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Chris (aka- Moose)
Chris (aka- Moose), Technician
Category: Mazda
Satisfied Customers: 47711
Experience:  16 years of experience
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1998 mazda b2500 OBDII not communicating with emissions test

Customer Question

1998 mazda b2500 OBDII not communicating with emissions test machine.
Submitted: 1 year ago.
Category: Mazda
Expert:  Juan Crespo replied 1 year ago.

Hi there.

When you say "emissions test machine", are you referring to a generic scan tool? If so, have you tried a different one? reason for asking is that some generic scanners and code readers will not communicate with Mazda vehicles.

Also, what are you trying to diagnose/fix?

Customer: replied 1 year ago.
The emissions test machine is for the vehicle state emissions test required in Texas. I do not have a scan tool. Every time I think I may have found the problem I have to take the vehicle to be re-inspected. The fault on the computer says OBDII connection time out. All I need to do is pass the emissions test, but I cant run the test until there is proper communication. I have also taken it to two different inspection places to rule out the machine.
Expert:  Juan Crespo replied 1 year ago.

I see. There is an easy way to determine whether the fault lies with your vehicle or their emissions test machine; go to any major auto parts retailer such as Advance Auto, Autozone, O'Reillys, etc. and ask them for a free computer scan. If their scan tool communicates with your truck, then go back to the testing facility and tell them what has happened and ask them what is the official procedure to follow in cases such as yours.

However, if the auto parts' scan tool cannot communicate either, then the issue is with your truck - we can help you with that as well if necessary.

Customer: replied 1 year ago.
I did exactly that when I replaced the ecm. They were unable to get any codes from my truck although they couldn't tell me if it was because it was communicating or not. The inspection place has done several inspections after me so I doubt it's a problem with their equipment.
Expert:  Juan Crespo replied 1 year ago.

I'm not saying the emissions test machine is bad, just saying it might not be working on your truck.

I don't quite understand the rest of your post; have you gone to an auto parts and ask them to plug in their scan tool and see if it communicates with your truck - not if there are codes stored?

Customer: replied 1 year ago.
They said the tool ran a code search but they don't know if it's the same way the emissions test communicates with the ecm.
Expert:  Juan Crespo replied 1 year ago.

If they said that their scan tool did run a code search, then why don't you go back to the test station and ask them about any special dispensations for cases such as yours?

Customer: replied 1 year ago.
I wouldn't be asking you if I haven't exhausted absolutely every person I could possibly talk to. I have been to the parts store at least 5 times, replaced the entire computer, ive been to the inspectors 4 times at two different locations and nobody can think about what could be causing this issue... do you have access to the schematics to the DLC port and what is tied into the system? ??
Expert:  Juan Crespo replied 1 year ago.

Now I'm confused... I thought the issue was the testing station couldn't communicate with your truck's PCM, but the auto parts could. If that's the case, nothing you can do can fix the situation.

Now, if you're saying there is an issue with your truck that is impeding communications with a scan tool, then I could potentially help you with that - only problem would be you not having a scan tool to use during our diagnostic process. Can you borrow one? Also, does the check engine light come on when the ignition is switched on?

Expert:  Juan Crespo replied 1 year ago.

I'm sorry, but at this point there's nothing I could contribute that would help you solve your issue. I'll opt out so others may try. Please don't reply until another expert responds or the site will cycle this request back to me.

Expert:  Chris (aka- Moose) replied 1 year ago.

Welcome, I'm Chris (aka Moose).

The prior tech has opted out.

If I understand no scan tool tool will link to your vehicle for scanning and monitoring, correct?

Customer: replied 1 year ago.
Correct. I don't have a scan tool myself but I can test each pin and give you readouts to help.
Customer: replied 1 year ago.
The issue is getting a state emissions test. The results just say OBDII failed. Timed out.
Expert:  Chris (aka- Moose) replied 1 year ago.

Okay lets start with the wire diagram below.

At the DLC you should get power on orange wire and ground on the black and black white wire. These 2 will power up the scan tool.

Next unplug the PCM and OHM test from the PCM to the DLC the purple, pink/light blue, and tan orange wires. Ohm test them from both ends to make sure they are not broken. Then Ohm test each wire to battery positive and negative to verify there is no continuity from wire shorts. If all tests pass then communication should be able to occur.

Please make sure to select a rating from the top of your screen prior to logging off so the post does not time out.

