How JustAnswer Works:

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

Ask Autotech58 Your Own Question

Autotech58
Autotech58, ASE Certified Technician
Category: Car
Satisfied Customers: 709
Experience:  38 years experience in the automotive repair industry with experience with many makes and models.
Type Your Car Question Here...
Autotech58 is online now
A new question is answered every 9 seconds

isuzu rodeo s: 1999 isuzu rodeo..only code is p1627 a/d conversion..th

Customer Question

1999 isuzu rodeo..only code is p1627 a/d conversion..the cooling fans constantly run..when i clear code the fans shut off till the engine light comes on..there is a problem with fuel sending unit..but i cut all wires from unit to computer and from computer to cluster..still trips and fans come on...any suggestions?
Submitted: 1 year ago.
Category: Car
Expert:  Autotech58 replied 1 year ago.

To understand why your problem still exists after cutting wires, you need to also understand that cutting wires CREATES circuit failures. The PCM is setting codes and turning the check engine light on to tell you that there is a circuit failure. Cutting the wires does not fix the circuit, but rather, ENSURES that the circuit cannot possibly work. The computer is still programmed to tell you that the circuit is not working....cutting the wires will not change that.

 

When certain circuit failures occur, the PCM is "smart enough" to know that it cannot "trust" the sensors that are supposed to be providing important inputs, so that it will know how to control things properly. So when these failures occur, the PCM is programmed to go into "fail-safe" mode. It will turn the fans on to protect the engine from potential overheating. Since it cannot trust input from it's sensors, it totally ignores them when it goes into fail-safe mode. So it does not know if the engine is really overheating or not and turns the fans on "just in case".

 

The correct "fix" for this is to repair all of the sensor circuits and/or the sensors themselves so that the circuits are functioning as designed. This is the ONLY way to make the computer happy.

Customer: replied 1 year ago.


i under stand..Have replaced pcm..temp sensor..fan relays..why is the code an a/d conversion..i understand limp mode..but i only cut the wires from the fuel level sensor to computer and from computer to dash.and it doesnt trip them codes..the only codes that this has had since its came to my shop was cam sensor and that p1627..replaced cam sensor and i didnt even have to clear that code it cleared itself when i started it..the only codes that has came back was this 1627..then i replaced the computer..(meanwhile gas gauge has been acting up the whole time with the gas light flashing even when it reads empty or full]and relays and temp sensor and check wiring......Im stumped

Expert:  Autotech58 replied 1 year ago.

To be honest, I do not have a really good answer for the P1627 thing, unless the PCM is the wrong PCM for the vehicle. According to the service information for that vehicle, that is not even a valid code. (See the diagram below, which shows a partial listing of possible codes for that vehicle.

graphic

 

Note that the code listings in the service information skip from P1625 to P1635.....

 

I also have no clue what you are referring to when you say "...the code is an a/d conversion.." unless that has something to do with trying to use a "generic" OBD scan tool to try and read "manufacturer-specific" codes. Any code that is listed as "P1xxx" is a "Manufacturer-Specific" code. These have no "set" definitions controlled by the SAE standards, and therefore, generic OBD scanners often cannot render the codes correctly.


The only other thing I know to tell you is to also keep in mind that the PCM shares information with the instrument cluster module. It HAS TO know the fuel level before it can control the EVAP system.....so the fuel level sensor circuit WILL affect PCM operation even though the fuel gauge circuits are not connected to the PCM itself.

 

You will probably have to scan the instrument cluster and repair any and all fault codes there, to keep the PCM happy - due to the fact that these modules share information via the data communications lines.

Customer: replied 1 year ago.


my snap on verus says p1627 pcm a/d malfunction


my mitchell say p 1627 is driver 1 input high voltage


and a/d is analog to digital..if i connect everything the fuel gauge acts up with light flashing..no code for that..just the 1627..if i clear that code the fans shut off fuel gauge appears to work without light flashing then about 20 secs later engine light comes on fuel gauge messes up with light flashing with fans on high speed..only code once again is 1627...with new and old computer...so pretty safe to say that it is not the computer since they both do excact same thing..???

Expert:  Autotech58 replied 1 year ago.
OK hang tight....let me look that up in Mitchell and see if I can make any sense out of this code. I'll get back to you shortly.
Expert:  Autotech58 replied 1 year ago.

OK here is what I come up with....

 

AllData does not list that code at all (we already established that).

When I go to Mitchell, the code is not listed under the DTC Index when you click the link on the right side of the page. However, if I put P1627 into the "Search" in the center section, I come up with the same information that you provided.

 

So, apparently, Isuzu has not released diagnostic and/or repair information for this particular code to the aftermarket....it is a "Manufacturer-Specific" code, so this does not surprise me....

 

However, I was able to go one step further:

 

I am a sponsor member of iATN and have the resources available from professional automotive technicians around the world.....When I checked their "known Fixes" database, I found several listings for this same code, with the same symptoms you are describing....Cooling fans that will not shut off and a fuel level gauge and light that is extremely erratic.

 

Although there was about 20 listings for this same issue, I only read through three of them before coming to this conclusion:

 

In all three of the listings that I read (I picked them at random), replacing the fuel level sending unit fixed the problem. So it would be safe at this point to assume that code P1627 IS for the fuel level sender circuits. Makes sense to me now....an ANALOG sensor signal that must be converted to DIGITAL in order to share among different modules.

