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Category: BMW
Satisfied Customers: 3498
Experience:  Manager/co-owner at Autotronic
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1987 BMW 325 Just failed smog test due to my check engine

Customer Question

1987 BMW 325 Just failed smog test due to my check engine light not coming on when the key is in the #2 position. I need someone to assist me in resolving this issue.
Submitted: 1 year ago.
Category: BMW
Expert:  nabilc replied 1 year ago.
Hello and Welcome! I'm Billy and i will assist you with your inquiry. Feel free to ask if any further info is needed.
Did you remove the instrument cluster to check if the "CHECK" light bulb is good? you can swap with any other one at the back of the panel for checking...
Customer: replied 1 year ago.
Hey Billy, thanks for taking my question. Yes, I did remove the cluster. I found that the check engine light bulb socket had been pulled and there was no bulb in the socket. I used the bulb from the ABS socket and it did not work. I then tested the socket and found no power at the socket. I then clipped my ground directly to a ground on the car and touched the green wire on the socket and found that the green wire was hot when the key was in the #2 position and it did not go out after starting the vehicle.So it appears that the check engine light is staying on after the car is started. However the brown ground feeding the check engine light socket is not grounding? Not sure what I should do next?
Expert:  nabilc replied 1 year ago.
Wouldn't you be able to connect the brown wire to any ground location near, so the light is on....
And then you check what's wrong (what's keeping the green supplied) as the check engine light should get the green from the pin 15 at the engine control module. If this one is good continuity, then just give the brown ground and we're good to go on the check engine light.
We would still figure out which errors are stored keeping the light on.
Customer: replied 1 year ago.
Yes, I agree on the ground anywhere thing, although I'm a bit troubled as to why there is no ground? I can live with it if the solution would get too involved and a bit unnecessary! So how do we figure out what's causing the check engine light to stay on?
Customer: replied 1 year ago.
BTW Billy, again I appreciate your taking my question and I'm happy to give a bonus for your helping me solve this problem! I'm not sure how much time I'll be able to work on the car today? I'm scheduled to work on Motorcycles for the better part of the day today. Hoping you wont mind giving me some direction that I can later follow as we go along.
Expert:  nabilc replied 1 year ago.
Given the age of the vehicle, i would not be troubled as to why a certain wire got disconnected.
First let's check the continuity to the ECM pin number 15, as this might be for the ground, (and not the positive as indicated earlier) so we have this fixed...
If there is no continuity for the green wire, then connect the brown wire to pin 15.
As for the fault codes:
To read codes for an OBD I car, you start by turning the ignition key on (do not start the engine) and pressing the gas pedal to the floor five times within a period of five seconds. If you proceeded correctly, then the check engine lamp will light on for five seconds, then blink off, then blink on for 2.5 seconds, and then go off for another 2.5 seconds. After this, the computer will start to show you the trouble fault codes that are stored.
I will attach the details (but you don't need the breakout box once you have the check engine light working, as you will see the flashing on it):
Thank you for your trust! Get back to me if you need more assistance...Thank you in advance for the positive rating...
PS: you're most welcome, take your time, and get back to me on this page when needed.
Customer: replied 1 year ago.
Awesome, will do, thanks Billy!
Expert:  nabilc replied 1 year ago.
Customer: replied 1 year ago.
Hey Billy, Sorry it's taken so long to get back to you. Unfortunately I have not been able to get back to this particular issue. The car belongs to my 23 year old son who's been using the car for work and activities and we've just not been able to connect to resolve the issue. I ended up cheating the check engine light in order to pass smog. I barrowed the ABS socket in the back of the cluster and stuck it in the check engine hole. This allowed the light to come on when key was in #2 position and off when started. So I still need to get to the bottom of why the check engine light is on in the first place. Would you like me to give you your excellent rating now, or are you ok with waiting to see if there are any follow up questions. I should be able to hopefully get it done this week! I really appreciate dealing with someone that knows what they're doing! Thanks again,***** *****
Expert:  nabilc replied 1 year ago.
Hello Aaron,
Take your time, and get back to me with the results...