CLK non-starter with error code P0112
09-13-2018, 04:10 AM
#1
Newbie
Thread Starter
CLK non-starter with error code P0112
Strange issue with my CLK today. Headed off to work and car started fine, then 2 minutes up the road, I remembered that I'd forgotten something so headed back home. Pulled up outside and ran in the house to grab what I needed (was in the house all of 2 minutes) and then came back out, jumped in the car, and now I just get this noise of presumably the starter motor trying to start the engine, but doesn't actually crank.
I have an ELM327 WiFi OBDII gizmo and an app on my phone called "FourStroke" which pulls up the error codes on the car, and I'm getting a P0112 error code.
Feel like I'm going down the rabbit hole with this one as so far from looking on google, from what I can tell it could be the MAF sensor, the CPS, the fuel pump or an electrical fault! :-(
What's making me think that maybe it's not the CPS is that it doesn't start regardless of whether the engine is hot or cold, and I've read that normally if the CPS is faulty, it will normally work if you let it cool down for half an hour or so. It makes no difference and still won't start even after leaving the car for two hours.
What's making me think its' not the MAF sensor, is that most people say a MAF issue really affects vehicle performance, but won't stop the car from actually starting.
I guess it could be the fuel pump, but wouldn't that bring up a different fault code? I can clear the P0112 code with the app, then turn the key, hear the noise and the error code comes straight back again.
I checked the fuse in the boot for the fuel pump and that looks fine. I also swapped the relay for another identical one I borrowed from the fuse board under the bonnet (Hella 12v 4RA 002 542 26 19) that does another job, but that still didn't work so doubt it's that.
I uploaded a quick video of the noise (unfortunately the sound isn't great - Also please ignore the 3-4 "dunk" noises at the start of the video as that's an unrelated issue of a plastic cog hidden away behind the dash that controls air-con direction...apparently a common fault on the CLK's)
What do you guys think?
What I'm thinking I'll do is firstly change the CPS (this one)
and if that doesn't work, then change the MAF (this one)
and either of those don't work then possibly a new fuel pump?
Any help/advice would be much appreciated!
I have an ELM327 WiFi OBDII gizmo and an app on my phone called "FourStroke" which pulls up the error codes on the car, and I'm getting a P0112 error code.
Feel like I'm going down the rabbit hole with this one as so far from looking on google, from what I can tell it could be the MAF sensor, the CPS, the fuel pump or an electrical fault! :-(
What's making me think that maybe it's not the CPS is that it doesn't start regardless of whether the engine is hot or cold, and I've read that normally if the CPS is faulty, it will normally work if you let it cool down for half an hour or so. It makes no difference and still won't start even after leaving the car for two hours.
What's making me think its' not the MAF sensor, is that most people say a MAF issue really affects vehicle performance, but won't stop the car from actually starting.
I guess it could be the fuel pump, but wouldn't that bring up a different fault code? I can clear the P0112 code with the app, then turn the key, hear the noise and the error code comes straight back again.
I checked the fuse in the boot for the fuel pump and that looks fine. I also swapped the relay for another identical one I borrowed from the fuse board under the bonnet (Hella 12v 4RA 002 542 26 19) that does another job, but that still didn't work so doubt it's that.
I uploaded a quick video of the noise (unfortunately the sound isn't great - Also please ignore the 3-4 "dunk" noises at the start of the video as that's an unrelated issue of a plastic cog hidden away behind the dash that controls air-con direction...apparently a common fault on the CLK's)
What do you guys think?
What I'm thinking I'll do is firstly change the CPS (this one)
and if that doesn't work, then change the MAF (this one)
and either of those don't work then possibly a new fuel pump?
Any help/advice would be much appreciated!
09-13-2018, 09:59 AM
#2
MBworld Guru
P0112 is a problem with the intake temperature sensor, which is part of the MAF sensor. This will not prevent starting. Check fuel pressure. It may also be a bad CPS.
09-15-2018, 02:53 PM
#3
Newbie
Thread Starter
Well I committed to changing the CPS and what a nightmare it’s turning out to be to swap it out!
