Ford

Have Ford Questions? Ask a Mechanic for Answers ASAP

Ask an Expert,
Get an Answer ASAP!

Ford

P0174 FORD WINDSTAR REPLACED MAF SENSOR LIGHT STILL ON

Customer Question
P0174 FORD WINDSTAR REPLACED MAF SENSOR LIGHT STILL ON
Submitted: 7 years ago.Category: Ford
Ask Your Own Ford Question
Answered in 2 minutes by:
4/4/2010
Ford Mechanic: Richard, ASE Certified Technician replied 7 years ago
Richard
Richard, ASE Certified Technician
Category: Ford
Satisfied Customers: 15,574
Experience: 12 years at a Ford Lincoln/Mercury and Jaguar dealer as a technician and shop foreman.
Verified

 

Hello and welcome to justanswer.com

 

What year is your Windstar and which engine do you have? How is your van running? Is this the only code?

Ask Your Own Ford Question
Customer reply replied 7 years ago
GOT NO ANSWER. FORD WINDSTAR CODE P0174. REPLACED MAF SENSOR, CLEARED CODES. DROVE AROUND FOR A FEW MINUTES LIGHT CAME BACK ON
Ford Mechanic: Richard, ASE Certified Technician replied 7 years ago
The usual cause is a vacuum leak. On the 3.8 liter engine I see issues with the intake manifold seals and the port bolts. If your scan tool can read pids or live data monitor the fuel trims to see if they are high (greater then 7%).
Ask Your Own Ford Question
Customer reply replied 7 years ago
READ PIDS. ALL ARE AT ACCEPTABLE LEVELS NOTHING HIGHER THAN 6% REPLACED INTAKE MANIFOLD GASKETS SEALS AND PORT BOLTS. REPLACED EGR VALVE, FUEL FILTER, FUEL PUMP, ECM, CHECKED AND RECHECKED ALL VACUUM LINES AND PCV VALVE....HELP ME OUT
Customer reply replied 7 years ago
2000 FORD WINDSTAR 3.8. P0174 IS THE ONLY CODE THAT KEEPS COMING BACK
Customer reply replied 7 years ago
Relist: Answer quality.
need a more incisive answer...half ass answers are not acceptable.
Ford Mechanic: Richard, ASE Certified Technician replied 7 years ago

The lean codes is almost always caused by unmetered air. On your van it's usually the valve cover, fuel regulator hose, intake seals and port bolts as well as a PCM reflash. Ok I think we should start by clearing the keep alive memory which you may be able to do with your scan tool or you can just disconnect the battery. Also let me know the year and if you have the 3.8 liter. Next start the engine while monitoring the fuel trims and oxygen sensors. Try spraying some carb cleaner around the intake looking to see if the trims lower or go into the negative. You can also try to smoke leak test the intake. Here is the test we use.

 

TSB 04-17-4

09/06/04

MALFUNCTION INDICATOR LAMP (MIL)
ILLUMINATED - SYSTEM LEAN DIAGNOSTIC
TROUBLE CODES (DTC'S) - SERVICE TIPS

 

FORD:
2000 Contour
2000-2002 Escort
2000-2003 Escort ZX2
2000-2004 Crown Victoria, Focus, Mustang, Taurus
2002-2004 Thunderbird
2000-2003 Windstar
2000-2004 Econoline, Excursion, Expedition, Explorer, F-Super Duty, Ranger
2001-2004 Escape
2004 Freestar
2000-2004 F-Series

 

LINCOLN:
2000-2002 Continental
2000-2004 LS, Town Car, Navigator
2002-2003 Blackwood
2003-2004 Aviator

 

MERCURY:
2000 Mystique
2000-2002 Cougar
2000-2004 Grand Marquis, Sable, Mountaineer
2004 Monterey

 

ISSUE

This article is intended to aid in diagnosing DTC's P0171, P0174, P1130, P1131, P1150, P1151, P2195, or P2197 (system lean or lack of HEGO switches) when a vacuum leak is present. HEGO sensors, MAF sensors, and PCM replacements are not an effective repair when a vacuum leak is causing the above DTC's.