Thanks Moose.

Customer: replied 1 year ago.
Ok, I'll try this out and let you know the results in a little bit.
Expert:  Chris (aka- Moose) replied 1 year ago.


Customer: replied 1 year ago.
OK, all checked out... All three (purple, pink/, tan/orange) had an ohm reading end to end .4-.5. each wire when tested against positive and negative leads had no reading (pcm still disconnected). This is the reason I have been pulling my hair out on this one. after 4 retests I don't know what else to try...
Expert:  Chris (aka- Moose) replied 1 year ago.

According to your tests the only reasons left could be the PCM and the ool being used but you said you replaced the PCM and the emissions place and a parts store could not communicate. Do you know someone with a dealer equivalent tool that can do a data link diagnostics test?

Customer: replied 1 year ago.
Unfortunately I don't have access to any sort of tool like this. I called an auto shop ando they wanted 100.00 just to hook it up.
Customer: replied 1 year ago.
Good news! I was able to rent a scan tool from autozone. I have no clue how to use it but I'll see what I can do to figure it out.
Customer: replied 1 year ago.
I don't know exactly how everything works on here but I think its all working properly?? I was able to watch live feed and there were values for all of the sensors. I found an OBD monitor test that had a multitude of options so I ran them all. Most came back with an OK status so I didn't note those, but the ones that came back high I took a picture of so that I could tell you which test it was (if it even matters).
test ID $10 (1/2) test value $FFFF status high
test ID $53 (5/10) value $10DF status high
test ID $53 (6/10) value $00FF status high
test ID $53 (7/10) value $885F status high
test ID $53 (8/10) component ID $08 value $08BF status high
test ID $53 (9/10) component ID $09 value $69FF status high
test ID $53 (10/10) component ID $0A test value $69FF status high
test ID $56 component ID $00 value $1EE8 value highI tried to run a code test but the battery had been unplugged all night, here's what it said .. No powertrain DTCs or freeze frame data is presently stored in the vehicles computer.
Customer: replied 1 year ago.
I have been driving it around to get enough mileage to have all of the sensors respond. But right now I don't have a green light on the o2, had o2, cat and eva.
Expert:  Chris (aka- Moose) replied 1 year ago.

It takes about 2 weeks for the monitors to all complete. Those test ID#s do not cross reference to Ford info. The parts store most likely has a manual or website login for this tool which tells them what those numbers mean.

The point though is you can communicate with the computer so the concern is the testing center, not your vehicle.

Customer: replied 1 year ago.
I really wish it were the testing center, but I have taken the vehicle to another city to have it tested and it's still the same problem. I am so lost on what to do. It seems as if it's communicating but it's not when I need it to. Maybe I can run the codes as a Ford ranger? It's basically the same vehicle.
Customer: replied 1 year ago.
ok under a ranger here are the results
catalyst 2 sensor 1 high
egr sensor voltage amplitude-bank 1 sensor 1 low
misfire high 7/10
misfire high 9/10
misfire high 10/10
I have read that voltage spikes and irregularities can cause problems with tools being able to communicate through the OBDII connection. Could any of this be an issue?
Expert:  Chris (aka- Moose) replied 1 year ago.

A trouble code looks like P0301 misfire cylinder #1. The info this generic tool is giving us is not that helpful.

Customer: replied 1 year ago.
Sorry, I'm giving you what I can. I have never used this kind of tool before. I'm going to take it up to another shop to see if there is communication. If not I'm right back in the same boat...
Expert:  Chris (aka- Moose) replied 1 year ago.

Keep in touch if needed

Expert:  Chris (aka- Moose) replied 1 year ago.

Hello again Chris here,

I am contacting you because the post has not been closed or rated. We have 7 days to get a post rated before it times out. When a post times out, that means its no longer on my active list (if you reply I never know it.) You have already paid the fees to get this question answered, but it appears your not pleased, or need more help.

Let me help some more. Is there anything else you feel I could offer so you would be pleased with my help. I have the option to call you if that would be better.

Thanks Chris

Customer: replied 1 year ago.
Sorry, I've been working graveyards and not been able to get the truck tested yet. I'll be going to another inspection place in the next few days. I'll let you know the results.
Expert:  Chris (aka- Moose) replied 1 year ago.

Thanks for keeping in touch. Please continue prior to the post timing out and closing on the 22nd