P0018 No noticeable engine trouble


Year: 2018

Miles: 74500

Indication: Check Engine Light

Remarks: The car starts and accelerates fine. There are no noticeable operational defects other than the check engine light.

Repairs Made:

  • Replaced Camshaft Sensor
  • Changed Oil

Result: Problem persists

Raw code: 0018
ECU: Engine control unit
Status: Confirmed
OBDII: Crankshaft position/camshaft position, bank 2 sensor A - correlation

That code usually indicates the timing chain is stretched.



… which is a probable indication of poor maintenance over the years, but the OP failed to mention the model year and the odometer mileage, so that is just a guess.

If the OP bought this as a used car, it is a likely indication that the previous owner(s) went far too long between oil changes and/or they used oil of the wrong viscosity. In either event, much more serious engine problems could be on the way if the timing chain is indeed stretched.


I was hoping it’s a wiring issue because no other symptoms accompany the code. What does a repair like that usually cost?

Thank you for your help. The car was purchased used. What does a repair like this usually cost?

Fuel economy and performance can degrade a bit if the timing chain stretches and the valve timing changes. Does the vehicle burn an excessive amount of oil?

That was a random web search. It could be legit, or it could be spam like automatically generated content, or somebody in India who knows nothing about cars copying and pasting things to make web pages for search engine and advertising hits.

Every vehicle that came into the shop with that code got a new timing chain.


Search here…

Does your engine use the variable valve timing function?

Thought most Subaru’s had timing belts ?

Then if that’s true, the timing belt may have jumped a tooth.


So what year model is it?

They did, up until a few years ago. However, the OP has still not revealed the model year or the odometer mileage of his Impreza.

Year: 2018
Miles 74500

Then, it has a timing chain, and not a timing belt, so I strongly suggest that you think about the advice provided by Tester. If you are going to get the timing chain replaced, make sure you ask the mechanic to first check for build-up of damaging oil sludge. If the engine is heavily caked with internal oil sludge, there can be significant additional engine issues in the future.

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Thank you for your help. Is there anything I can do if the engine is heavily caked with internal oil sludge, to try and prevent more issues down the road?

Talk to a mechanic–a REAL mechanic, and not someone at Pep Boys, Midas, Meineke, Monro, AAMCO, or a tire store–about the possibility of cleaning the sludge out of the engine.

Edited to add:
And, don’t take advice from anyone at Quicky Lube. Those guys are NOT mechanics, and many of them can’t even perform an oil change without screwing-up.


A timing chain failure (IF true) at only 74k miles would give me pause. Chain failures are generally caused by irregular oil changes and/or insufficient oil levels. This means the rest of the engine is also going through premature wear.

What would I do if in your shoes? Run a compression test and an oil pressure check. I would want 180 or so PSI on the compression and around 40 PSI on the oil pressure at idle. The oil pressure can vary depending upon age of the oil, weight of the oil, and so on.
I would just want to know what I’m dealing with as that information could affect any decision on whether or not to keep the car.

An easy and preliminary test before checking compression is to have a vacuum test done. This is quick, easy, and can reveal whether or not to proceed with the compression test. Manifold vacuum at idle should be 20-21 inches of mercury at idle and the gauge needle should be rock steady with NO quivering or vibrating.

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I’m seeing the 2.0 L DOHC engine used in a 2018 Sub Imp uses variable valve timing functionality. If that’s correct in OP’s case, suggest to also consider the possibility of a problem with the timing actuator(s).