ACTION

Perform the following inspections/repairs when the above codes are found in memory. Procedure provides instructions on how to make comparisons of the total fuel corrections (using scan tool or equivalent) at idle and high RPM's to help determine if a vacuum leak is the root cause of the DTC's.

SERVICE PROCEDURE

NOTE FREEZE FRAME AND ADAPTIVE FUEL VALUES (ASSOCIATED WITH "LONGFT" PID) WILL NOT BE AVAILABLE IF A KAM OR OBDII RESET WAS RECENTLY PERFORMED.

 

NOTE FREEZE FRAME DATA WILL INDICATE THE ENGINE AND AMBIENT CONDITIONS WHEN THE DTC WAS SET. THESE ARE IMPORTANT BECAUSE THE VACUUM LEAKS MAY OCCUR ONLY WITHIN SPECIFIC TEMPERATURE RANGES AND MUST BE DUPLICATED TO DETECT THE LEAK.

 

NOTE FUEL TRIMS AT IDLE ARE PARTICULARLY SENSITIVE TO VACUUM LEAKS SINCE THE UN-METERED AIR "LEAKAGE FLOW" IS A HIGHER PERCENTAGE OF TOTAL AIRFLOW AT IDLE THAN AT PART THROTTLE. THE BAROMETRIC PRESSURE (BP) PID IS NOT RECOMMENDED TO VIEW WHEN DIAGNOSING A VACUUM LEAK. BP IS AN INFERRED PID CALCULATED DURING HIGHER ENGINE LOADS.

 

1.Perform preliminary inspection, retrieve and record DTC's and Freeze Frame Data. DO NOT PERFORM KAM RESET OR OBDII RESET (CLEAR CODES) AT THIS TIME, ADAPTIVE FUEL TABLES MUST BE INTACT FOR THIS PROCEDURE.

 

a.If DTCs are continuous, or if other DTC's or drive symptoms are present other than at idle, diagnose and repair those codes/symptoms first.

 

b.Perform visual inspection - look for disconnected/broken/cracked vacuum hoses especially near vacuum trees. Check PCV elbows for cracks or loose connection. Confirm vehicle has the correct PCV valve installed. If a suspect vacuum leak is found proceed to Step 4.

 

NOTE EACH VEHICLE APPLICATION REQUIRES A PCV VALVE CALIBRATED FOR THAT VEHICLE. MOTORCRAFT PARTS ARE STRONGLY RECOMMENDED. ALSO, THERE WILL BE A NORMAL VARIATION IN FUEL TRIMS FROM VEHICLE TO VEHICLE.

 

2.Determine if vacuum leak is present.

 

a.Set up scan tool to monitor the following PIDS: ECT/CHT, LONGFT1, LONGFT2, SHRTFT1, SHRTFT2, IAT.

 

b.Start the engine and run at idle with all accessories off - gear lever in Neutral/Park.

 

c.Run engine until ECT/CHT matches the corresponding freeze frame data from Step 1. This will duplicate the customer's engine operating temperatures when the DTC was set in memory. Hood may remain open during this test to help reduce ECT/CHT/IAT temperatures. Keep IAT below 115°F (46°C).

 

d.Record LONGFT's and SHRTFT's.

 

NOTE TO PREVENT HIGH ECT/CHT AND IAT TEMPERATURES IT MAY BE NECESSARY TO PERFORM THIS TEST WITH THE ENGINE RUNNING FOR SHORT INTERVALS, ESPECIALLY WHEN AMBIENT TEMPERATURE IS ABOVE 85°F (29°C). USE OF A GARAGE FAN WILL HELP TO KEEP ENGINE TEMPERATURES STABILIZED DURING TEST. IT MAY BE NECESSARY TO RUN THIS TEST AT SPECIFIC ECT/CHT/IAT TEMPERATURES, REVIEW FREEZE FRAME DATA. EXAMPLE: IF ECT WAS AT 160°F (71°C) THEN ENGINE MAY NEED A COLD START TO DUPLICATE THIS TEMPERATURE.

