Starter replaced but still no crank no start

[bmehi]

Hi everyone,

I’ve been having an issue that I figured was the starter motor and have replaced it but it changed nothing.

If anything it’s throwing up more codes now than it did before.

I had codes: A0B4 CAS engine start, starter operation
A0C1 CAS output, terminal 50
A0C2 CAS output, terminal 50 RS

Now I had these codes before I started, but since then I have 278D BSD message, alternator missing, 2B23 DME idle actuator governor monitoring bank 1, 2B15 DME throttle actuator governer monitoring bank 1, and 2B16 DME throttle actuator governer monitoring bank 2.

Definitely something electrical, had some work done a few months back and the guy said the engine ground strap was replaced. Also don’t mind so much that the starter was replaced as it looked fairly shoddy when it came out so peace of mind there for the future!

Could this be the CAS module has failed? Or something like the clutch switch?


When I go to start the car, all electrics come on no problem and I just have a ! Showing on the dash. It doesn’t click or attempt to crank at all. The fuel pump primes and if anything seems to prime for a long time.

Has anyone come across anything like this before? Are there any simple tests I can do to try figure it out? Could a bad battery still let the car lock/unlock and interior lights? I figure it’s not battery related as nothing flickers when I press start.

Any info or past experiences would be amazing!

[Ajolives]

I’d check the fuses and maybe try starting with a jumper box or another car (if haven’t done so already). Sounds like it could be a weak battery.

[amrazM]

Im assuming the engine turns by hand? Take a visual check and verify the clutch sensor is in place on the master cylinder.

Then use a scan tool to verify that the clutch press signal is being received, if not chances are you have a failed sensor or a deeper issue here. Usually on a 6mt car if you click the start button several times with the clutch not depressed you get the warning in the cluster that indicates press clutch to start.

[bmehi]

Originally Posted by Ajolives

I’d check the fuses and maybe try starting with a jumper box or another car (if haven’t done so already). Sounds like it could be a weak battery.

Battery isn’t too old, have a CTEK on it tonight to see if it’ll make a difference, was a bit low when I put it on, but if it was the battery wouldn’t lights flicker etc?

Any idea if being grounded off another car would help if engine ground strap is kaput?

[bmehi]

Originally Posted by amrazM

Im assuming the engine turns by hand? Take a visual check and verify the clutch sensor is in place on the master cylinder.

Then use a scan tool to verify that the clutch press signal is being received, if not chances are you have a failed sensor or a deeper issue here. Usually on a 6mt car if you click the start button several times with the clutch not depressed you get the warning in the cluster that indicates press clutch to start.

Had a look at this earlier, all seems right and the scan tool was showing the signal being received when the clutch was pressed. The ! On the dash seems to pop up instantly but even in idrive there was no warning.. I did eventually get a low battery warning for the first time today but was figuring that was from all my messing with trying to get it to start.

[1messedupZ4M]

Symptoms sound like a bad engine ground strap.

Use a jumper cable from the engine lifting point under the intake plenum to the ground spot around the coolant bottle. Pull the clamp back and forth on each surface to expose some fresh metal for the leads to bite into.

[charliev68]

CAS is probably acting up. You said you have a code for it.

[bmehi]

Well.. just to make a note for anyone who finds this in the future - it was the ground strap from engine to body. I’m not 100% sure the starter wasn’t on the way out as well somehow at the same time but that’s probably unlikely.

Problem was the coating on the engine lift hook preventing it from being usable as an alternative ground. Got a multimeter and decided to check the battery jump point and the hook and it wasn’t holding voltage so had a closer look and hadn’t realised it wasn’t bare metal.

Saw a pipe with a metal end down below the oil cap and decided to chance it with the jump lead from there to the grounding point for jumping the car and it fired up straight away.

Thought I’d just add this as I haven’t come across any other information regarding the ground straps causing all of the codes I had in my original post.

Starter was fairly rough looking and rusty so glad I’ve changed it while I was in there though maybe I didn’t have to this time. (For anyone in Europe I used eurostarter.de for €300 compared to BMW wanting €700 for a starter)

[Redd]

Thanks for updating with fix. What was the ground strap part number pls?

[Mhuynh1031]

Originally Posted by Redd

Thanks for updating with fix. What was the ground strap part number pls?

Based on E90 328XI

Attach is the ground strap location. It's on the engine cover bolted to the body. You can use what ever strap but use a decent gauge one. Mine looks rough.

My current problem Car has issues starting (A0B4 Error code)

My symptoms:
-sometimes no starts
-have to charge the battery to get it started (needed full battery or nearly full to start)
-A0b4 error code - ista says fault is set when terminal 50 from cas is ok, but the engine still doesnt start. BMW wanted $2687.36 to replace.

After replacing the starter

Symptoms
-A0C1 + A0C2 - car access system codes
-car will not let go of the key.

Tests/process
-replaced the aux relay (behind glove box on passenger, BMW part number 61-36-6-901-469) Same code no change
-checked all fuses, it was fine
-with the starter out and everything disconnected to it, I pulled the codes, no CAS issue but still wont let go of the key
-battery was at 45% so i charged it 99%, still no change
-looked at the ground strap, it looks rough, burnt and I could see some burning on the shielding of a brake line.

Hypnosis
-Bad ground (at engine, light gauge or below starter which is gauge 2). Replacing the engine ground first and seeing what happens since its the most obvious bad one.

Tips and tricks

If you want to quickly check fuses, get a probe with a light and hook it up to the ground. When the engine is on, you can quickly check the fuses, there an exposed part where you can just touch it and it will light up.

There is a 2nd strap under the car that is usually green, I have included an example. But that is usually fine.

I have also included the a picture of how the positive cable attaches to the alternator to the starter.

[Mhuynh1031]

For the next me that has issues

Update - Car starts now.

Replaced the ground strap with a GM one from amazon (part number 15179982) because it came overnight. Autozone only has gauge 4 wire. It also has shielding, which helps from the heat.

Final fix:

-Bad engine ground
-bad starter

Symptoms before
-no starts
-low battery
-after replacing starter, cas issue. Car will not let go of the key
-still no starts

other errors codes on the car

55c3 - I think its from the battery being disconnected from the car for a week. It has to relearn.

C54c6 - I still have to reset the transfer case oil change. FRM was bad and it was replaced on warranty from the dealer. It needed communication to it to reset the light.