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Discussion Starter · #1 ·
Hello everyone. I bought my first E39 M5 just before Christmas, in fact it's my first BMW. Good start.

It's a 2001 Lemans Blue with 78K on the clock. It's pretty tidy apart from needing a new gear knob and handbrake handle thanks to a wedding ring and the wheels need a refurb.

However, I have already run into problems. The following issue has occurred twice so far and I haven't taken it above 3000 RPM since. When given a bootfull the engine warning light comes on and the car goes into limp mode. If I then turn the engine off and back on again (yes I do work in IT ;)) the car goes back to driving perfectly fine.

I took it to a local BMW specialist and the following fault codes were displayed:

(105) 69 Engine temp signal implausible

(196) C4 Misfire cylinder 1 with cylinder cut out

Whilst connected to the machine it showed no temp anomolies or issues whilst the engine was running though.

Any thoughts? CPS? Vanos solenoids/O rings? Thermostat? As I said, the car seems to drive fine normally.

Any insight would be greatly appreciated.

Cheers
Vin
 

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Hello everyone. I bought my first E39 M5 just before Christmas, in fact it's my first BMW. Good start.

It's a 2001 Lemans Blue with 78K on the clock. It's pretty tidy apart from needing a new gear knob and handbrake handle thanks to a wedding ring and the wheels need a refurb.

However, I have already run into problems. The following issue has occurred twice so far and I haven't taken it above 3000 RPM since. When given a bootfull the engine warning light comes on and the car goes into limp mode. If I then turn the engine off and back on again (yes I do work in IT ;)) the car goes back to driving perfectly fine.

I took it to a local BMW specialist and the following fault codes were displayed:

(105) 69 Engine temp signal implausible

(196) C4 Misfire cylinder 1 with cylinder cut out

Whilst connected to the machine it showed no temp anomolies or issues whilst the engine was running though.

Any thoughts? CPS? Vanos solenoids/O rings? Thermostat? As I said, the car seems to drive fine normally.

Any insight would be greatly appreciated.

Cheers
Vin
69 points to needing a new thermostat. c4 could be the fuel injector or spark plug for cyl #1

Those are the only two codes?
 

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Discussion Starter · #3 ·
Thanks for the reply. Yeah, those were the only two codes that came up.
 

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Thanks for the reply. Yeah, those were the only two codes that came up.
Your poor running issues are mostly caused by the misfiring in cylinder #1. The thermostat is not as big of an issue because it typically gets stuck in the open position causing the car to run slightly cooler than desired. I would focus on the misfiring.

Do you have service records? I would start with spark plugs if they haven't been changed recently. Have the old ones labeled for which cylinder they came from and post good pictures so we can see how each cylinder is running. If the plugs don't solve your problem we can follow the clues from them to drill down to the next issue.
 

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Discussion Starter · #5 ·
Yeah, I'm going to look through the service/maintenance history and replace some stuff that hasn't been done for a while, i.e. air filters, fuel filter, fuel pump, spark plugs and the thermostat. The guy who read the codes did mention coils as well but we'll see.

I'll jkeep you updated. Thanks for the help.

Vin
 

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If I then turn the engine off and back on again (yes I do work in IT ;)) the car goes back to driving perfectly fine.
Heh, heh. Yeah, reboot the sucker.

I concur with russap5. The misfire is causing the car to go into "limp home" mode. Start with the cheap stuff (plugs) and then work up to coil, injector, spark wires, etc.

Michael (also an I/T geek)
 

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Discussion Starter · #8 ·
Nope. It hasn't done it since and I drive it nearly every day. As a matter of course though I am going to replace the thermostat and the pre cat O2 sensors.

Vin
 

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Long shot but since the issue hasn't come back, any chance you had washed the engine bay and water found its way down into something, say into the coil cover and down into and around plug #1 causing the spark to arc?
 

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Discussion Starter · #10 ·
Aaah, now you come to mention it I did have the engine bay valeted about 2 weeks before.....I didn't even think about that.
 
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