No communication between obd2 scanner and vehicle

Does the check engine light work? It should come on with the ignition key in the on position. If not please check the system fuses 17, and 15. Also check the ALDL for corrosion and clean up the terminals as needed.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Here is a wiring diagram which pertains to most cars showing the power going to the ALDL connector.(below) If anyone reading this needs the wiring and the fuse ID to there car please send there request here.

https://www.2carpros.com/questions/new

Also, check to see if the scanner works on a different car.

We are here to help and tell a friend.

Best, Ken

No. The CEL does not come on at all, and the scanner will not read. I have traced most of the wires, and I did not notice any break. It was just something that happened, all of a sudden. I also checked the fuses.

Have you checked computer fuses and relays? If all are good it sounds like the computer could be bad. Test with the key in the "on" position.

Check out:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

and

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Please get back to me, I would like to resolve this issue with you. :-)



(Additional user comment) If scanner cannot connect and CEL does not come on, the problem is most likely the ignition switch.

I have checked all the fuses and they are all in good working order. The question is, which of the computers needs replacing? Thanks guys, you are great! Look forward to a donation because I may need you in the future.

Read the links, but I do not know if my car has any relay. I have never seen anything other than the regular fuses. Where will I find them?

Here is a diagram for your car on where the components are located. It sounds like it could be a computer problem by itself, but more testing is needed. Also, if the check engine light itself is out it will cause this problem.

I have ordered an adaptor for the data link connection. I will have to try reading it. What other testing were you recommending, and how do I make a donation on your site?

A physical inspection of the relay module did not reveal any damage or a breakage in the circuit board, and all the four fuses are in good condition. I did not remove the engine module.

If all electrical sources are good, the only test remaining is a pin to pin check with a wiring schematic while using a volt meter to check each wire. If all checks okay, the only thing left is the engine control unit itself, ECU. They do not go out very often, but it does happen. Please let me know what you find, I want to get this problem fixed for you. :-)

I will do that, and inform you of the results. If I may ask, what is the function of this part (210-545-0132 T/LLR idle control module)? I thought that might be one of the problems.

It is part of the ECU function which is integrated into the main computer ECU in later models.

Good day,

I have tried diagnosing the car with the round OBDII scanner, and I am receiving the same communication message. At this point, I am wondering what to do. I will also appreciate it if you are able to tell me which of the computer needs replacing, may be with the part number. Thanks for answering my question. I will post my experience(s) once I get it right.

Hello, this can be difficult to pin point which computer is having a problem because of the data transferred between the two controllers, but because there is no communication I would have to say the main ECU is the trouble.

Hi, I have a 1999 E320 Mercedes, 210 chassis. It has very high miles, 436,000, but a much newer engine, it is due for its yearly safety emissions inspection. The check engine light has been on for the last six months. All was well until recently it started having extended crank times, and then the last few days it's been stalling upon cold startup but it restarts right away. So I bought a Torque Pro plug in ELM 327 OBD2 scanner for my phone, but when I plug it in there is no communication. So I went to FLAP and they plugged in their scanner, and it says no communication, just like mine. So I looked at the plug in under the dash, and only four the many holes actually have contacts. But what could the problem be? The car is a two owner before me, and is really original and untouched, nothing has been hacked in any way.

Hello Corvairwild,

Do not worry about the connector not having that many pins in it most have pins missing which is normal. Try using the scan tool on other car first to see if it is working before checking the Mercedes. If it works check to see if the check engine lights works.

Please let us know what you find so it will help others.

Best, Ken

I tried my ELM327 Bluetooth, no connection, AutoZone tried theirs, same, friend tried his, same, a friend plugged in his Snap On Solis $4,000.00 scanner, brought up EGR code. I found a dried and split vacuum hose. I replaced it and another friend with a brand new $9,700.00 Snap On scanner was also able to read my codes. A new one appeared, intake air temperature, but that was probably a not well connected plug I had just removed and replaced. He turned off the lamp, and I have not had a chance to check the intake temperature plug, and it is raining now and I will be putting the car away for the winter in a couple of days.

I also removed the EGR Valve and it was minimally blocked with slimy residue, not a problem as it was ten percent blocked. The car occasionally stalls upon cold startup, and sometimes has extended crank time. I think that may be a weak fuel pump or bad crank sensor. Just a guess

Hey CORVAIRWILD,

Good find on that problem, on the older Mercedes it sounds like the more expensive scanner is the only thing that will work on some models.

Best, Ken

make sure scanner or app is compatible with Euro models. usually have to pay extra for the software for Euro models.

Great additional information to the thread.

Nice work

Best, Ken

My car stopped starting on me. I replaced the starter and the battery, but that did not fix the issues. When the ignition is turned, all it does is click, under the fuse relay box in the engine compartment, and the starter clicks. I checked all the fuses.

My neighbor hooked up his reader, but it would not communicate. Is it the computer in my car?

Th engine cranks, but it will not start. It is getting fire to the plugs. The fuel pump and filter are new new.
The fuel pump is not getting a ground when key is on. I wired it to the battery and it worked great. Still would not start. I can pour fuel into the intake and it runs. Getting fire to the injectors but no pulse. I had a scanner hooked up and it said no communication between it and the computer. All fuses are good. All electronics work. Just will not start. Also, it has the ring around the ignition. Not sure if that is the problem. Was told that does not shut off the fuel pump though. Any suggestions would be greatly appreciated.

It sounds like the relay module is no good please check the wiring diagram below and get back to me. also, check all system fuses.

Let me know what you find

Best, Ken

I work in the auto field and have access to more sophisticated equipment at work but needed to upgrade an older scan tool for home use. I decided to take a chance on this OBDII scanner tool. Still early for me but I have been impressed with the tool so far and would recommend to anyone with average to intermediate repair skills. For the money this tool is hard to beat.

Great addition to this thread! Please feel free to help out whenever you are on the site :)

Cheers, Ken

So i have a question guys my buddy plugged in his 4k scanner onto my g35 coupe it does have a swapped motor. And nothing showed it was blank my uncle has the same car he plugged it on his and it read everything fine -.... Could i be having a possible ecu issue ? Car isnt throwing any codes engine light does illuminate when on accesory and car will start but wont stay on

Yep I can help but this thread is for a Mercedes. Please post your new question here, you must be logged in.

https://www.2carpros.com/questions/new

Cheers, Ken