 

e.Determine total fuel correction at idle for an in-line 4 cylinder engine or bank 1 of a V-engine by adding LONGFT1 to SHRTFT1. Determine total fuel correction for bank 2 of a V-engine, by adding LONGFT2 to SHRTFT2.

 

NOTE MAKE SURE ONLY THE CORRECT BANKS AND TRIMS ARE ADDED TOGETHER (DO NOT ADD LONGFT1 TO LONGFT2 OR LONGFT1 TO SHRTFT2.)

 

^EXAMPLE 1: BANK1 LONG FUEL TRIM; LONGFT1 = +13% AND SHORT FUEL TRIM; SHRTFT1 = +23%. THE TOTAL CORRECTION ON BANK1 IS +36% (13% +23% = 36%).

 

^EXAMPLE 2: BANK2 LONGFT2 = +24% AND BANK 2 SHRFT2 = -3%. THIS TOTAL FUEL CORRECTION ON BANK 2 IS +21% (+24% -3% +21%.).

 

A TYPICAL VACUUM LEAK WHICH MAY SET A LEAN CODE DTC WILL HAVE TOTAL CORRECTION OF AROUND +20% OR GREATER AT OR NEAR IDLE (DEPENDS ON CALIBRATION)

f.Depress and hold throttle pedal to maintain an engine RPM of 2500.

 

g.Observe PIDS with engine RPM at 2500. View and record LONGFT1, LONGFT2, SHRTFT1 SHRTFT2. Do not hold engine RPM's at 2500 for more than 20 seconds. Release pedal and repeat if more time is necessary to record PIDS.

 

h.Determine total fuel correction at 2500 RPM's by adding the LONGFT's to the associated SHRTFT's.

 

I.If the fuel correction decreases, more than 15%, (example: was +31% at idle on bank 1 but changed to +12% at 2500RPM on bank 1, a decrease of 19%) then a vacuum leak is most likely causing the lean diagnostic test codes. Proceed to Step 3.

 

j.If the total correction remains approximately the same then the lean condition is not caused by a vacuum leak. Refer to the PC/ED for further diagnostics.

 

3.Pinpointing vacuum leaks.

 

a.Monitor SHRTFT's with scan tool with engine running at idle.

 

b.Locate vacuum trees off air induction system and PCV system. Use hose clamp or pinch off pliers (avoid tools with sharp edges).

 

NOTE USE CAUTION WHEN CLAMPING HOSES. A VACUUM CAP OR EQUIVALENT CAN ALSO BE USED TO BLOCK THE VACUUM SOURCE TO A SPECIFIC SYSTEM. DO NOT TRY TO PINCH OF A HARD PLASTIC HOSE OR CONNECTION, TRY ISOLATING BY CAPPING. CLAMPING OF THE FUEL SYSTEM PURGE HOSE MAY SHIFT SHRTFT DURING PURGING MODES, USE VISUAL INSPECTION ON THIS HOSE IF RESULTS ARE NOT CONSISTENT.

 

c.Observe short fuel trims when pinching specific vacuum lines. The SHRTFT values should decrease more than 15% towards the negative direction, if a vacuum leak was pinched off. (wait up to 20 seconds to observe if pinch has any effect on SHRTFT's).

 

NOTE EXAMPLE: PINCH OFF THE BRAKE BOOSTER VACUUM HOSE (DO THIS ONLY IN PARK) AND OBSERVE SHRTFT'S. IF THE SHRTFT'S DECREASES, BY MORE THAN 15%, A VACUUM LEAK IS PRESENT. IF THE SHRTFT1 WAS AT +14% BEFORE PINCHING THEN SHIFTS TO -7% AFTER PINCHING, TOTAL SHIFT OF 21% TOWARDS NEGATIVE DIRECTION.

 

d.If vacuum leak is located proceed to Step 4c.

