PO disabled the MIL system. How?

[Zaniei3]

Long story short, previous owner had disabled the check engine light because of several fault codes. I have fixed every one of them and even replaced the bulb for engine check light but I am still getting MIL is on and I can not inspect the car! I think he has cut a line somewhere to this bulb on the dash! I can not even find it in the wiring diagram. Any help is great appreciated

2002 z3 3.0i

 

[ChrisD]

Start the engine, the MIL will not be on without a fault code present. You'll need an OBDII scanner to find out what might be keeping the MIL on.

 

[Zaniei3]

Start the engine, the MIL will not be on without a fault code present. You'll need an OBDII scanner to find out what might be keeping the MIL on.

With the scanner it shows no faults but since it has been tampered with it shows MIL on

 

[Zaniei3]

I know for a fact he has tampered with the wiring. The bulb was missing but even after placing a new bulb it didn’t light up. So a wire has been cut somewhere.

 

[ChrisD]

I’d look at the most accessible points first. Maybe start with the ECU connector and check no pins backed out of the connector.

 

[Kenhayes247]

Just to be clear, with the key in the ignition and turned to position 2 the MIL is on. When you start the car, the MIL remains on even though there are no faults or it goes off?

 

[ChrisD]

I’d look at the most accessible points first. Maybe start with the ECU connector and check no pins backed out of the connector.

BUT… if there is a problem with the MIL circuit, it should be setting DTC P0650.
The MIL should show as off if the engine is running and there are no DTCs. If not, the ECU may be damaged.

 

[Kenhayes247]

If the light is not on, irrespective of the key position, I would check again the bulb you put in but preferably use a voltmeter to check the connections. Key in ignition and turned to position 2 so there is voltage present

 

[Zaniei3]

Just opened it up and noticed the new bulb was in the wrong hole. I ordered new bulbs and will report back with results. Fingers crossed!! Thanks again for all your help.

 

[Kenhayes247]

Fingers crossed indeed, check the new bulb for continuity before fitting or onnect it to a power source to make sure all is okay, good luck.

 

[ChrisD]

Another thought:
Engine = run, DTC count = 0, MIL = ON is an invalid condition.
if you are seeing this then something is very, very wrong or else you shouldn’t trust what your scan tool is telling you. In this circumstance I’d try a different tool. An OBDII generic scanner would be my choice vs something that claims to be ‘BMW specific’ or somesuch as that may mask off some real DTCs.

 

[ChrisD]

Also, if you have fixed all of the faults, you still need to clear codes. Although there may be no current codes, there will be historic codes and these need to be cleared to extinguish the MIL. Apologies if this is obvious, it’s difficult gauge the level of help that’s needed. Particularly as we are discussing two separate issues: MIL indicating on with no faults and MIL not illuminating.

 

[Zaniei3]

Update: I did have the bulb in the wrong location. MIL is now illuminating and there is absolutely no fault codes. I have cleared the code and still MIL is on. I have now disconnected the battery to see if it would reset. More to come and thanks for all the help.

 

[Zaniei3]

Reconnected. Reset the codes and still MIL is on. The only item in diagnostic showing is in the pic

 

[ChrisD]

Ahh... I see the problem. An old-school OBDII tool with non-intuitive data display and a mess of hex, decimal and various OBD modes, TIDs, etc. Unfortunately I cannot direct you to the correct area to look at as I am unfamiliar with this particular tool. I'd strongly recommend upgrading to a 21st century OBDII scanner.
I use a wireless interface plugged into the OBD port (can be obtained for ~$10) and a free app that can translate OBDII data into easily interpreted information. This should help eliminate the current situation where the data presented is inconsistent with the system it is interrogating.

 

[Zaniei3]

Ahh... I see the problem. An old-school OBDII tool with non-intuitive data display and a mess of hex, decimal and various OBD modes, TIDs, etc. Unfortunately I cannot direct you to the correct area to look at as I am unfamiliar with this particular tool. I'd strongly recommend upgrading to a 21st century OBDII scanner.
I use a wireless interface plugged into the OBD port (can be obtained for ~$10) and a free app that can translate OBDII data into easily interpreted information. This should help eliminate the current situation where the data presented is inconsistent with the system it is interrogating.

I use exact the same one as well. Bluetooth into the port and read it with my iPad. I will take it to get it inspected tomorrow to see if they can tell me what is wrong. Thanks for your reply.

 

[ChrisD]

If you have the hardware already you could try this app:
https://www.carscanner.info/ (free version can read codes)
It may help to provide better info.

 

[Zaniei3]

Update: this morning started the car and check engine light was off. So I ran to get it inspected but it failed because of following reasons:
O2 sensor: not ready
Catalyst: not ready

the guy said I need to drive it around for 50 so miles below 60mph until these tests are ready.
Thoughts???

 

[t-tony]

I wouldn't have thought you would have to do that amount of miles to get the engine warm enough for it to pass an emissions test.
I suspect that the oxygen sensor is failing.

Tony.

 

[ChrisD]

Update: this morning started the car and check engine light was off. So I ran to get it inspected but it failed because of following reasons:
O2 sensor: not ready
Catalyst: not ready

the guy said I need to drive it around for 50 so miles below 60mph until these tests are ready.
Thoughts???

Yes, those non-continuous OBD monitors need to run in order to pass the test. If you are driving in the right conditions then a couple of miles should do it. BUT you have to be driving in the right conditions. The monitors typically run in the 30 - 50 mph window, light throttle, plenty of overruns. You’d be very unlucky not to hit the right conditions within 50 miles but it is possible, especially if you have a heavy right foot. Do the 50 miles, as instructed, and you should be fine. If not, expect an eye-roll from the test guy and an ‘out you go again, sir’ instruction. It seems as though your issues are 99% resolved - well done.