P0017 to P0019: crank-cam correlation on bank 2 and what it costs to ignore

P0016 gets all the attention because it is bank 1 sensor A. P0017, P0018 and P0019 are the same fault on the other camshaft or the other bank, and they carry exactly the same weight.

The full explanation of the mechanism lives in P0016 crankshaft-camshaft correlation. This article is about what the bank 2 variants tell you that P0016 alone does not.

What the numbers map to

Code	Position
P0016	Bank 1, sensor A (usually intake)
P0017	Bank 1, sensor B (usually exhaust)
P0018	Bank 2, sensor A
P0019	Bank 2, sensor B

The pattern in which they appear is diagnostic information in itself.

One bank only points at that bank’s phaser, solenoid or chain — a V-engine often has separate chains or a secondary chain per head.

Both banks together points at something common: the primary chain, the tensioner, or crankshaft timing itself. That is the more serious version.

Read this as a timing fault first

The ECU is comparing two sensor signals and reporting that the relationship between them is outside tolerance. There are only a few ways that happens:

Chain stretch or a failed tensioner

The most common cause on a higher-mileage engine, and the one with real consequences. A chain that has stretched enough to throw the correlation out is a chain that can jump a tooth. On an interference engine, a jumped tooth means valves meeting pistons.

The cold-start rattle is the warning. One or two seconds of noise before oil pressure fills the tensioner is not a quirk of the design.

Timing chain vs belt DTC codes.

Phaser or solenoid on the affected bank

A phaser stuck away from its default position sets correlation codes without any chain wear at all. Check commanded versus actual camshaft position on the affected bank before condemning anything mechanical.

Sensor or reluctor

Least likely, but cheap to eliminate. A damaged reluctor ring or a sensor reading intermittently can produce the same complaint.

Recent timing work

If these codes appeared after a chain or belt job, the assembly is out by a tooth. That is not a diagnostic mystery, it is a rework.

The urgency question

This is the part worth stating plainly.

A correlation code on an interference engine is not something to monitor for a few weeks. If the cause is chain stretch, the failure mode is catastrophic and gives no additional warning.

The practical test: does the engine rattle on cold start? If yes, treat it as a stop-driving fault and have the chain assessed. If no, and the code is intermittent, you have more room — but not indefinitely.

Engine knocking noise diagnosis covers how to distinguish chain noise from the other things that rattle.

Symptoms alongside the code

• Rattle on cold start, fading as oil pressure builds.
• Rough running or a misfire on the affected bank.
• Reduced power, sometimes limp mode.
• Harder starting, particularly hot.

Misfire codes on one bank plus a correlation code for that same bank is a coherent picture, not two problems.

What to record before booking work

1. Freeze frame for the correlation code — engine temperature and RPM at the moment it set.
2. Commanded versus actual camshaft position, both banks, at warm idle.
3. Whether it sets cold, hot or both. Cold-only points at the tensioner.
4. Misfire counters by cylinder.

That set of data is what turns “the light is on” into a specific conversation with a workshop: how to read a workshop quote.

If you are buying the car

A correlation code on a pre-purchase scan is a walk-away or a heavy renegotiation, depending on the engine. It is the single most expensive category of code that a cheap scan can find.

Check whether monitors were recently cleared, because a seller who cleared codes hid exactly this: pending vs stored codes.

Pair an ELM327 adapter, open the free tier of the app and cold-start the engine yourself while logging. On any chain-driven engine, those first seconds carry more information than the rest of the drive.