 

NOTE INTAKE GASKETS OR MANIFOLD LEAKS CANNOT BE DETECTED BY PINCHING OFF LINES. USE OTHER LEAK DETECTION METHODS, SUCH AS SMOKE TEST, SONIC TESTS, AND PROPANE.

 

e.If no vacuum leaks are found, refer to the PC/ED for further diagnostics.

 

4.Verification of repair.

 

a.Prepare scan tool and vehicle to monitor short term fuel trims (SHRTFT's).

 

b.Get vehicle into stabilized idle condition, unless freeze frame indicates other temperatures.

 

c.Repair vacuum leak.

 

d.SHRTFTs should decrease by at least 15%. If they do not, return to Step 2.

 

e.Clear KAM and codes.
Ask Your Own Ford Question
Ask Richard Your Own Question
Richard
Richard
Richard, ASE Certified Technician
Category: Ford
Satisfied Customers: 15,574
15,574 Satisfied Customers
Experience: 12 years at a Ford Lincoln/Mercury and Jaguar dealer as a technician and shop foreman.

Richard is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

AlvinC answered a question about my Ford truck that only someone with an in-depth knowledge of his subject would have known what was going on.

Rich DUSA

Because of your expertise, you armed me with enough ammunition to win the battle with the dealer. They are installing a fuel filter and fuel pump at no charge to me.

MollyUSA

I needed help with my car on Saturday morning....got a response in 5 minutes, and it was the perfect solution. Thanks again to your service.

Jason V.Kirkland, WA

I do know, after going though this with JustAnswer, that I can somewhat trust my mechanic but I will always contact you prior to going there.

BRNew Jersey

I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry.

Stephanie PElm City, NC

used your service this weekend with "Trecers" help. thank you ,thank you, thank you. replaced an A/C fan motor. Local Auto Zone had part. $15.00 "tracer" fee and $40.00 for parts, I saved several hundreds of dollers at a shop. i will recommend you and use you in the future.

David L.Richmond, TX

9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much.

PhilMarysville, CA

< Previous | Next >

Meet the Experts:

Ron

Ron

ASE Certified Technician

24,155 satisfied customers

23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs

Chris (aka- Moose)

Chris (aka- Moose)

Technician

27,937 satisfied customers

16 years experience

John Mc

John Mc

Ford Technician

5,495 satisfied customers

19 years Ford Lincoln Mercury experience

Chuck

Chuck

ASE Certified Technician

1,685 satisfied customers

33 Years Experience,Ford Senior Master,ASE Master,L1 Advanced Engine Performance

Cam

Cam

Journeyman Automotive Technician

10 satisfied customers

GM Grand Master Technician 2007. 14 years Automotive experience.

Richard

Richard

ASE Certified Technician

15,574 satisfied customers

12 years at a Ford Lincoln/Mercury and Jaguar dealer as a technician and shop foreman.

Mike V.

Mike V.

Auto Service Technician

1,335 satisfied customers

25 years experience on all makes and models, Licensed NYS Inspector.

