AT OIL TEMP flashing after a pressure test

Subaru Impreza 2018
74,000 miles

The AT OIL TEMP light is flashing. This light only appeared after a pressure test was performed. The light flashes even when the engine is cold.

Thank you in advance for your help.

Update 1: Transmission fluid level is good.

The only advice I can give you is take it back to the shop that did the test. Mechanic might have left a sensor disconnected.

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Just did that. We also checked the transmission fluid level, it’s good.

Thank you for offering assistance.

Since this is likely a CVT transmission I might ask whether the fluid has ever been changed. The level being good means nothing. Fluid additives break down and IMO a CVT should have the fluid changed every 30k miles or so.

You say the light only appeared AFTER a pressure test was performed so I might ask the reason for taking the car in originally. Transmission shifting oddly, noisy, or what?

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Yes it is a CVT. I have owned the car for 2 years and have not changed the fluid. I doubt it has been changed.

I also have P0018 code. It was recommended in this forum to get a vacuum test. I asked for a vacuum test. They did a pressure test.

When you took it back, what did explanation did they provide?

Crankshaft Position- Camshaft Position Correlation (Bank 2, Sensor A).

Absolutely nothing to do with transmission vacuum or pressure. You need a much, much better mechanic.
Either a good independent shop or a Subaru dealership. Expect to pay for a diagnosis.

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The OP requested a compression test of the engine, as a result of some problems probably relating to lax maintenance and resulting timing chain problems. Apparently, the mechanic did a manifold vacuum test on the engine, instead.

In any event, neither a compression test or a manifold vacuum test of the engine would have anything to do with a transmission problem.

The flashing AT OIL TEMP light may indicate that there’s a problem with transmission control module.


None have that information was in his post.

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If you had been following his other posts about his car problems, you would have known about that info.

My guess, the flashing transmission fluid over-temp warning light unrelated to prior engine diagnosis, coincidence. Trans problem likely either a faulty temp sensor, transmission electronic controller, or wiring/connector problem.

As far as the original p0018 problem, a compression test or an intake manifold vacuum test, both could be helpful for diagnosing a valve timing problem. The latter is easier to do, so it would make sense to start with that one.

A scan tool would read the trans temp. Good 1st step to figure out issue.

Manifold vacuum might indicate there is a problem but this won’t get you any closer to a diagnosis of the valve timing malfunction. What will you do with the values they provide?

Tell the repair shop that the check engine light is on and you need a diagnosis and estimate of repair. There is a diagnostic procedure for checking the camshaft timing controls.