First of all, as I’m sure many of you know, it’s a nightmare to get at. I found a “how to” that suggested using a 1/4 12in extension bar but for the life of me I cannot see how this would be physically possible as the torx screw holding down the CPS is below the plastic “D” connector on the CPS as you aim the bar down so there was no way I could get the 8E female torx socket on to it.
Anyways after more searching around I found a far better method which is to use 2x 1/4 6in extension bars connected together with a 1/4 universal joint adaptor. That finally got me on the screw and I managed to get the thing out.
The next issue is the CPS itself. It’s like it’s been superglued in! :-(
I spent around 2 hours trying to pry the thing out. I even ordered these extra-long 400mm needle nose pliers to yank it out but it won’t budge at all. Nothing. Won’t twist, won’t rock, literally stuck fast.
Will try some WD40 penetrant tomorrow all round it tomorrow, but am slowly starting to worry this will be a dropped transmission job. I dread to think what that will cost me :-(
First of all, as I’m sure many of you know, it’s a nightmare to get at. I found a “how to” that suggested using a 1/4 12in extension bar but for the life of me I cannot see how this would be physically possible as the torx screw holding down the CPS is below the plastic “D” connector on the CPS as you aim the bar down so there was no way I could get the 8E female torx socket on to it.
Anyways after more searching around I found a far better method which is to use 2x 1/4 6in extension bars connected together with a 1/4 universal joint adaptor. That finally got me on the screw and I managed to get the thing out.
The next issue is the CPS itself. It’s like it’s been superglued in! :-(
I spent around 2 hours trying to pry the thing out. I even ordered these extra-long 400mm needle nose pliers to yank it out but it won’t budge at all. Nothing. Won’t twist, won’t rock, literally stuck fast.
Will try some WD40 penetrant tomorrow all round it tomorrow, but am slowly starting to worry this will be a dropped transmission job. I dread to think what that will cost me :-(
09-15-2018, 10:42 PM
#4
MBworld Guru
Try PB Blaster - I've had better luck with it than WD-40 for stuck parts. Since it's only plastic, there should be no oxidation holding it in place. In fact, I don't even think it has an o-ring on it.
11-28-2018, 10:15 AM
#5
Newbie
Thread Starter
Update on the nightmare I've had with the car. Couldn't get the CPS out for love nor money. After spending the best part of a week trying different things I finally gave up and had the car towed to a garage.
They had to drop the transmission to knock it out and put the new one in, however that made no difference, and the car still wouldn't start. The garage believed it to be a faulty ECU, but couldn't find anyone in the UK who would have a go at repairing it, so they shipped it off to an ECU specialist in Germany.
After a week, it got shipped back to the UK....plugged it in....still not working, so the garage called the German company, who were insisting that the ECU was fixed...in the end they agreed to taking a second look at it, so the garage shipped it back to Germany......The latest I heard was that it then got shipped elsewhere to another place in Germany, and now it's back in the UK, but from what the guy at the garage tells me, he's not convinced they have fixed it, but there's no way he can prove it, as when it gets plugged in it still doesn't work.
Have no idea where I go from here.....it's been over 2 months now since I've had my car!
Is there any point throwing more money at this?
Anyone had similar issues with their ECU?
Any suggestions greatly appreciated!
They had to drop the transmission to knock it out and put the new one in, however that made no difference, and the car still wouldn't start. The garage believed it to be a faulty ECU, but couldn't find anyone in the UK who would have a go at repairing it, so they shipped it off to an ECU specialist in Germany.
After a week, it got shipped back to the UK....plugged it in....still not working, so the garage called the German company, who were insisting that the ECU was fixed...in the end they agreed to taking a second look at it, so the garage shipped it back to Germany......The latest I heard was that it then got shipped elsewhere to another place in Germany, and now it's back in the UK, but from what the guy at the garage tells me, he's not convinced they have fixed it, but there's no way he can prove it, as when it gets plugged in it still doesn't work.
Have no idea where I go from here.....it's been over 2 months now since I've had my car!