 

So at this point, I can only refer you back to my original post where I stated:

 

"The correct "fix" for this is to repair all of the sensor circuits and/or the sensors themselves so that the circuits are functioning as designed. This is the ONLY way to make the computer happy."

 

Repair the fuel level sensor circuits.

 

Let me know if I can do anything else for you.

Customer: replied 1 year ago.


i want my money refunded..read what ur tech sent me..i answered the question before he did...he shoulda told me that the fuel level sensor was related to that code...he didnt say that till i told him..and i found it threw the internet..ty john..3308120177

Expert:  Autotech58 replied 1 year ago.

Umm....Pardon me???

 

You NEVER told me that this code was for your fuel level sensor circuits. In fact, you spent your time on this post DENYING that the code in question had anything to do with the fuel level sensor circuits. You continued to INSIST that this code was NOT due to a fuel level sensor problem, even after I had told you not once, but TWICE that you needed to repair these circuits.....the first time being in my ORIGINAL post.

 

"..i understand limp mode..but i only cut the wires from the fuel level sensor to computer and from computer to dash.and it doesnt trip them codes.."

 

"..if i connect everything the fuel gauge acts up with light flashing..no code for that..just the 1627.."

 

 

You might try to remember what you said, or even better, "re-read" this thread yourself before making such non-factual and totally unmerited claims, in an effort to avoid having to pay for the services that have been delivered in good faith on your behalf .

 

It would probably be much better for both of us to stick to the facts as they appear on the page. Please keep in mind that anyone else reading this thread can read the ENTIRE conversation in its full context....

 

Just as a customer is not automatically relieved of having to pay for diagnostic time in an auto repair shop because a similar diagnosis is also available at a different shop location, neither should a customer be not held accountable for paying for the information asked for, and subsequently provided for him, on a pay web site, simply because similar information may also be available on a different web site.


Yes, you probably will get your refund if you take this up with customer service and insist on it. However, you should also consider that unlike most of the open forums around the internet, PERSONAL INTEGRITY can go a long way on this web site. You just might need some professional assistance again in the future. I do not believe your latest actions here would be very beneficial in helping you get it.

 

....just in case you would like to "re-think" this one.....

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:

 
 
 
  • 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 P Elm City, NC
< Last | Next >
  • 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 P Elm 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. Phil Marysville, CA
  • Lurch. Thank you very much. I had real doubts about this website but your promptness of response, quick followup and to the point answer with picture was incredible. Charles Walnut Creek, CA
  • As a single woman, I really appreciate an excellent and affordable opinion.
    Thank you Geordie, I will not hesitate to contact justanswer in the future!
    Sue Charleston, WV
  • Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, Frank...you do indeed know your stuff. Jim Castleberry, FL
  • The nearest Volvo dealer is 160 miles away. Best $15 bucks I have spent in a long time! Paul M Corpus Christi, TX
 
 
 

Meet The Experts:

 
 
 
  • Chris (aka-Moose)

    Technician

    Satisfied Customers:

    846
    16 years of experience
< Last | Next >
  • http://ww2.justanswer.com/uploads/MU/muddyford/2012-6-13_1204_1.64x64.png Chris (aka-Moose)'s Avatar

    Chris (aka-Moose)

    Technician

    Satisfied Customers:

    846
    16 years of experience
  • http://ww2.justanswer.com/uploads/TE/TedG/2012-6-15_14759_avaLarge.64x64.jpg Ted G.'s Avatar

    Ted G.

    ASE Certified Technician

    Satisfied Customers:

    1596
    20 years auto repair experience, ASE Master Tech, Mechanical Failure consultant, Expert Witness
  • http://ww2.justanswer.com/uploads/joecamel90/2008-11-13_03615_head_shot.jpg George H.'s Avatar

    George H.

    ASE Certified Technician

    Satisfied Customers:

    1311
    ASE Master Tech 15+ yrs, AAS Automotive Technology, Factory trained Asian specialist
  • http://ww2.justanswer.com/uploads/AM/amedee/2013-10-24_23656_Amedee1.64x64.jpg Amedee's Avatar

    Amedee

    ASE Master Tech

    Satisfied Customers:

    2367
    ASE Master Tech advanced level specialist
  • http://ww2.justanswer.com/uploads/SU/supermechanic/2013-8-23_03546_500.64x64.jpg Jerry's Avatar

    Jerry

    Master Mechanic

    Satisfied Customers:

    1906
    ASE master, 30+ years. All makes and models. Trouble shooter, shop forman, service manager
  • http://ww2.justanswer.com/uploads/CR/crzydrvr00/2013-11-3_12123_246347.64x64.jpg Richard's Avatar

    Richard

    ASE Certified Technician

    Satisfied Customers:

    942
    12 years Ford Lincoln/Mercury Jaguar dealership as a technician and shop foreman reparing all makes
  • http://ww2.justanswer.com/uploads/ST/Steve7654/2012-6-5_215929_japic800x660.64x64.jpg Steve's Avatar

    Steve

    Auto Service Technician

    Satisfied Customers:

    1980
    25+ yrs experience as a professional working technician; ASE L1 master technician