Codes help

Devon Z

Devon Z

Zorg Guru (IV)
Supporter
British Zeds
Joined
Jan 1, 2012
Points
169
Location
Brixham, Devon
Model of Z
99 2.0 Individual
So first off no lights no issues driving/braking just thought I would try my recently acquired code reader, pulled these that will not clear, well it says they’ve cleared but when I rescan still there.
IMG_4970.jpeg
Pugged into round socket under the bonnet.

Another thing can’t find find any details under those 2 digit code numbers on the internet, my other code readers for my other cars record PO 4 digit code numbers.

Any help appreciate.
 
I googled your codes and got…


A BMW Z3 code 94 (ASC/DSC: CAN data fault from DME/DDE) means your traction control module (ABS/ASC) has lost communication with the engine computer (DME/DDE) over the Controller Area Network (CAN bus). Your traction control light (and often the ABS/Brake lights) will illuminate. [1, 2, 3, 4, 5]
The most common causes and how to address them include:

1. Faulty ABS/ASC Module
The module itself is a very common failure point on the Z3. The internal solder joints or the main electronic board degrade over time. [1, 2]
  • The Fix: Many owners opt to send the black electronic portion of the module out to specialized repair shops to be rebuilt or resoldered rather than buying a brand-new unit. [1, 2]
 
2. Wiring or Connector Issues
Corroded pins at the ABS module block or a break in the CAN bus wiring harness can cause data loss. [1, 2, 3]
  • The Fix: Inspect and clean the main electrical connector to the ABS/ASC unit. Trace the wiring loom going from the DME/DDE to the throttle motor/module and check for frayed wires or poor grounds. [1, 2, 3]

3. DME (Engine Computer) Problems
Internal failures or erratic signals in the DME itself will disrupt communication. [1]
  • The Fix: Read live engine data using BMW-specific diagnostic software (such as 1780706383568.webp⁠INPA Software) to ensure the engine isn't dropping RPM signals or throwing other faults (like a bad crankshaft sensor) that cascade into a CAN error. [1, 2, 3]
 
In the same ‘conversation’ I inputted your other two codes


BMW Code 76 (Speed Sensor, Signal Interference) indicates that your ABS/ASC (or DSC) module is receiving an unreadable, distorted, or heavily interrupted signal from one or more of the wheel speed sensors. Unlike a "sensor circuit open" fault—which means the sensor is totally dead or unplugged—"signal interference" means the sensor is sending data, but the electronic waveforms are too erratic for the computer to safely calculate vehicle speed. [1, 2, 3]
This code pairs perfectly with your previous DTC 94 CAN data fault. If the ABS module cannot figure out how fast a wheel is turning due to interference, it cannot broadcast stable speed data to the engine computer (DME) over the CAN bus network, triggering both codes simultaneously. [1]


Root Causes of Signal Interference
The "interference" can be either mechanical (physical debris disrupting the magnetic reading) or electromagnetic/electronic (bad wiring or internal sensor decay): [1]
  • Rust and Debris on the ABS Tone Rings (Most Common): The wheel speed sensor reads a slotted metal ring (tone/reluctor ring) attached to the spinning wheel hub or driveshaft. Over time, rust chips, road grit, or metallic brake dust fills the gaps or pushes against the sensor, corrupting the magnetic pulse. [1, 2]
  • Swollen Reluctor Rings: Rust can build up underneath the rear reluctor rings, causing the ring to expand or warp outward. As the ring spins, it physically strikes or rubs against the tip of the speed sensor, destroying the signal pattern. [1]
  • Chafed or Failing Wiring Insulation: The wiring harnesses running from the wheel wells to the inner chassis flex every time you steer or hit a bump. Cracked or dried insulation lets in water, inducing voltage fluctuations and electronic interference. [1, 2, 3]
  • Decaying Sensor Internals: The internal copper windings of an older, original sensor degrade with heat cycles, failing to generate a clean alternating current (AC) signal to the module. [1]


Diagnostic Step-by-Step Fix
To resolve the interference code, focus on physical inspection at the wheel hubs:

1. Isolate the Problem Wheel
  • Use diagnostic software like INPA to look at the "Live Data" or "Status" screen for the ABS/ASC module.
  • Drive the car slowly. Watch the individual wheel speed values. The wheel showing an erratic, jumping speed graph (or dropping to 0 mph suddenly) is the source of Code 76. [1]

