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 sprinkles08 Your Own Question

sprinkles08
sprinkles08, ASE Certified Technician
Category: Car
Satisfied Customers: 16447
Experience:  ASE Master and Advanced level certified. Factory trained with 14 years dealership experience
Type Your Car Question Here...
sprinkles08 is online now
A new question is answered every 9 seconds

Mazda 6: 2005 mazda 6 blows "Eng+B" fuse and wont star

Customer Question

2005 mazda 6 blows "Eng+B" fuse and won't start. Acts like it does not recognize the chip in the key. Just replaced alternator and battery. FYI After replacing battery I checked to see if the alternator was good by doing the old shcool trick of taking the battery cable off while running. I have learned that was the wrong thing to do. I blew out a few fuses and low beam headlights. but now I have this 7.5 amp Eng+B fuse that blows like a dead short any time I connect the battery and the car wont start. Any ideas
Submitted: 10 months ago.
Category: Car
Expert:  sprinkles08 replied 10 months ago.

Hello and welcome to JustAnswer!

 

Most likely the problem is internal in the engine controller (ECM) as a result of removing the battery cable. This will cause charging voltage to suddenly spike very high. Try disconnecting the ECM and putting a fresh fuse in and see if it still blows. If not then the problem. is internal in the ECM.

Customer: replied 10 months ago.


Yes, I disconected the ECM and the fuse did not blow. When I replace it will I have to have the keys reprogramed or will the keys still start the car? Is there any way to avoid the tow to the dealership and paying for the Keys to be recoded to the new ECU?

Expert:  sprinkles08 replied 10 months ago.
If you have programmed transponder keys Then it does take programming once installed. An alternative to towing would be if someone could bring a dealer level scan tool to the vehicle and do the programming wherever it is. You may be able to find a dealer, shop, or individual that will come to you.
sprinkles08, ASE Certified Technician
Category: Car
Satisfied Customers: 16447
Experience: ASE Master and Advanced level certified. Factory trained with 14 years dealership experience
sprinkles08 and 17 other Car Specialists are ready to help you
Customer: replied 10 months ago.

Well after spending $400 on having the ECM rebuilt I have the same problem. The 7.5 amp Eng+B fuse blows any time the battery is connected. It is a dead short. I can't find what the Eng+B fuse runs. The ECM is in the circuit, but there has to be an element that has gone bad and caused a dead short.


Problem started when I removed the battery cable with the car running.


Other symptoms: Car won't start. It will not send power to the starter. Do you have any idea what is on the Eng+B circuit? This fuse is in the main fuse box in the engine compartment.

Expert:  sprinkles08 replied 10 months ago.

The fuse doesn't blow with the ECM unplugged, correct?

 

It was sent to an aftermarket repair facility and they returned the same one to you?

Customer: replied 10 months ago.

Yes, They had to rebuild the ECM. I sent it to GO-ECM in Texas. Yes, the fuse does not blow if the ECM is unplugged.

Expert:  sprinkles08 replied 10 months ago.
Do you have a voltmeter or test light?
Customer: replied 10 months ago.

 


yes I have voltmeter and test light. I have a Chilton Mazda 6 manual but the wiring diagram does not show the 7.5 amp circuit. If you have a suggestion please assume that if I don't have it I will be able to go and get it. I did pick up a code reader to see if I could get some direction but with the 7.5 amp Eng+B fuse blown I am not able to communicate with the car.

Expert:  sprinkles08 replied 10 months ago.

What I want to do is unplug the ECM and then check for a short to ground on each wire. If there is a short on some circuits it could possibly blow the fuse.

 

Set up your meter with the black lead ground and the meter set to the 200 ohm scale and then use the red lead to probe each wire at the ECM with the connector unplugged. If you see any wires with continuity to ground note the reading and the wire color. Let me know your results and then I'll go through the wiring diagram and see if the results are normal or not.

 

 

Customer: replied 10 months ago.

Is there any way I can get that wiring diagram? I have chilton's-no help.


The Ecm itself has one pin that is conected to its body ground. The wire harness does not have a wire in that location.


here are the pin location #--ohms and color of direct short wires.


#6,#9, #22, #23, #25 and #100 are black/blue+silver dots and 0.0 ohms.


#32—0.0 red


#36--0.3 green


#47—0.0 black/yellow


#48—0.0 green


#56--0.0 green/red


#68—0.0 green/white


#73—0.0 yellow


#74—0.0 blue/red


#82--0.0 green/yellow


#94—0.1 pink


#97—0.0 brown/yellow


#98—0.0 red/green


#99—0.0 pink


#100—0.0 black/blue+silver


There are 10 wires with 2.2 ohms I will list them if needed. These were not direct to ground.


Thank you so much for your assistance.


 

Expert:  sprinkles08 replied 10 months ago.

Great, thanks.

 

I'm away from my service information right now, I'll over these and get back to you as quickly as I can this evening!

 

You have three connectors at the controller, correct?


Customer: replied 10 months ago.

You asked me "You have three connectors at the controller, correct?"


No the ECM has one large connection that has a 10 mm bolt holding it in place. It has 104 pins in that wire plug.


this is a 2005 Mazda 6i with a 2.3 4 cyl engine, automatic that as it turns out is a california model according to Go-ECM. I have not been able to come up with a good wiring diagram to help me out. I am most concerned about what those red and pink wires might be going to, since those probable should not be direct connection to ground.

Expert:  sprinkles08 replied 10 months ago.

The California emissions could be the difference. I'll double check this evening and see. The standard emissions package vehicle's ECM uses three separate connectors which is why I asked.

 

 

Customer: replied 10 months ago.

I was able to get a copy of the Mazda shop manual that helped me quite a bit. The PCM or ECM diagram shows pin locations #6,9,22,23,25, and 100 are straight to ground and they test out at 0.9 or 1.0 ohms. Pin location 56 and 82 are respectively 1.1 and 1.5 ohms. I isolated those wires and reconnected the harness and I still blow the 7.5 amp Eng+B fuse. Five other pin locations have 69.8 to 73.5 ohms. An A/C relay has 187.3, and a Evap System Pump has 148.3. I am sending the ECM back to Go-ECM. (Mazda calls it a PCM) You have helped me with your suggestions. Am I wrong to ignore the readings that don't show a dead short to ground?

Expert:  sprinkles08 replied 10 months ago.
The ones with the high resistance to ground shouldn't be a factor. I expected that the company had missed something when they had it because disconnecting the battery like you did really shouldn't have caused a short to ground on any circuits. I wanted to be sure though before having you send it back to them.

If you didn't already, I would make sure they knew what happened and what fuse is blowing now and that will help them find the internal failure when they get it back.

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
  • Excellent reply, and also very quick. Really sounds like the Expert knows what he is talking about. I will be back to use your service when I need more help with my RV. Dutch USA
 
 
 

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