Trouble codes P0174, P0153 and P0174, lean condition

Tiny
KNIGHTSCHARIOTS
  • MEMBER
  • 2001 FORD ESCAPE
  • 3.0L
  • V6
  • 4WD
  • AUTOMATIC
  • 301,000 MILES
I have two ECM codes present on scan tool p0153 o2 sensor bank 2 sensor 1 and lean code bank 2 p0174. P0153 on scan tool shows confirmed. Scan tool shows unconfirmed for p0174 after changing DPFE sensor and mil light turned off. Have checked for vacuum leaks and exhaust leaks with no leaks present. I'm not convinced the o2 sensor is the cause as fuel trims and voltage specs look normal within range. But at idle in park the vehicle acts like its enriching raising idle and the almost turning off the motor but then recovers to a normal idle. Fuel pressure look good but I'm not sure it the fuel rail damper is operation correctly. What would you advise for further diagnosis and trouble shooting to resolve the lean issue and idle problem. Outside these issues the vehicle runs descent. Thanks in advance for your expertise and help with this matter.
Monday, July 20th, 2020 AT 7:59 PM

7 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Good morning,

The 174 is a lean condition for bank 2 which is the drivers side cylinders. This could be a few things. Check for any vacuum leaks on that side as that will cause this issue.

Remove the oil fill cap with the engine running and put your hand over the top of the tube and see if you feel vacuum. If there is, you have a leaking intake manifold gasket.

https://www.2carpros.com/articles/replace-intake-manifold-gasket

A clogged injector will cause this as well. Adding cleaners has no effect on cleaning. That needs to be done with a tool that injects fluid directly into to the injector for cleaning. If you have a scan tool can you give me the long tern trims for both banks?

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

The 153 is for lean exhaust on bank 2. Once you get the 174 code repaired, the 153 should go away on its own.

Roy

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Wednesday, July 22nd, 2020 AT 5:05 AM
Tiny
KNIGHTSCHARIOTS
  • MEMBER
  • 19 POSTS
Roy: I thought I had this fixed many months ago but the lean demon is back. LTFT bank 1 = 2.3 ( LTFT bank 2 = 23.4 ) I'm leaning towards the fuel injector as the enemy lean condition. The last full scan tool freeze frame details are as follows : calculated load at 48.6% coolant temp 201 STFT bank 1 minus -3.9
LTFT bank 1 2.3
STFT bank 2 26.6 LTFT bank 2 23.4
Engine speed 1973 RPM
vehicle speed 62 MPH. Vehicle has been smoke tested for vacuum leaks at motor, exhaust and evap with no leaks detected or bad deteriorated vacuum hoses found. First threw the p0153 and then a few days later the p0174 was present on scan tool Both codes are confirmed by scan tool. Removed front 3 spark plugs I noticed cylinder 4 piston head was dry and #2 and #6 were showing fuel. So I'm speculating that fuel injector #4 is dirty, intermittent or on its way out. It has a terrible intermittent erratic idle that sometimes almost shuts off the motor and then recovers fast to a normal idle. I'm leaning toward the injector or injectors as I have covered all other diagnostic tree paths. Fuel pump is new and MAF, IAC sensors are good.
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Sunday, June 6th, 2021 AT 3:52 AM
Tiny
ASEMASTER6371
  • MECHANIC
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It is possible but did you do the test with the oil cap removed to verify the intake gasket?

When the smoke test was done, was the oil cap removed to see if there was smoke coming out? You can have a vacuum leak internally into the valley.

Roy
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Sunday, June 6th, 2021 AT 4:23 AM
Tiny
KNIGHTSCHARIOTS
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Yes, checked at oil cap and there was no vacuum present at oil fill cap opening. Intake gaskets have been replaced and are all new. When I smoke tested it had smoke coming out of the oil fill cap when removed. Pulled up dipstick and smoke was coming out of dipstick tube when slightly removed but when in place no smoke leaking out with dipstick in place.
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Monday, June 7th, 2021 AT 8:15 AM
Tiny
ASEMASTER6371
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Okay, that indicates the intake is leaking into the valley if you have smoke out the oil cap.

Roy
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Monday, June 7th, 2021 AT 9:39 AM
Tiny
KNIGHTSCHARIOTS
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  • 19 POSTS
Will re-smoke it and verify a second time to be sure there is smoke coming out of oil filler cap and report the findings back and anything else I find possibly leaking in the valley.
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Monday, June 7th, 2021 AT 4:51 PM
Tiny
ASEMASTER6371
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Correct. If you have smoke in the valley, you have an intake leak.

Roy
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Tuesday, June 8th, 2021 AT 2:41 AM

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