2. Pull and Clean the Sensor [1]
  • Remove the wheel, locate the sensor on the back of the hub casting, and remove the single 5mm Allen bolt.
  • Carefully wiggle and pull the sensor out.
  • Inspect the tip of the sensor. If it has deep scrape marks, the reluctor ring is warped or swollen and hitting it.
  • Wipe off any metallic sludge or grit clinging to the magnetic tip using a cloth and brake cleaner. [1, 2, 3]

3. Inspect the Tone Ring (Crucial Step)
  • Peer directly down into the empty sensor mounting hole using a flashlight.
  • Have someone slowly rotate the brake rotor so you can inspect the spinning metal teeth of the tone ring.
  • Look for missing teeth, packed rust, or heavy dirt. Use a small wire brush or pick to scrape out debris blocking the window gaps. [1, 2]

4. Replace the Sensor or Harness [1]
  • If cleaning the sensor tip and ring does not clear the code, replace the affected wheel speed sensor. Stick to high-quality or OEM brands (like Bosch or ATE), as cheap aftermarket options frequently suffer from built-in calibration and "signal interference" bugs. [1]
If you don't have a diagnostic scanner to check live wheel data, let me know if your speedometer jumps around while driving, or if this fault only triggers when turning the steering wheel, which can help isolate if it is a front or rear sensor!
 
That’s pretty much what I thought 😳😳😁😁

Wow thanks for the detailed response, you really need to try and sleep at night though 😁

As I mentioned I have no lights, no braking or engine issues at all I was just testing a recently acquired code reader.

Don‘t know how long the codes have been there? I did a scan with a friends Snap on kit about four years ago and there was nothing then.

I’ve got to do annual service and prep for MOT due next month so I’ll do some checks.

thanks again👍
 
If you clear the codes and they come straight back it means the faults are still there, so the issue is 'live'.
 
As said by @Pond your faults may be historic.
Best thing to do when chasing up stuff that may or may not be an issue is to wipe all the cars stored codes go out for a drive see what returns
Also cars can generate ghost codes for equipment not even fitted.
Pretty sure its Stevie ( @Scooblitz ) zed that generates a fault for the rear exhaust flap.
Now the car is a single vanos 2.8 so doesn't have it.

Stephen.
 
So when I clear the codes the code reader says code’s successfully cleared but upon rescan they are still there.

I have enough experience with code readers to know that when you clear codes they generally stay clear till you restart the engine or drive the car which is making me think it may be a fault with the code reader?
 
I have a creator 110 and 310 and i have found sometimes it will clear the codes but not remove them and if i use our
Bosch kts diagnostic tools in work i can clear them
This is probably due to the Creator not being a bi directional device.
Stephen.
 
Devon Z said:
So when I clear the codes the code reader says code’s successfully cleared but upon rescan they are still there.

I have enough experience with code readers to know that when you clear codes they generally stay clear till you restart the engine or drive the car which is making me think it may be a fault with the code reader?
Click to expand...
That's because whatever the faults are can't be cleared as they are there permanently, even though the scanner has cleared them. Usually an open circuit or dead short will do this.

Only faults that need an input of some kind to trigger will stay cleared until you start or drive the car (or receives the input it needs).

I also have a Creator 410. I have the BMW oil temperature sensor plug disconnected all the time (as I have an aftermarket sensor with aftermarket wiring). If I clear the fault code for the sensor it will say cleared but comes back instantly because the fault is always there as there is a permanent open circuit.
I had a faulty ABS wheel sensor the other day. The scanner would clear the fault and put the dash lights out and the fault would only re-appear when the car moved, as it needs that to trigger the fault.

It's unlikely to be a faulty code reader. If it was faulty it would most likely be unable to read the codes in the first place.
 
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A very interesting post and thread, guys. You can guess my Z has the ASC and ABS lights on the dash.
 
ktnez99 said:
A very interesting post and thread, guys. You can guess my Z has the ASC and ABS lights on the dash.
Click to expand...
Most likely a wheel speed (ABS) sensor. Hopefully it's not a yaw sensor (under the passenger carpet), as those are very expensive. Not sure about cars with ASC but with DSC there are two yaw sensors. Both are expensive and susceptible to corrosion from water leaks.
 
Pond said:
Most likely a wheel speed (ABS) sensor. Hopefully it's not a yaw sensor (under the passenger carpet), as those are very expensive. Not sure about cars with ASC but with DSC there are two yaw sensors. Both are expensive and susceptible to corrosion from water leaks.
Click to expand...
Thanks. The car has had all four wheel sensors changed to new. I’m thinking it may be this…?
 
ktnez99 said:
Thanks. The car has had all four wheel sensors changed to new. I’m thinking it may be this…?
Click to expand...
You need a code reader to find out. Expensive guessing otherwise.
 
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