Is there any point throwing more money at this?
Anyone had similar issues with their ECU?
Any suggestions greatly appreciated!
12-05-2018, 12:18 AM
#7
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Join Date: Aug 2013
Location: Dallas, TX
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2006 CLK350 Cabriolet (A209)
Update on the nightmare I've had with the car. Couldn't get the CPS out for love nor money. After spending the best part of a week trying different things I finally gave up and had the car towed to a garage.
They had to drop the transmission to knock it out and put the new one in, however that made no difference, and the car still wouldn't start. The garage believed it to be a faulty ECU, but couldn't find anyone in the UK who would have a go at repairing it, so they shipped it off to an ECU specialist in Germany.
After a week, it got shipped back to the UK....plugged it in....still not working, so the garage called the German company, who were insisting that the ECU was fixed...in the end they agreed to taking a second look at it, so the garage shipped it back to Germany......The latest I heard was that it then got shipped elsewhere to another place in Germany, and now it's back in the UK, but from what the guy at the garage tells me, he's not convinced they have fixed it, but there's no way he can prove it, as when it gets plugged in it still doesn't work.
Have no idea where I go from here.....it's been over 2 months now since I've had my car!
Is there any point throwing more money at this?
Anyone had similar issues with their ECU?
Any suggestions greatly appreciated!
They had to drop the transmission to knock it out and put the new one in, however that made no difference, and the car still wouldn't start. The garage believed it to be a faulty ECU, but couldn't find anyone in the UK who would have a go at repairing it, so they shipped it off to an ECU specialist in Germany.
After a week, it got shipped back to the UK....plugged it in....still not working, so the garage called the German company, who were insisting that the ECU was fixed...in the end they agreed to taking a second look at it, so the garage shipped it back to Germany......The latest I heard was that it then got shipped elsewhere to another place in Germany, and now it's back in the UK, but from what the guy at the garage tells me, he's not convinced they have fixed it, but there's no way he can prove it, as when it gets plugged in it still doesn't work.
Have no idea where I go from here.....it's been over 2 months now since I've had my car!
Is there any point throwing more money at this?
Anyone had similar issues with their ECU?
Any suggestions greatly appreciated!
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12-05-2018, 10:10 AM
#8
MBworld Guru
I had the same issue and my car was in the shop for several months. At first it would turn over but not start, then sometimes it would start but only sporadically. My fuel pump was replaced, not the problem. A rear something, an electrical component was replaced, not the problem. I was asked to bring in the extra key in case it was a faulty key/ignition issue, not the problem. I kept asking if it could be the CPS and was always told no, that a CPS issue would throw a code which mine never did.
A bad CPS does not always throw a code. In fact, it more often does not.
Finally they replaced the ECU and that fixed it. I had to escalate the problem to MB and get my dealers regional involved because they just kept throwing parts at the car. I never understood why the fuel pump pressure couldn't be checked at the rail before installing a new pump? If this hadn't happened to me I would have had a hard time believing an entire MB service dept could not isolate why a car in this situation would not start. I did insist on keeping all my original parts that were removed, you might want to consider this too. Good luck.
12-05-2018, 10:11 AM
#9
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2006 CLK350 Cabriolet (A209)
The electrical part I couldn’t remember was a rear SAM unit. I started a thread to discuss my issue and pasted a link to it below, maybe it will help you. Take care - Mike.
https://mbworld.org/forums/clk-class...r-sam-bad.html
https://mbworld.org/forums/clk-class...r-sam-bad.html
12-05-2018, 10:15 AM
#10
MBworld Guru
Mike, that is ridiculous that they replaced the fuel pump and rear SAM before the ECU. Fuel delivery and current draw on the pump can be checked easily, and that would have ruled out both the SAM and the fuel pump. Have you gotten any relief from MBUSA on this?
12-05-2018, 11:36 AM
#11
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2006 CLK350 Cabriolet (A209)
Hi Rodney, I did get a substantial discount on all of what I and the MB regional considered needless work/parts. But I will never get my time back wasted on resolving this not to mention the aggravation.