< Previous | Next >

Related Ford Questions
Leak antifreeze on top of engine. They are old but wont hold
leak antifreeze on top of engine JA: How old are the hoses? And have you tested the actual mix of your coolant? Customer: they are old but wont hold water JA: What is the model/year of your Ford? Cust… read more
Jaybird61
Jaybird61
Master Automotive Mechanic
1,886 satisfied customers
Car runs well, engine purrs, so don't think it's an engine
Car runs well, engine purrs, so don't think it's an engine efficiency issue. Odometer typically always showed approximately 390-410 miles to empty when gas tank was filled up. All of a sudden, it only… read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
27,937 satisfied customers
I believe that i need to replace the engine coolent
i believe that i need to replace the engine coolent temperature switch on a 2008 f-250 6.4 powerstroke and need to know where it is and how to get to it … read more
Ron
Ron
ASE Certified Technician
Vocational, Technical or Trade Scho
24,155 satisfied customers
My engine is a 70 302, was a 2bbl carb, now a 4bbl. engine
my engine is a 70 302, was a 2bbl carb, now a 4bbl. engine fires great, but after driving awhile, it wants to stall at idle slow braked … read more
heavy_chevy_396
heavy_chevy_396
Vocational, Technical or Trade Scho
2,518 satisfied customers
Are you able to provide quick help for engine not turning
Hi, are you able to provide quick help for engine not turning over? … read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
27,937 satisfied customers
Temp gauge spikes (quickly) but engine is not overheating.
Temp gauge spikes (quickly) but engine is not overheating. Turning off ignition for a few seconds resets the gauge -- but it may spike again in a few minutes or in two weeks! It's always an adventure.… read more
Ron
Ron
ASE Certified Technician
Vocational, Technical or Trade Scho
24,155 satisfied customers
Engine was cleaned and afterwards car started to run rough
Engine was cleaned and afterwards car started to run rough and then service engine light came on Scanned it and has P1151 code … read more
Ron
Ron
ASE Certified Technician
Vocational, Technical or Trade Scho
24,155 satisfied customers
Service engine light just came on and engine stalls at an
Service engine light just came on and engine stalls at an idle … read more
Dan
Dan
Automotive Technician
Vocational, Technical or Trade Scho
25 satisfied customers
Engine will spin but it won't start. No there's no
engine will spin but it won't start JA: Have you checked the battery, particularly the terminal connections? Are they corroded? Customer: no there's no corrodison JA: What is the model/year of your Fo… read more
Kenny Z
Kenny Z
Ford Senior Master Technician
High School or GED
16 satisfied customers
2006 f 350 have to rev engine high to keep engine from
2006 f 350 have to rev engine high to keep engine from stalling when engaging clutch. Clutch does not engage smooth … read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
27,937 satisfied customers
2012 FordFusion - start engine in park horrible jet engine
2012 FordFusion - start engine in park horrible jet engine roar starts I'm so scared I turn off car. Checked at ford dealer. No history found. I can't drive it from my terror. Husband has driven it wi… read more
eauto
eauto
self employed
High School or GED
74 satisfied customers
Replace the gas engine on a 2004 ford escape hybrid. Engine
replace the gas engine on a 2004 ford escape hybrid … read more
Eric
Eric
Retired
N/A
14,436 satisfied customers
The check engine light came on, It stays on. It was on at
We have gone to a service centre and told they could not look at it until probably Tuesday next week. We are travelling and away from home. … read more
Ron Z.
Ron Z.
Vocational, Technical or Trade Scho
2 satisfied customers
Coolant leaks at rear of engine. Engine not run for last
coolant leaks at rear of engine. Engine not run for last several days so no pressure in engine. … read more
heavy_chevy_396
heavy_chevy_396
Vocational, Technical or Trade Scho
2,518 satisfied customers
6 Bucs 2012 f250 6.7 engine. truck has the check engine on,
6 Bucs 2012 f250 6.7 engine. truck has the check engine on, and the following codes. P20BA, P026A, P0087. I changed fuel filters and drove the truck from 0 to 70mph it picks up and works fine, let spe… read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
27,937 satisfied customers
2011 F150, rebuilding engine 3.5 ecoboost. Engine started
2011 F150 , rebuilding engine 3.5 ecoboost. Engine started well and ran very smooth. After several minutes run, oil pressure dropped off at idle. Low oil pressure warning comes on, If RPM's increase, … read more
HDGENE
HDGENE
Master Technician/Lead Technician
Associate Degree
2,835 satisfied customers
Stopped for gas, when i started the engine the check engine
stopped for gas, when i started the engine the check engine light came on and the air conditioning stopped cooling. Noticed that the engine idled rough and slower, stalled a couple of times. suspect t… read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
Engine shut down driving in a heavy rain storm. Engine
engine shut down driving in a heavy rain storm. Engine cranks doesn't start. water in fuel and fuel filter show on dash panel while cranking engine. … read more
HDGENE
HDGENE
Master Technician/Lead Technician
Associate Degree
2,835 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x