A209 2008 CLK 280 Fault Codes P0128, P0856

[richardgr88]

Morning All

So I was driving home from my friends house at about 10PM last night when the Engine light came on my fairly new to me 2008 CLK 280. Being a 280 I have checked the engine number of the M272 engine and it looks to be quite past the balance shaft issue.

I see P0128 refers to the coolant thermostat however I'm unsure if the P0856 is also related to the coolant system or if it's related to the traction control system. It was relatively cold last night during the journey. I have noticed on the log of temp for the coolant this morning it seems to be fairly stead and regulated.

Below is a screenshot from the Torque app on my tablet showing the fault codes, and also a screenshot of the coolant temp for my journey into work this morning.

I have cleared the codes a short while ago and will have to see how the journey on the way home goes - this is the first time this has happened.

Any input much appreciated

Richard

 

[ftb]

A lot of aftermarket 'apps' give a very generic description for faults. Sometimes contradictory, e.g. other car maker's description.

How many miles on the vehicle? Not unusual for thermostats to go. Have a proper Merc/Star diagnostics done. It should pinpoint the problem.

 

[whitenemesis]

The coolant temp looks a little low to me, should be closer to 90c?

 

[ftb]

The coolant temp looks a little low to me, should be closer to 90c?

He said it was a cold night... No idea on the journey length either... could be short?

 

[richardgr88]

Thanks for the responses. The car is on almost 58k. I'd agree I think the coolant temp is quite low. Think the journey was about 20 miles on national speed limit roads. Ambient temp was around 0. It wasn't a particularly harsh drive but not driving like a granny either if that helps.

 

[whitenemesis]

It's a petrol, my CLS would reach 90c within a very short distance ~1 mile at most.

The C270cdi on the other hand wouldn't get hot at all in the cross town drive...

 

[richardgr88]

I will see how the journey home goes, hope to log it again with the torque app.

Might be worth mentioning this mornings journey (when the data for the graph was logged) the lowest temp I saw was -5 but equally I think the coolant temp should be higher than it is reading.

Perhaps I'm in the market for a new thermostat.

 

[richardgr88]

Graph showing coolant temp, fuel level, air intake temperature

 

[richardgr88]

This evenings drive home. The light has not come back on again. It looks as though the thermostat is regulating the temperature but the reading seems a bit on the low side. Fuel economy wasn't bad given the outside temperature. Hope this is at least somewhat interesting Quite like looking at and analysing data.

 

[Codger49]

I too, think your coolant temp is rather low. It's maybe affecting your mpg as well, I would expect 30 or so from 20 miles at an average around 30 mph

 

[richardgr88]

And I thought I got away with it.....at least until the drive home on Wednesday. The engine light has come back on. I wish I had taken note of the exact time as I could have looked on the graph I was recording at the time.

Booked into the garage for next week. Taking it to my local trusty indy, albeit the first time they've looked at this car for me, they've seen others plenty of times.

I would replace the thermostat myself but seeing as this car is very new to me and I can't be doing with draining the coolant and taking of the pulley during the dark evenings I'll let the garage do it.

Fingers crossed a new thermostat will fix things. Have decided to drive my other car (not so nice as the CLK but an MG TF!) don't want to risk the thermostat getting stuck closed.

Anyone had any experience of an AA Dealercare warranty? - my current opinion is it isn't worth the paper it is written on but no harm in trying to claim, 3 months were included free....and no matter what they say I'm not taking it to Halfords. I wouldn't trust them with the MG and that's worth nothing.

On a positive note if a new thermostat can boost the MPG by a couple that would be good.

 

[Auto-mobile]

Thank you for making my iPad crash....

Thermostats are common on your engine.

 

[richardgr88]

Sorry about the iPad crash, seemed to work ok on my phone - I like posts with lots of pictures. I like to think they help others.

Car has been to the garage and they've replaced the thermostat and fixed my leaky front tyre which was a separate issue.

Have nearly died though when they told me the cost of the thermostat. £214 for the part alone :-O....I've used this garage loads of times and had a fairly major service on another vehicle with a cambelt and the total bill came to under £500.

I nearly brought a thermostat from Eurocar parts for about £40 something after 30% off. Perhaps they brought a genuine Merc one. What would you guys expect one to cost?

