want include a quality OBD-II scan tool (preferably with live data and Mode $06), a digital multimeter, basic hand tools, and a service manual or repair database for your specific vehicle. For deeper diagnosis, a scope and mechanical timing tools are helpful but not mandatory for a first pass.

1. Verify the code: Scan the vehicle, confirm P0018 is present, and note any companion codes (P0016–P0022, misfires, oil pressure, etc.). Clear the codes and see if P0018 returns immediately or after a drive.
2. Check oil level and condition: Make sure the oil is at the correct level and not thick, sludged, or burnt. If it’s overdue, change it with the correct viscosity and a quality filter.
3. Visual inspection: Inspect the cam and crank sensor connectors and wiring on Bank 2. Look for oil intrusion, broken clips, chafed wires, or corrosion.
4. Live data review: With a capable scan tool, monitor camshaft advance/retard angles and desired vs. actual cam position for Bank 2. Large differences, especially at idle, indicate a mechanical or VVT issue.
5. Test camshaft and crank sensors: Use a multimeter or scope (if available) to check sensor power, ground, and signal. Compare Bank 1 vs. Bank 2 readings when possible.
6. Check VVT solenoid operation: Command the Bank 2 VVT solenoid on and off with a scan tool if the function is available. Listen/feel for operation and check for debris in the oil control valve screen.
7. Inspect for timing chain/belt noise: Listen on cold start for rattling near the timing cover. Any loud chain slap or rattle is a red flag for stretched chain or failed tensioner.
8. Mechanical timing verification: If the above checks don’t reveal the problem, remove necessary covers and use factory timing marks and locking tools to confirm the cam and crank are mechanically aligned.
9. Mode $06 and freeze frame: Review Mode $06 data and freeze frame to see when P0018 sets (RPM, load, temperature). This can help you identify intermittent vs. constant issues.
10. Re-test after each repair: After any repair or cleaning, clear codes and perform a proper drive cycle to confirm P0018 does not return.

Pro tip: Always rule out oil and basic electrical issues before diving into a full timing chain job. Many P0018 cases are fixed with proper oil service and a new VVT solenoid or cam sensor, especially when caught early.

Possible Fixes & Repair Costs

The exact repair depends on what’s causing P0018, but it usually falls into a few categories. Simple fixes include an oil change with the correct viscosity, replacing a camshaft position sensor, or installing a new VVT solenoid. More involved repairs include replacing a stretched timing chain, worn guides and tensioners, or correcting incorrectly installed timing components after previous engine work. Typical repair costs range from about $150–$350 for sensors or solenoids, $80–$150 for an oil service with cleaning, and $800–$2,000+ for full timing chain or phaser repairs, depending on engine design, labor rates, and how much disassembly is required.

Can I Still Drive With P0018?

You can sometimes drive for a short period with P0018, but it’s not something you should ignore. If the engine is running relatively smooth and you don’t hear loud rattling or knocking, you may be able to drive gently to a shop or home. However, if the engine is misfiring, stalling, or making metallic noises, you should avoid driving and have it towed. Continuing to drive with severe timing issues can lead to bent valves or even complete engine failure.

What Happens If You Ignore P0018?

Ignoring P0018 can turn a manageable repair into a very expensive one. A stretched chain or failing tensioner can eventually jump timing far enough for the pistons and valves to collide on interference engines, bending valves and damaging pistons. Long-term incorrect valve timing also increases fuel consumption, emissions, and carbon buildup. In short, you risk turning a few-hundred-dollar repair into a multi-thousand-dollar engine replacement.

Last updated: March 1, 2026

Vehicles Commonly Affected by P0018

P0018 shows up across many makes, but some platforms see it more often. It’s common on GM V6 and V8 engines (Chevrolet, GMC, Buick, Cadillac), especially those with timing chain stretch issues. Hyundai and Kia 4-cylinder and V6 engines with GDI and VVT systems also frequently log this code. You’ll also see it on certain Toyota/Lexus, BMW, Mercedes-Benz, and Audi/VW engines that rely heavily on variable valve timing and long-life timing chains. High-mileage vehicles with extended oil change intervals are especially prone to P0018.