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 Dan Your Own Question

Dan
Dan, Technician
Category: Jeep
Satisfied Customers: 21392
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
Type Your Jeep Question Here...
Dan is online now
A new question is answered every 9 seconds

Jeep Grand Cherokee: I get fault code 27 on my 1994 Jeep Grand

Customer Question

I get fault code 27 on my 1994 Jeep Grand Cherokee. What should I do to fix it? I replaced the injectors but no change.
Submitted: 2 years ago.
Category: Jeep
Expert:  Brad replied 2 years ago.

Brad :


Hello and welcome to JustAnswer, My name is XXXXX XXXXX X will be assisting you


Brad :

Ok, since you have replaced half of the injectors you should Ohm the rest of them with Ohm-Meter..a good reading is around 14.5 Ohms... If its way out, replace that injector...

Brad :

Code 27 Injector control circuit

Brad :

Injector output driver does not respond properly to the control signal.

Brad :

if you have anymore questions just ask..

Brad :


Well I want to Thank You for choosing JustAnswer. It was my pleasure assisting you, and if you have any future questions feel free to Request me


http://www.justanswer.com/car/expert-dodgetech77/ Thank you and have a greatday!!!!! Brad

Expert:  Brad replied 2 years ago.
What Happens Now?

Your chat has ended, but you can still work with your Expert to get an answer to your question if you have not yet received one.

Come back to this page at any time to see additional information from your Expert.  You will also receive an email when your question is updated.  If you want to send a message to your Expert, use the box below.

If you have already received a satisfactory answer to your question, click the Accept button above.  Experts are credited for each accepted answer they provide.
Customer: replied 2 years ago.
I have ohmed all the injectors they were all within specs.
Expert:  Brad replied 2 years ago.
Ok, here is the issue... The code 27 is a generic code saying that Injector control circuit Injector output driver does not respond properly to the control signal. In order to continue diagnostics we need to norrow that down... If you can get it scanned at a Advanced Auto or Autozone they will give you another code that will tell us which cyl is causing the problems.. When you get that info I will be able to assist you more... Because right now we will be checking all of the injectors and doing alot of unnessassary testing... Get the code and reply back and we can go from there...
Customer: replied 2 years ago.
OK I will tryto get it scanned tomorrow. I can tell you that with the engine running unpluging injector 1, 2 or 3 has no effect on it. Unplugging 4, 5, or 6 each will kill the engine.
Expert:  Brad replied 2 years ago.
Expert:  Brad replied 2 years ago.
There is wiring, and all 1-2-3 injectors are all on separate circuits... Get that code and we will go from there
Customer: replied 2 years ago.
We don't have Advanced Auto in our area and AutoZone says they do not do OBD 1 scans. Any suggestions??
Expert:  Brad replied 2 years ago.
Ok, if you cant get the codes read.. Then you will need to check all the injectors... Measure the green wire.. It should be 12v on all Injectors... Then take the a testlight and attach the clip to Positive on battery and check the other wire on all Injectors,,, It should flash while its running for all them... Let me know what you find
Customer: replied 2 years ago.
All injector green wires have 12v, all injector other wires flash as they should.
Expert:  Brad replied 2 years ago.

And you said that you have checked the injectore and replaced the PCM... Was it a new PCM?

 

Customer: replied 2 years ago.
No it was not a new PCM. The fault code 27 was not there when I first installed it. It came after I had run the engine for a while.
Expert:  Brad replied 2 years ago.

Well if the Injectors are within spec, and wiring is good.. It will have to be PCM.. Why was PCM the first time?

 

Customer: replied 2 years ago.
Why was PCM the first time? I don't understand your question. I replaced the original just as a shot in the dark. Obviously that was not the problem.
Expert:  Brad replied 2 years ago.
Ok, just making sure that you was replacing the PCM trying to fix this issue... Ok, you said that unplugging 1-2-3 doesnt make any effect on your engine.. But unplugging 4-5-6 will shut engine off.. That means that 1-2-3 arent working.. and you said for sure the green wire has 12v.. And you tested the other wire for ground by clipping test light on Battery + Positive and the other wires are flashing? If so the injectors arent working.. But you said you replaced 1-2-3 injectors.. Can you swap 1-2-3 with 4-5-6- and see what happens? Id like to see if they fire on them cylinders
Customer: replied 2 years ago.
OK I'll give it a try. Do I need to replace both injector grommets each time I take them out?
Customer: replied 2 years ago.
I swapped the injectors everything still the same. When I unplugged 1 or 2 nothing happened.
Expert:  Brad replied 2 years ago.
Ok, If that is the case then for sure something is wrong with wiring.... If you took 1-2-3 and swapped it with 4-5-6 and 4-5-6 are working fine... Then yes there is a wiring or PCM issue... What I dont understand is why they are flashing correctly
Customer: replied 2 years ago.
What's next?
Expert:  Brad replied 2 years ago.
If what you are telling me with the wires and injectors, then the next step is to replace the PCM with a new one... The injectors only have 2 wires.. the Green is shared 12v with all injectors and the other is Injector driver circuit directly from PCM....
Customer: replied 2 years ago.
You think both PCM's I have are defective? A new PCM is $250-400. I don't have much confidence that will cure the problem.
Expert:  Dan replied 2 years ago.

