2005 Z4 - What am I looking at?

[billsz4]

Uh oh!

Pulled the car cover off of my wife’s 2005 3.0 and found the 1 year old battery dead. Replaced the battery and started her up, only to find a number of dash lights (I assumed these were related to the low voltage/dead battery). ABS, Brake, DCS. Popped the hood and found, well, a huge pile of leaves (something clearly was very comfortable in there). After cleaning it out, noticed a multi plug with several wires chewed through!

Where do I go from here? Do I need a new harness? Other ideas/solutions?

[Sterling Roadster]

While this must be incredibly frustrating, it's definitely not the first time this has happened. If I were in your shoes I would find a local independent shop and ask how they would handle it. Likely a replacement harness. Then tow it over and have the work done, assuming prices are reasonable. Doing this without the proper diagnostic tools and equipment would really suck. It will get done much faster this way, and ready for you to enjoy this summer. All the best!

[Steeler]

Attachment 2608614

Originally Posted by billsz4

Uh oh!

Pulled the car cover off of my wife’s 2005 3.0 and found the 1 year old battery dead. Replaced the battery and started her up, only to find a number of dash lights (I assumed these were related to the low voltage/dead battery). ABS, Brake, DCS. Popped the hood and found, well, a huge pile of leaves (something clearly was very comfortable in there). After cleaning it out, noticed a multi plug with several wires chewed through!

Where do I go from here? Do I need a new harness? Other ideas/solutions?

That looks like a ground block to me.

[billsz4]

If I need a harness, and idea what that might cost?

I am seriously considering splicing the wires to see where that gets me. Any downside to this approach?

[Steeler]

I am pretty certain they are all grounds. Match em up and splice would be my first thought.

Be sure and solder, not twist together.

[Efthreeoh]

If you are not well experienced in repairing automotive electrical systems, my advice is take the car to a professional. Rodent damage is covered by comprehensive coverage on your insurance policy. You'll have to pay the deductible, which hopefully you chose a low amount.

[Gamb1t]

That first photo with all the leaves gives me the creeps. I wonder what other wonderful surprises lurked under that hood. I remembered coming across a 3.0i's engine bay that resembled a national park diorama, the oil cap has this gooey mess and coolant reservoir has stuff floating around that reminded me of abandoned swimming pools.

Good luck with revitalizing your wife's car.

[Clearancediver]

That is a "grounding" point. As dbarton62 said… matchup and solder together. Make sure you use heat shrink over the new joints to prevent corrosion issues down the line.

This is what any tech is going to do to repair this issue.

[unluky]

100% match them up and fix yourself. That could be hundreds for a professional to fix for you. Strip them and twist tie them together to make sure all is well and run her a bit - if so take then apart again and solder/heat wrap them and call it good. It's a ground - so either it's connected or not. Don't sweat it - these cars on not princesses.

And the 2 times I had a dead battery in mine, I got dash lights too - so they MAY not be related. Might went back off with a short drive and a restart. Needs fixed either way though.

Good luck!

[billsz4]

Thanks for all the input. Sorry for being slow to respond - I’ve been involved with my other cars and my wife’s Z4 (which she never drives) had to wait.

I twisted the wires together (I’ll eventually solder, or have someone else do it). The car seems to drive fine, but I have yellow BRAKE, ABS, DTC and low tire pressure warnings. I’d like to determine if these dash lights are related to the chewed wires or something else is going on.

I only have a cheap code reader (I’ll need to get something more sophisticated or bring it to my mechanic), but there are no stored codes. Does that rule out a speed/abs sensor or abs module? Or is it that these failures don’t normally throw codes? I thought my cheap code reader would give me some indication, but wouldn’t allow me the specificity to know diagnose the problem (eg which speed sensor). Appreciate any/all thoughts. Thx

[Steeler]

Did you clear all those codes?
Did those codes return if you did?

[billsz4]

The dash lights are on, but when I use the code reader it tells me that there are no faults. Even if I use the “clear codes” function, all of the dash lights immediately reappear at startup. Without a good code reader it’s hard to tell what’s going on, but Im hoping to get clues as to whether they are real issues or related to the chewed wiring.

[billsz4]

I’m looking at a Creator C110 code reader which should help me diagnose whether I have a wheel speed sensor, ABS sensor, or ABS module issue. Can anyone confirm that this scanner will meet my needs?

[jwolf]

The LAUNCH-CRP429C scanner is really nice. Works with most makes of cars. Has ability to connect to wifi, email what it finds wrong etc, real time data streams for sensors and such. I can't imagine not having it.

[Dynamics99]

Splice the wires. Use either heat shrink or tesa tape to wrap them to prevent soft damage. Make sure to use solder. If you dont feel comfy I would take it to an Indy that deals with BMWs. Once you get the wires sorted then you could diagnose the holy trinity of DSC. There are a couple of sensors that link the DSC. Check if there is any moisture on the passenger carpet because the Yaw Sensor is located right in the passenger footwell.


