check engine light on 98,99 diesels - PeachParts Mercedes-Benz Forum

#1 06-26-2002, 10:18 AM

To our esteemed techs and others who might know,
What functions does the "check engine" light monitor on the 98 and 99 E300 diesels? My assumption is that it is different from the gas cars. I have a light that stays on after engine start. The dealership was unable to determine a cause after a three day stay in the shop.
thanks,
Steve
99 E300turbodiesel, 35k

JimSmith · #2 06-26-2002, 11:04 AM

Steve,

On my car the air mass sensor died and that set off the light on the dash to check engine. I believe mine actually said engine electronics, not just engine, but I could be mistaken. Jim

#3 06-26-2002, 11:28 AM

Jim,
Thanks for your reply. I posted an update to my post on the diesel board which essentially ran "car came back from shop--check engine light still on". What I'm curious about is the real function of this light ; ie. fuel system, pollution controls, engine management, etc. The word from the dealer was "we couldn't find anything", which could mean "we didn't look", or "the light really doesn't mean very much", or worse, "gremlins that used to be alllergic to diesel cars have now taken control of your diesel".
I wonder if today's reliance on computers and codes has put old-fashioned trouleshooting and diagnosis on the back burner.
It would be less of an issue if my dealer was in the neighborhood, but alas he's in Dallas, which when you add in the appointment scheduling, loan cars, trips back and forth, time off from working, etc., makes a reply such as " we couldn't find anything " annoying.
Steve

LightMan · #4 07-31-2002, 09:01 PM

Steve I have a '99 E 300 as well. My check engine light came on about 5k ago, and the mass airflow sensor went bad. Have the computer hooked up at the dealer and have the values checked out for the MAF. Usually the check engine light is related to emissions, check that out if its not the maf.

mbdoc · #5 08-01-2002, 08:09 AM

99 out of 100 times the check engine on these engines are emission related. However even the pe-glow system is monitored.
Some emission problems can shut the turbo off & even put the transmission into limp mode. Anyone with an OBD2 scanner SHOULD be able to retrieve codes from the system.

#6 08-01-2002, 10:39 AM

thanks for your replies. Here's an update un the Check Engine
light.
Notes from Tech: Ck codes found P0180 fuel temp sensor...
reading glitch between 41 and 43 deg C
reading blanks above and below these temps
Need new fuel shut-off valve(temp sensor inte
gral to valve.
The tests performed were:
Electric test program, fuel injection
Electrical system , test

All is well with the car now. M.B.D.O.C. yes the turbo was not operating when the check engine light was on. Even so, the car ran amazingly well!
Thanks again,
Steve

blackmercedes · #7 08-01-2002, 09:56 PM

Our 1998 E300 has definitely not been as reliable as our 1998 C230. Within 58,000 kilometers (about 40K-miles) we've replaced:

MAS

Glow plugs

Front crank seal

Rear crank seal

Final drive seals (all three)

ACC blower motor

Steering rack

Front lower ball joints

Steering damper

Belt tensioner & shock

Had the car been out of warranty, these repairs would have been THOUSANDS and THOUSANDS of dollars. Before the warranty on this car is up, it will be sold.

richunters · #8 12-03-2003, 12:01 PM

I got this Check engine code P0180, and a member directed me to this thread. Looks like my problem is same as Steve Hutson's, need to replace the fuel shutoff valve.

M.B.Doc, your comment that many codes are emission related prompted me to ask this question. I just had the catalytic converter replaced one day before the light came on. Could that have something to do with the error code?

mbdoc · #9 12-03-2003, 12:51 PM

P0 180 is the code for a defective fuel temp sensor.
Part of the fuel shut-off solenoid at the front of the fuel injection pump. MB number 000-078-44-49 (021-997-75-48 O-ring as well)
About $160.00 list for parts

richunters · #10 12-03-2003, 01:14 PM

Thanks MBDoc. Are ther any tricks I need to know to replace this part or is this not a do it yourself project for a beginner?

stevebfl · #11 12-04-2003, 08:26 AM

We recently had this code on one of our oldest customers cars.

During testing everything checked out. In reading the freeze frame info on the code the temp of the fuel was over 40deg C at the time of fault, BUT the engine temp was something like 18 deg C. From all the other values it was apparent that the event happened on a heat soaked engine. One who had been driven hard then sat 20minutes then was restarted. This was confirmed by the customer on two events.

We would have replaced the engine temp sensor, but he was a thousand miles from the end of his starmark warrantee, so we informed him of the remote possibility that this also could be a control unit problem. He has a good relationship with a distant MB dealer and he took it there and they replace both sensors and the controller.

The reason I point this out is that I am relatively certain that the real problem was the engine temp sensor. The normal range of accepted fuel temps ends at 40degC I think, but it is entirely possible and very likely that in climates like Floridas that a hot soaking motor will heat the fuel that hot. I would presume an engine temp similarly situated would excuse it. it our case the fuel temp and intake air temp planely showed the heated compartment and the engine temp was lower than it had been since last winter. Just a thought.

92497pmu · #12 10-15-2004, 10:07 AM

P0 180 is the code for a defective fuel temp sensor.
Part of the fuel shut-off solenoid at the front of the fuel injection pump. MB number 000-078-44-49 (021-997-75-48 O-ring as well)
About $160.00 list for parts

Quote:

Originally Posted by richunters

Thanks MBDoc. Are ther any tricks I need to know to replace this part or is this not a do it yourself project for a beginner?

RH-

I just got this same P0180 code on my 98 e300TD.
No shutoffs, shutdowns- car runs fine- but CEL is on, then off, then on again

This old thread ended abruptly...Did you replace this yourself, or off to the dealer?? Was it complicated or not too bad?

Help appreciated, thanks

92497pmu · #13 10-18-2004, 12:28 PM

Reply to myself...

now the @#$%@% CEL is off again. WTF?
Has anybody else had on again/ off again problems with the P0180 code?
Help sincerely appreciated

richunters · #14 11-26-2004, 01:20 PM

yes, mine was on then off then on again until I replaced the defective sensor. Now the mileage is better

activ123 · #15 03-06-2006, 12:31 AM

I bought a 1999 E300TD in december with a little over 100K miles. Great car - my truck was killing me in fuel.

I have changed the oil, fuel, cabin filters etc and this site was absolutely fantastic with all the help.

The car has a couple issues that popped up just now. One is the Check Engine Light is on. I had the nice folks at Autozone scan it for me and it is error code P0180 - Engine Fuel Temperature Sensor A Malfunction. I see in this thread that the sensor is part of the fuel shut-off solenoid at the front of the fuel injection pump. I think I found the MB part number 000-078-44-49 (021-997-75-48 O-ring as well)

Question is where is this thing!?!? I am new to this car and do not know my way around. I know where the fuel filter is though (replaced that right off) My guess is that the part is no good but maybe it's just a loose connector...

Also this appears to be a dealer only part - does any one know where I can get this part w/o the arm and leg the dealer will want?

Somewhere I read that the computer will deactivate the turbo on this car for some/all? CEL error codes - is this true? How would you tell?

Thanx in advance for any information you can provide.

Andy