BMW Fault Code: 4691 Supply Voltage 3


I need help to troubleshoot my BMW X3 car  BMW X3 E83 LCI 2.0L  Diesel year 2007  chassis number WBAPD11060WF91665 The BMW fault code is : 4691 (supply power voltage3)  the ECU was removed and sent to ECU testing in UK and it was found OK. I also need the wiring diagram including the ECU diagram if you can assist.

BMW Fault Code: 4691

4691 – DDE: Supply voltage 3, engine management

I can appreciate the issue you are having. The information that is available to me is US Domestic only. I do not have Resources for UK Vehicles. 

I did spend a couple of hours scouring the internet in the hopes of obtaining some helpful reference. From what I understand this is in most cases an internal ECU issue but not limited to it. Since you have had yours tested, other than trying it in a different car to prove it is GOOD or a known GOOD ECU out of another working vehicle we are reliant upon the testing facilities response. So we will assume it is a good ECU. 

In that case the Crank sensor is a possibility along with poor wiring connections both positive and negative. Or damaged wiring harness connecting the ECU. This also includes confirming the ECU Fuse is also GOOD. 

I read some reports of some finding melted wires near the exhaust pipe that caused the ECU to throw code 4691.

Another similar case found that at some point an electrician or someone had repaired the wiring(vehicle had been in an accident) and the sleaving on some of the wiring was exposed. And some the thinner wires were touching the big red/*********** wires. 

I know it might be easier to understand looking at a wiring diagram but for now I do not have access to UK Specific information. 

Thank you for the donation and for visiting

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