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 Chad Farhat Your Own Question
Chad Farhat
Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems
Category: BMW
Satisfied Customers: 3427
Experience:  Owner at Carolina Auto Service & Sales , 20 years Experience in Foreign & Domestic vehicles
Type Your BMW Question Here...
Chad Farhat is online now
A new question is answered every 9 seconds

A friend has a 2000 bmw 740i. i worked in a transmission

Customer Question

a friend has a 2000 bmw 740i. i worked in a transmission shop many years. i tooking his trans out and sealed the front. i had the battery disconnected about 12 days. the battery is weak. had to jump it off. trans worked fine but the speedometer did not. soon it started in higher gear. snapon scanner said it was a speed senser. i replaced both. did not help. also tack does not work and the gauges do crazy things. does the ecm need resetting? i have run into a bad ecm ground on other cars. maybe that is the problem. i dont know. can you help me?
JA: How old is the battery? And have you tested it with a voltmeter?
Customer: i do not know how old the battery is. he just bought it. i have not tested it but you have to jump it or put a charger on it if it sits a few days
JA: Are you fixing your 740i yourself? What have you tried so far?
Customer: it is my friends. it might as well be mine. yes i am fixing it. the only thing i have done is seal the trans and put both speed sensors on it.
JA: Anything else you want the mechanic to know before I connect you?
Customer: i cant think of anything
Submitted: 8 months ago.
Category: BMW
Expert:  Chad Farhat replied 8 months ago.

Hi, I'm Chad. Welcome to JustAnswer. I'm reviewing your question and I will be posting your reply ASAP.

Expert:  Chad Farhat replied 8 months ago.

hey man how are you

1- we have to start with testing battery for 12 volts & under load do you have 12 volts

2- with car running at the battery with voltmeter , do you have 14 + volts with headlights, ac , radio on etc..

3- after you replaced the VSS sensors did the fault clear with your scanner, can you pull up the sensors and go down the road and see if they are reading

or is it not moving or going in gear ?

4- as far as bad ground and bad ecm , yes that is possible, but we have to start with a good 12volts & alternator charging for theses cars all of modules involved and if not enough power generated they will shut down or you want be able to clear the faults .

Please let me know

Thank You

Chad Farhat

ASE Certified Technician

Expert:  Chad Farhat replied 8 months ago.

Please let me know if you need anything else on it, just reply back and we will continue

If you are good, Please Kindly Rate Me.

A 5 Star Rating is much Appreciated

If you feel I have not been helpful Please DO NOT RATE ME BAD OR POOR (1 or 2 stars) ,You can always ask me again or I can opt out of your question & open it for another expert ,that will provide you with more or better assistance on this issue

Please keep in mind that when you rate me , it does not end our conversation.

you can always come back to this conversation and ask me any follow up question you may have on this issue

(you can copy this link page & paste it in your browser when ready and it will open up our conversation again)

Thank You
Chad Farhat
ASE Certified Technician

Related BMW Questions