P0101 bluetec MAP sensors
 

2009 e320 bluetec
p0101 code cleaned maf sensors. Code returned immediately. Cleaned map sensor in manifold and code when away for a year.
code has returned, cleaning no go. Replaced map sensor and code still there. Did live data and looks like the turbo boost from MAP sensor and MAF sensors are responding to accelerating. The atmospheric pressure seems to be stuck on 29 inch. No movement to speed and acceleration. Is the map sensor in the air box the likely problem?
dave
No noticeable engine problem with with the code. Any problem with taking the car on a 1000 mile trip? Part may not arrive on time.
any diagnostic on the sensor?

I wouldn't!

The right front of the engine on the Manifold sensor A0061531528 replaced with Bosch 0261230193. Still had CEL and P0101 code. The old one test bench tested at 1.5V sensor with 4.6V applied?

Then i clean the left airbox sensor. Still CEL and same code.
I tested the new (Bosch 0261230189 green color print) and old sensor on the air filter box (green color print A0051535028) at atm 3.52V with 4.6V power source. They were essential within my experimental error for vacuum measurement to voltage. I replaced the old one with the new one. Erase the old code. It was showing the live scan data for the pressures and there was no noticeable difference in barometric pressure. I stop the car and removed the scanner. Test the car on the highway. No code. Put back on the scanner and no live scan of any air pressures were accessible. No code, No CEL. Guess all good and bench testing was not sensitive enough to tell a good part from a bad one.

Hope this help someone.

Scanner old Autel MS509.

The lesson here is that "bench testing of sensors" is a waste of time and money and went out in the 70's. Buy a factory or equal scanner and MB parts.

I spoke too soon. Code came back and so did live scan of pressures. Map showing 32 at on with engine not running and 0 with engine running. Reset and with g/sec increasing with rpm. Then code returned.

How to test if bad connections ($30), bad computer ($?), or bad MAF sensors ($400)?

Have maf sensor reading and wiggle the connectors?

Mass Airflow Problem
 

I am helping a friend replace the oil cooler seals in a 2010 ML350 Bluetec. After that fun little project, we’re not getting proper boost.

One interesting indicator is is that we are getting a constant air flow reading at 359g/s, regardless of the rpm or throttle position. Our identical reference car reads closer to 35g/s and changes with throttle and engine speed.

We switched air flow sensors (intake elbow) with another car and found that the sensor is good.

I’m concerned that we have a grounded wire somewhere. Is there something else that could cause a constant and high air flow reading?

More troubleshooting. After checking all the hose were connected properly (okay) and smoke tested (no leaks), there's a new code of too lean fuel.
As I recall the oil on the hose was there just before the turbo replacement 4 years ago.
I was thinking that the IND when replacing the turbo adjusted the turbo to get the proper boost with the leak and 3-4 years later the tear spread and was too much for the computer to compensate.
Now with the replacement hose, it's too air and causing a lean condition.

Is this likely? How to confirm the diagnosis? How to reset it to factory for computer to start with a condition what will not through a code and limp mode?
My scan resets the code but not the computer. Disconnect the battery?

If I do buy a computer scanner, who to set the fuel condition
Dave 2009 e320 bluetec (no urea system but with dpf).

Smoked the engine and only leak is at the oil separator.
cleared codes. Still have p0101. New code of oxygen sensor bank 1 sensor 1. Limp mode if off, lean is off. Live scan has both oxygen sensors 1 and 2 with 0.8 v at idle. Push accelerator and goes up to 1.2 v. Take foot off the accelerator and goes momentary to 0.6v. Seem to be as if cat is not working and running rich. Both sensors are about 3 years old. Last sensors heating elements didn’t work. Bad sensor again?
Both oxygen sensors are AFR sensors, $$$.
any source for a low cost alternatives?

Do you have access to Xentry? Can you redo adaptions? Without it, I Don't think the issue will ever truly go away.

I have the same code on my 2008 R320, has not given me too much perceived issues ---- but I did try and replace the entire mass airflow /air box assembly as the individual sensors were no longer available

Had a independent Mercedes diesel mechanic take a look as well. He did not have any particular good ideas. I will mention I do not think I have that oxygen sensor code

My new thought is that the blow-by is sufficiently high enough to place the predicted mask airflow (across sensors) out of specification for given engine operating condition, PCV dump just prior to turbo inlet--- ie after the twin MAF. (what is that sensor at the end of that PCV hose?). I am going to guess somewhere near the idle that the blow-by is too high - but have no actual idea. I will be re-routing the PCV to a puke can for this reason - and to reduce intake coking.

