Member
Ok I'm trying to help get a friends car back on the road, a 2001 330ci. He was driving and serpentine belt broke so he pulled over and had car towed to his house and then to mine. Fixing the belt wasn't really a problem as that is pretty straight forward but after he got the car home it would not crank.
Battery is 2 months old and tests good and holds a charge of 12.8 volts. I swapped in another battery just to be sure and still no crank. I then started suspecting ews failure and started testing fuses and harness. Was able to get the car to crank by jumpering the two wires in slots 1 and 2 which go from ignition switch in and out to starter. After verifying that pins 9,10, 12 had proper voltages I decided to test to see if pin 6 was getting a signal in P and N which it did. I then jumpered the 1 and 2 pins with a paper clip from wire side of harness with ews module plugged in and car started right up. This would indicate that something is not allowing the ews relay to send power to starter.
I drove the car to see what was going on with the transmission indicator and car would not shift out of 1st gear. My foxwell 520 scan tool shows no faults in transmission computer but had a 0f code for ews and DME had transmission code which I forgot to write down. Suspecting that maybe the trans neutral safety switch on the side of the zf transmission was faulty I tested the pins for continuity for each position the gear lever was in. It tested flawlessly so I have to rule that out. Connector pins looked nice too, no corrosion inside.
I scanned the TCM for live data and it showed null for gear indicator and nothing when position was changed. It did respond when in D and lever moved left to S with the S displayed in the cluster and the up and down manual shifting switches showed working on the scanner. It also said car was in 4th gear but when I drove it it was definitely in 1st. Also checked the 5 fuses in DME compartment. All tested good and was getting voltage on 2,3,4 with ignition on but not on 1,5.
The fact that the car runs with the wires in the ews harness jumpered tells me the DME is fine. I am suspecting the TCM is bad now. I can pull one from an 03 525i from another buddy and throw it in to see what happens but I have no idea if that really is the problem. What tells the display in the cluster what gear your in? The TCM or the switch on the side of the tranny or both? Could the safety switch be bad even though it tested properly? What should I test next? Could the ews starter relay be bad? Please point me the right direction. Thanks for any and all help!
Member
Swapped in another transmission control unit module and still no gear indicator in the cluster.
Member
Checked all DME fuses and found fuse 30 was blown. Replaced and problem is all fixed. Gear indicator in cluster works again and car starts up just fine. That was a lot of testing to end up being a fuse. It wasn't like I hadn't looked for a blown fuse either, just not for the DME!
Member
Excellent work, Wodctr. I was thinking that one of the harness connectors got whacked when the belt let go. Just bad luck the fuse went out at the same time.
Johnny Murray
Member
Another update! Buddy wanted oil pan gasket leak fixed as long as I'm in there. When I pulled the oil level sensor connector I saw where 2 of the 3 wires going to the sensor were frayed and completely separated up behind a bracket on the motor where they had obviously been rubbing against. Fuse 30 also protects this circuit which definitely explains the blown fuse. The wires are in a place where there is no way a broken belt could have caused the damage, so who knows why the fuse decided to blow at that time...coincidence or BMW Covid19 Gremlins?
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