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2015 SE throws code P2195 - Vacuum Leak?


New Member
United States
What I Drive
2015 Ford Focus SE
My wife was complaining her car was running a bit rough, and now it's thrown a P2195 code. That's O2 sensor signal biased/stuck lean bank 1 sensor 1. No worries you say, replace the sensor. Trouble is the car did exactly this about 8000 miles ago and I replaced the sensor then with a new OE Bosch sensor. I'm digging deeper this time and looking at the live data. I see the O2 sensor voltage oscillating, which I consider normal, and the short term fuel trim is high at idle, in the 20% range, but drops to near zero at higher RPM. I suspect a vacuum leak, but was unable to find one by spraying the various visible joints in the dreaded plastic intake manifold with throttle body cleaner, trying to find a spot that, when sprayed, gives me a change in idle speed. I didn't get underneath, however.

Are these plastic manifolds on the 2 liter prone to cracking, warping or leakage? Are there any other common leakage points to check? For giggles, I cleaned the MAF sensor (with CRC MAF sensor cleaner) and throttle body (with CRC throttle body cleaner) since this has never been done, and put the intake snorkel hose back on securely. Still the same trouble with the short term fuel trim, although the cleared code has not returned yet.

2015 Focus SE 2 liter naturally aspirated, 5 speed, 92,000 miles. Thanks in advance.

Handy Andy

Well-Liked Member
Premium Account
Grand Rapids
United States
What I Drive
2018 Ford Fiesta SE HB
When your engine runs rough - that engine, how does the exhaust smell?

If exhaust is LEAN - you don't have any true sense of unburned fuel to smell

Rough running engines exhaust usually means also a misfire - which would smell of raw or heavy odor of fuel in the fumes.

Now the issue of sensor, how is the Catalytic? Is it ok? Undamaged? Is it Doing its job of taking otherwise stinky exhaust and making it more tolerable?

The "Lean" condition can also be from EGR issues but since this thing is a 5-speed and has got over 92,000 Miles - it's more than likely a problem with the GDi-type of fuel system (which is Gas Direct Inject) where the injector is in the TOP of the cylinder - In the cylinder head.
  • IT may be plugged or carboned up so the fuel spray into the cylinder is not the best vaporous mist. A combustion chamber problem.
    • Have you tried a fuel system cleaner, or something called Regane? Might want to try that - or just need to run a premium fuel for a tankful and use it on highway miles above 50mph so the hotter cylinder head heat and the exhaust system can clean and clear out some of this mess
    • - once that is done and the engine still runs rough - it'll need more TLC including a verify (inspect) and even a plug change - that the spark plugs are not fouling out or cracked. Haven't heard from you about those...it's getting close to their time. The plugs and their condition would show which gasket (per cylinder) is leaking or if there is even a vacuum leak or other condition causing this.
    • Forgive the redundancy, the service history questions need to be asked to know how the condition came to be.
      • In "Vacuum leak" issues, many focus on the intake, which yes, it does make sense, but when the attempts to locate such leaks - they can't be found - many don't realize that the PCV valve hose or the exhaust manifold can cause poor vacuum issues that are overlooked.

It's a good idea to spray around those known areas where air can get in - if it's not leaking oil or at least not burning it - it's a good sign to know it is still healthy.

Other things to check:

I might be wise to check the exhaust manifold and its condition - a small leak can turn into a major vacuum leak of air returning to the system instead of thru the exhaust pipe - leaning out an engine in itself knowing it will need to run lean during deceleration changing the way the O2 sensor registers Lean.
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