'96 850 Check Engine Light

JonTechno · Post by **JonTechno** » 28 Jan 2019, 06:19

1996 Volvo 850 2.5L Automatic. 175K ish miles (Odometer intermittent). I used a Matco Scan Tool to pull the codes. 2 are shown:

PO172
P0440

Looked them up, not sure how to continue diagnosing problems.
All help or recommendations welcome and appreciated

Sommerfeldt · Post by **Sommerfeldt** » 28 Jan 2019, 06:59

Hello!
Both of those point to a vacuum leak in my mind, at least. Check your hoses and replace. For the 0440, it can be an idea to go over all hoses and fittings in the evap system, and also replace the valve.

- S

WhatAmIDoing · Post by **WhatAmIDoing** » 29 Jan 2019, 08:22

In my experience, P0172 is always caused by a severe vacuum leak. Check your vacuum lines. With the engine running, you might be able to hear a wooshing or hissing sound to help you track down the leak. What rpm does it idle at?

P0440 is usually the J and L hose on the charcoal canister. Replacing the lines on the evap system may solve your P0172.

JonTechno · Post by **JonTechno** » 29 Jan 2019, 11:26

Thanks, I'll have to check the hoses for leaks, as well as the J and L hoses.

Engine idles at 1,000 RPM

Post by **misha** » 29 Jan 2019, 11:36

Non turbo with auto transmission and in "D" idles at 1000rpm.
While in P or N it will be around 900rpm.
N/a manual around 900...Turbos a bit lower...around 800+-50.