It doesn't throw it into limp, so I'm about done trying to fix it.

Back into limp mode
 

The AFR sensor (wide band oxygen sensor) code was P2A00 O2 sensor circuit Range/Performance Bank 1 Sensor 1.
I ran okay until 10 miles out of town and went into limp mode. Accelerator would cause high RPM without power. Transmission partially disengaging?
The MAF sensor give higher reading with more RPM and so the MAP readings seem to be lower reading when in limp mode. 35 in Hg instead of 40's Hg when accelerator pedal is down.

The engine blow-by pipe also has a sensor on it. I didn't check to see how much pressure or mist is coming from there. A catch can would be helpful.
I think a small diameter tube from the intercooler back into the engine oil would even be better. No emptying the can (as long is not much water condensate to go back into the engine). One would need to be custom made for there no plug in the area to tap into.

Both AFR sensors (upstream and down stream) gave about the same reading 0.92 V at idle, 1.1V with pedal down, 0.8 letting off the pedal. The Voltage on the AFR goes opposition of the regular oxygen sensor.

I heard that the MAF and MAP sensors rarely fail, Just need cleaning. As for the amount of pressure from the blow by, just disconnect the hose and see the amount of flow. I should clean that sensor too.

Is there a good source for an off brand AFR sensor? I don't want to spend that much if I am throwing parts at the problem.
One youtube has a guy replacing the O2 sensors for $25 each in a 2001 Mercedes V12. Likely a regular O2 sensor instead of AFR sensor.

I don't drive the bluetec much and that may be the cause of failing AFR sensor ($150 each) or just a bad batch from the 2008-2009.

Dave.

I would suggest buying a star tool to correctly interpret the codes being set by the vehicle, then working to a resolution. If you try to solve via generic P codes, you're pissing in the wind and will undoubtedly waste money.

Brough it into a shop that specializes in Euro cars with an Autologic scanner, codes 2633-001 and 2520-001, 2553-001 current codes. Replaced Upstream O2 sensor, pressure sensors on manifold and air box. Stopped giving O2 sensor code but still with MAF sensor.
Mechanics said that MAF sensor should also be replaced exhaust pressure sensor just did to no avail and MAF sensors ($$$). Replaced Exhaust Pressure sensor next to turbo. The same code MAF plus O2 code this time on my old scanner.

Can the computer be remapped without a doggle left on the OBD port? Latest mechanics said the computers can not be reprogrammed unless a doggle is left on the OBD port (electrical connector). That doesn't seem right to me.
I don't want to keep throwing parts at the problem.

Dave

Any updates? Thx

I dug the car out of the snow. Yo test, the pvc hose was disconnected and connection inlet plugged. Problem still there.
It looks as if the MAF sensors 8” upstream will need to be replaced. I was pricing them out before the snow started at $400. The local shops just want to through parts at it, hoping it’s not the computer.

Disconnected the pvc hose and plugged the T. Problem still the same.
car parked for 2 months in snow bank, battery low and recharged for two days and restarted on first crank. Check engine light still on. Re connected pvc hose. Check engine light still on.

Just replace the Y-clear air tube with 2 sensors and the crankcase ventilation assemble. MIL off but pending code and in limp mode.
Fuel rail pressure only going up to 10,000 psi instead of 20,000 psi.

Next replace fuel filter and check around ERF and intercooler hose area if wire was knock loose.
The Mercedes Sprinter codes are the one to use. Indicates the fuel is being limited -- check MAF, ERG, Leaks and Fuel problem.

Hello , Did you ever get this problem resolved?
please I’m having the same problem 2009 r320.
And if you did, can you please share what was the fix
thank you

The AEM warranty should cover it.

P0101
 

Basically you take the car to the dealer and they will modify the emissions system for free then warranty the parts for 10 years 120k miles or 4 years 48k miles if it’s a high mileage vehicle.
however since you have a 2009 it’s not part of the emissions recall & isn’t eligible so your outta luck.

I’m pretty sure 2009 R320 Bluetec is covered by the settlement. But here in Canada we’re still waiting for conclusion on the Bluetec Settlement.
In the main time I will like to get read of the p0101 code.
any help is much appreciated

The R320 is but not the E320.
Canada I have no clue about as I live in America.