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I have a 1996 328IC and have two different codes being thrown: The First is (both AfterCat Oxygen Sensor Heaters showing a fault). The second is that the CEL (Check Engine Light) is out. I have replaced all 4 O2 sensors and the relay for the Oxygen sensor in the fuse box under the hood, and checked the bulb in the cluster. All seem to be working. What do I do to check for a snipped wire on the CEL?

Submitted: 479 days and 3 hours ago.

Category: BMW

Value: $40

Status: AWAITING CUSTOMER ACTION

Optional Information:
1996 BMW 328ic 6cycl (m52?)

Already Tried:
I have changed out all 4 O2 sensors, Checked the bulb for the CEL and replaced it. I just cannot figure out why the CEL will not come on when I have codes that I am reading on my code reader (AfterCat O2 Sensor heater on both of them) What should I try next?

Accepted Answer

Are you able to clear the codes? Have you checked your spark plugs lately? How many miles on the car? Even though you get an o2 sensor code that does not mean it is defective. When was your last tune up? let me know Thanks.

Accepts:
Expert:	Wesley
Pos. Feedback:	97.8 %
Answered:	7/31/2008

BMW Technician

Servicing and Repairing BMW's exclusively for 20 years. Previous owner of Independent repair shops.

479 days and 1 hours ago.

Reply

I have put new: Tires, spark plugs Radiator/WaterPump/Hoses/Thermostat, and new radio on.

When I first saw the car (bought it 5 months ago)it had a CEL and the seller told me that it might have an O2 sensor out. As part of the sale I got him to "Fix" the light at his mech (I got a receipt for the work and the CEL was out, I was soo trusting). (I didn't realise that the CEL wasn't lighting up at all as part of the normal engine start up)

I had just gotten back from the sandbox (Baghdad) and MD sent me a notice for an Emissions Test. I thought this would be a $15 quickie and I would be on my way, well I failed. There were several codes detected (Check Engine Light, 3 of the 4 O2 sensors were OOC, AfterCat O2 Sensor Heater(?) for both AfterCat Sensors, and Secondary AirPump Pressure Low).

I have replaced all four O2 Sensors, the Oxygen Sensor Relay in the fusebox, and the CEL bulb in the instrument cluster. (I disconnected the battery while I changed the bulb hoping that this would clear the computer). I was extremely careful about any possibility of crossing wires. I don't think that any of the sensors were changed out by the seller, at least judging by the sooty appearance of the sensors when I took them out.

I am still without a CEL (can't figure out that one), and am throwing the codes for the AfterCat Oxygen Sensor Heaters.

Andy

479 days and 1 hours ago.

Reply

I went back out and reconnected the battery. It had been disconnected since last night. I ran through the code reading proceedure and then re-ran the clear codes routine. It worked on all but the Check Engine Light (which is now the only code I get)
Andy

Posted by Wesley 478 days and 21 hours ago.

Answer

It may be that the tech that worked on the car before you may have done something with the cel since you said it was on when you first saw the car. Is it possible to ask him if he disconnected something to make it stay out. This could save an awful lot of time. If not then the only thing to do is have a tech trace the cel wires to see where the interrupt is. Let me know.

477 days and 2 hours ago.

Reply

I don't see any answers, maybe the question was unrealistic.

Posted by Wesley 477 days and 1 hours ago.

Answer

You wanted to clear your codes? You don't have a check engine light on now but when you first saw the car it was on? The guy you bought the car from had someone make the check engine light go out? I was asking if there was a chance if the person who worked on the car may have done something with the light? Let me know if that is a possibility. Thanks.

475 days and 4 hours ago.

Reply

Thanks,

I can't say for sure at this time about what was done before. I just know that before I buy any used car again I will buy/rent borrow a code reader to put to the car before I buy.

I guess the question I asked was unrealistic,
I will not be using this service again.

Posted by Wesley 474 days and 23 hours ago.

Answer

I am sorry to hear that. I am sure your very frustrated about the car. I know it can be very difficult to trace a problem that someone else may have caused. In order to trace your check engine light wiring you must have a brake out box that will check all of the wires in the control unit. I was hoping to bi pass that since you had a check engine light on before it was worked on by another tech. Good luck with your car.

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Accepted Answer

Are you able to clear the codes? Have you checked your spark plugs lately? How many miles on the car? Even though you get an o2 sensor code that does not mean it is defective. When was your last tune up? let me know Thanks.

Reply

Reply

I went back out and reconnected the battery. It had been disconnected since last night. I ran through the code reading proceedure and then re-ran the clear codes routine. It worked on all but the Check Engine Light (which is now the only code I get) Andy

Answer

Reply

I don't see any answers, maybe the question was unrealistic.

Answer

Reply

Thanks, I can't say for sure at this time about what was done before. I just know that before I buy any used car again I will buy/rent borrow a code reader to put to the car before I buy. I guess the question I asked was unrealistic, I will not be using this service again.

Answer

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I went back out and reconnected the battery. It had been disconnected since last night. I ran through the code reading proceedure and then re-ran the clear codes routine. It worked on all but the Check Engine Light (which is now the only code I get)
Andy

Thanks,

I can't say for sure at this time about what was done before. I just know that before I buy any used car again I will buy/rent borrow a code reader to put to the car before I buy.

I guess the question I asked was unrealistic,
I will not be using this service again.