Welcome to JustAnswer, my name is XXXXX XXXXX X'm here to help get your problem resolved. Ask follow up questions, thanks. Considering PCM has been replaced and injectors have been tested it sounds like a wiring problem between pcm and injectors. Use a LED testlight to see if each injector has good ground pulse..Whatever one doesnt have ground pulse test wiring between that injector and PCM for shorted/open circuits..If good replace pcm..If shorted or open run new wires or replace harness. Check the splice A-142, at the rear of the wiring harness that runs next to the valve cover, for poor connection on injector feeds..Here is a wire diagram to help with testing and troubleshooting instructions for injector 2..troubleshooting will be the same for each injector just on diffferent wires. Let me know if you have questions, thanks.

 

 

 

http://db.tt/1Sp7r8T

 

http://db.tt/nB4SMejE

Dan, Technician
Category: Jeep
Satisfied Customers: 21392
Experience: Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
Dan and 8 other Jeep Specialists are ready to help you

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:

 
 
 
  • Thank you so much for your answer. My initial estimate was $325; I got it done for $100 - part and labor. Lynn B. Ormond Beach, FL
< Last | Next >
  • Thank you so much for your answer. My initial estimate was $325; I got it done for $100 - part and labor. Lynn B. Ormond Beach, FL
  • I was skeptical at first but thought I'd give it a try. I was pleasantly surprised. Your site actually is a quality service that I would recommend to others in a heartbeat. Stan Sayre, PA
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
 
 
 

Meet The Experts:

 
 
 
  • Mark

    22 Year Factory trained technician

    Satisfied Customers:

    2548
    Jeep factory training........25 years in the industry.
< Last | Next >
  • http://ww2.justanswer.com/uploads/MO/MoparCertified/2012-6-7_4142_mechanic.64x64.jpg Mark's Avatar

    Mark

    22 Year Factory trained technician

    Satisfied Customers:

    2548
    Jeep factory training........25 years in the industry.
  • http://ww2.justanswer.com/uploads/jeep10000/2008-9-18_222938_192601.jpg Chris's Avatar

    Chris

    Shop Foreman

    Satisfied Customers:

    2265
    Jeep and ASE Certified Master Tech
  • http://ww2.justanswer.com/uploads/ke4ich/2009-08-12_212931_DSC02211.JPG moparfl's Avatar

    moparfl

    ASE Certified Technician

    Satisfied Customers:

    1128
    ASE Master Tech Chrysler Dodge Jeep Master Tech
  • http://ww2.justanswer.com/uploads/nvltgo/2010-10-18_211525_youranswers.jpg Dave's Avatar

    Dave

    Jeep Master Tech

    Satisfied Customers:

    1120
    Chrysler Triple Master, ASE master Tech AA degree in Auto.
  • http://ww2.justanswer.com/uploads/tsmodie/2009-6-10_144056_tim.jpg Tim Mohr's Avatar

    Tim Mohr

    ASE MASTER TECH

    Satisfied Customers:

    805
    30 YRS EXPERIENCE, FOREIGN AND DOMESTIC, GAS AND DEISEL
  • http://ww2.justanswer.com/uploads/CD/CDJMastertech/2012-6-9_201455_JustAnswerProfilelarger.64x64.JPG CDJMasterTech's Avatar

    CDJMasterTech

    Jeep MasterTech

    Satisfied Customers:

    576
    Factory trained and certified Jeep Master Technician, ASE Master Technician
  • http://ww2.justanswer.com/uploads/jeepmopar76/2009-3-18_2204_63998760.jpg jeepmopar76's Avatar

    jeepmopar76

    Jeep/Chrysler Triple Master Tech

    Satisfied Customers:

    572
    32yr ASE Master Tech, 9yr Chrysler Master Tech, 19 yr Jeep Dealership service including AMC/Eagle