I know Merc = premium vehicle but **** me! Wish I'd have brought the Eurocar parts one now and had a go myself.

 

[richardgr88]

An update:

Car is back from the garage and running well. Not sure if it was the garage trying to fleece me or their supplier. Wanted £214 for a thermostat! Was an FTK212 which I have Google and looks like they're about £130 and are allegedly OE quality. Not a nice feeling.

Contacted Merc this afternoon for a price and they said £118 (inc VAT).

Queried this at the garage although don't feel I should have to and they spoke to the supplier and the thermostat was reduced to the £130.

Now the car heats up a treat the weather has changed! Typical. Fingers crossed for a few extra MPG.

I suppose all in all the job probably worked out the same cost as labour would have been significantly more at Merc. Perhaps lost faith in this indy now.

 

[Hamble Flyer]

This thread has prompted me look at the coolant temp in my 209 albeit with a 1.8 M271 engine. During a 30 min run in town today it only just crept above 80 and mpg was around 27. I have had the CLK for only 3 weeks or so and the 90 % urban driving of a couple of hundred miles shows about 28 mpg average.
Is this mpg about right for the car?
I'm off on a longer fastish A road trip tomorrow so will get a better picture of fuel consumption.
Can anyone provide a quick explaination why lower coolant temp has an adverse effect upon fuel economy......just curious.

 

[richardgr88]

Hi there, awesome a fellow 209 owner. With mine when the check engine light came on it was barely even making 80 and then falling again. Today it was clearly over 80.

My fuel economy on my run to work is generally late 20's, best I've ever seen is about 34 which was on a long motorway run of a few hundred miles.

The low coolant temp has an adverse effect on the fuel economy because the car thinks the engine is cold and never really gets up to temperature so runs it rich as per the warming up routine, therefore using more fuel....or at least that's my understanding of it.

I'd like to think a 1.8 could get more than 27 but maybe I'm living in a dream world.

 

[GP801]

This thread has prompted me look at the coolant temp in my 209 albeit with a 1.8 M271 engine. During a 30 min run in town today it only just crept above 80 and mpg was around 27. I have had the CLK for only 3 weeks or so and the 90 % urban driving of a couple of hundred miles shows about 28 mpg average.
Is this mpg about right for the car?
I'm off on a longer fastish A road trip tomorrow so will get a better picture of fuel consumption.
Can anyone provide a quick explaination why lower coolant temp has an adverse effect upon fuel economy......just curious.

I have a 2003 209 1.8litre 200k. In normal mixed use it returns around 32-33mpg, 37ish on a steady run. The best I saw was 42 mpg on a long 1000 mile run to Italy. All according to the computer thing.

 

[fabes]

Hi there, awesome a fellow 209 owner. With mine when the check engine light came on it was barely even making 80 and then falling again. Today it was clearly over 80.

My fuel economy on my run to work is generally late 20's, best I've ever seen is about 34 which was on a long motorway run of a few hundred miles.

The low coolant temp has an adverse effect on the fuel economy because the car thinks the engine is cold and never really gets up to temperature so runs it rich as per the warming up routine, therefore using more fuel....or at least that's my understanding of it.

I'd like to think a 1.8 could get more than 27 but maybe I'm living in a dream world.

Low 20's around town, low 30's on a run is what I am getting from my Clk280
The 1.8s are quite a bit better (on fuel)

I haven't had a thermostat issue (yet......)

 

[Ted]

Hi there, awesome a fellow 209 owner. With mine when the check engine light came on it was barely even making 80 and then falling again. Today it was clearly over 80. My fuel economy on my run to work is generally late 20's, best I've ever seen is about 34 which was on a long motorway run of a few hundred miles. The low coolant temp has an adverse effect on the fuel economy because the car thinks the engine is cold and never really gets up to temperature so runs it rich as per the warming up routine, therefore using more fuel....or at least that's my understanding of it. I'd like to think a 1.8 could get more than 27 but maybe I'm living in a dream world.

The 1.8 has no problem getting more than 27 and is a great long distance cruiser.


View attachment 60918

 

[4life211]

The 1.8 has no problem getting more than 27 and is a great long distance cruiser.

why have you set to C??