The creator scan tool works but I doubt you would truly be able to clear codes since the broken wires might be producing an error back to the Kombi. I have the Creator C310+. Another solution would be to use INPA to diagnose. If you don't have the software or cables see if someone could help you locally.

[billsz4]

Thanks for the suggestions. I spoke to my Indy mechanic (he’s doing struts on my MB S600) and he said soldering/splicing is something he could do. I’m planning to swap the MB for the Z4 and let him do the work. Twisting the wires together hasn’t allowed me to clear the coda, so I’m guessing that’s something separate that can’t be diagnosed without the splice and the right scanner/software which he has. We agreed he’d do the splice, diagnose the lights, and we'll see where we are. Once I know more I’ll post back. Thanks also for the scanner recommendations.

[billsz4]

Update: I rec’d my Creator 310+ scanner today (thanks Dynamics99 for the suggestion!) and wanted to see what it could tell me. As expected, I had a number of codes so I went through and cleared everything. When I started the car I immediately rec’d the DTC and yellow BRAKE mssg. Backed the car out of the driveway and took it around the block. The first time so depressed the brake pedal I could feel the brake pedal pulsing (abs engaged) even though I was going 10 mph. Then the abs and low tire pressure lights came on. After that no more pedal pulsing. I went in and read the codes and had:
- 5D92 wheel speed sensor pulse gear
- 5E21 pressure sensor 2

Prior to resetting the codes I had both of these, plus the SAS code and others.

I realize I can’t know for sure until the grounding issue above is resolved, it based on this info it seems I might need a left front wheel speed sensor. What’s Pressure Sensor 2? If I wanted to take this on while I wait for my Indy (my MB is delayed) can someone suggest replacement parts and any “how to” info? I will of course do the typical YouTube search. I did check Rock Auto for parts and I’m a little confused re “pulse generator without wire”, “input shaft” and “output shaft”. How do I tell what I need?

[billsz4]

Watched a couple of videos - speed sensor seems straight forward. Ordered a Bosch replacement for $37. The pressure sensor also looks like a remove and replace, although getting access might be a PITA. Ordered one for $100. Both will arrive after the weekend - will plan to replace and see where that gets me. For $140 if I can replace them without much difficulty it will be $$$ well spent.

Before I jump in - anything else I need to know or should be concerned about?

[billsz4]

As expected - I replaced the speed sensor easily enough (the 5mm hex bolt was pretty rusted) but I cannot access the pressure sensor. There are two sensors, and of course it’s the one closest to the firewall which is nearly impossible to reach. I got a 27mm open end on it, but could only move it a couple of degrees, There’s not enough room to reposition the wrench to keep it moving. Purchased a 27mm flexible box wrench (one with a knuckle to get the angle right) but cannot get the wrench on the sensor due to the wall thickness of the wrench. Does anyone have a suggestion on how to remove the sensor? I was hoping to replace it without losing too much brake fluid to avoid having to bleed the brakes and abs unit.

[Steeler]

Originally Posted by billsz4

As expected - I replaced the speed sensor easily enough (the 5mm hex bolt was pretty rusted) but I cannot access the pressure sensor. There are two sensors, and of course it’s the one closest to the firewall which is nearly impossible to reach. I got a 27mm open end on it, but could only move it a couple of degrees, There’s not enough room to reposition the wrench to keep it moving. Purchased a 27mm flexible box wrench (one with a knuckle to get the angle right) but cannot get the wrench on the sensor due to the wall thickness of the wrench. Does anyone have a suggestion on how to remove the sensor? I was hoping to replace it without losing too much brake fluid to avoid having to bleed the brakes and abs unit.

That sensor is a bear for sure.

I have several metric wrenches that I have cut in half for tight spots, takes more body torque to crack a tight fastener/sensor etc. but you get more rotation.
Wrap the cut end with electrical tape.

I bleed the system for safety's sake after brake or clutch work, regardless how minor.

[billsz4]

dbarton62 - thanks for the suggestion. I considered cutting the wrench, but it might have to be cut so small that I’ll lose all the necessary leverage. The good news is I can cut the 27mm and use a 1-1/16 when more torque is required since they’re virtually identical. I’ll have to go take another look to see how much clearance I’d have.

Tried a 1-1/16 deep socket, but there’s no way I can get a 1/2” ratchet on it.

I also considered removing the other sensor which would provide more access - but I’d need to find a way to plug the port while working on the other sensor.

Are there any other alternatives? I can’t imagine that the dealer uses a cut wrench to change the sensor.

[billsz4]

Here’s my last ditch effort post for ideas on how to remove the pressure sensor. I checked the clearance to consider cutting a wrench in half - it would have to be 2-3” max - I doubt I’ll be able to get any torque on something that small. Any other ideas from anyone that’s removed this sensor? If not - early next week it goes to my mechanic.