Engine recovery (check component B5/1)

[Iangiulu]

Hi, I have a problem with my MB w203 220cdi.

The drive is operating normally, but when the engine exceeds 3000 rpm, once released the accelerator enters the protection mode.

In diagnosis mercedes this is the error:

Check pressure transducer B5 / 1

I tried to read the error with a generic diagnostic and this is the result:

P0238 - Sensor boost (voltage too high).

I can not understand what the problem that causes this error. Can anyone help me?

 

[jaymanek]

You could try changing the boost pressure sensor but usually this indicates issues with the turbo... best to get it onto a star machine to do some tests.

Also have you checked intercooler pipe for splits?

 

[E270 Owner]

Check the alternator voltage is absolutely correct.

I chased this problem down after watching the voltages go all over the place on a live MB Star data session deviation wasn't no more or less +/- 4 volts over 12v.

At idle the voltage was 13.7v when revved it remained the same but when the vehicle was driven it revealed the problem.

P0237 Turbocharger Boost Sensor A Circuit Low
P0238 Turbocharger Boost Sensor A Circuit High


Mercedes told the customer the turbo & actuator was faulty
then
The MAP sensor
then
The Inter cooler/boost pipes/charge air system sensors and all pipe work.

He did not disclose how much he had spent with Mercedes.

A 200 amp Bosch unit fitted for 250 quid problem solved.

 

[Iangiulu]

Check the alternator voltage is absolutely correct.

I chased this problem down after watching the voltages go all over the place on a live MB Star data session deviation wasn't no more or less +/- 4 volts over 12v.

At idle the voltage was 13.7v when revved it remained the same but when the vehicle was driven it revealed the problem.

P0237 Turbocharger Boost Sensor A Circuit Low
P0238 Turbocharger Boost Sensor A Circuit High


Mercedes told the customer the turbo & actuator was faulty
then
The MAP sensor
then
The Inter cooler/boost pipes/charge air system sensors and all pipe work.

He did not disclose how much he had spent with Mercedes.

A 200 amp Bosch unit fitted for 250 quid problem solved.

OH MY GOD!!! They wanted to change a turbocharger pipe!

Please speak me what I have to check. It's okay if I check the voltage from the secret menu of cdb? I remember that the voltage is around 13.5 volts with engine on, but I have to check.

Now I show you a test with monitoring map, maf and engine rpm.

Yesterday I did some tests:

The maximum boost pressure is 255kPa (2.55bar)
Atmospheric pressure during the test: 97kPa (0.97 bar)
Subtracting is: 1.58 bar boost (peak)


Accelerazione @90 km/h: (nessun problema)


Acceleration @120 km/h: (no problem)


Acceleration @140 km/h:




I have highlighted the moment, wanting to resume the gas after it is closed, the car had no power.

And here is the log of the freeze:



I reset the error and I tried again the car after a few minutes he reappeared the problem:




Reading the error log known low-pressure turbocharger (124,75 kPa strangely the same in both cases) and a high load.
What could be causing the problem? I think the variable geometry works well.

 

[E270 Owner]

Firstly I have Proscan and never use it on Mercedes vehicles I use MB Star SDS

With Star you can use it to test the components with the actuation's menu thus test the turbo and electronic actuator position correctly.

I suggest you take it for a MB Star session on road test, and get the alternator voltage amp reading read correctly under load.











.

 

[Iangiulu]

Firstly I have Proscan and never use it on Mercedes vehicles I use MB Star SDS

With Star you can use it to test the components with the actuation's menu thus test the turbo and electronic actuator position correctly.

I suggest you take it for a MB Star session on road test, and get the alternator voltage amp reading read correctly under load.

.

I went to MB but they did a "short test", they look for the problem wanted yo TRY to replace a turbocharger pipe (this) but they weren't sure to solve the problem in this way.

Did you know what is the max boost pressure of the turbocharger? I thing 1.6 bar is an high value.

 

[E270 Owner]

I went to MB but they did a "short test", they look for the problem wanted yo TRY to replace a turbocharger pipe (this) but they weren't sure to solve the problem in this way.

Did you know what is the max boost pressure of the turbocharger? I thing 1.6 bar is an high value.

The component they wanted to replace has a rubber seal one end and a retaining clip the other, one fault that can occur with those is if someone uses the wrong bolt (too long) when replacing it after any work on it, the bolt goes through the housing making a hole in it.

I have only ever replaced seals on those units or replaced because of damage caused by the wrong bolt used refitting them or oil contamination inside the baffling material.

I strongly suggest you find a independent MB specialist that will take time with you looking into this problem with Star and not simply want to do a parts swapping exercise.

 

[Iangiulu]

The component they wanted to replace has a rubber seal one end and a retaining clip the other, one fault that can occur with those is if someone uses the wrong bolt (too long) when replacing it after any work on it, the bolt goes through the housing making a hole in it.

I have only ever replaced seals on those units or replaced because of damage caused by the wrong bolt used refitting them or oil contamination inside the baffling material.

I strongly suggest you find a independent MB specialist that will take time with you looking into this problem with Star and not simply want to do a parts swapping exercise.

Here in Italy only MB workshop have the stardiagnosis tool!
I don't understand what is the bolt your are speaking about.

Can you give me the number?

 

[E270 Owner]

Bolt 160 is shorter than bolt 120
if bolt 120 is used instead of 160
the unit becomes damaged internally.

Care must be taken if this unit is taken off and replaced again.

 

[Iangiulu]

Bolt 160 is shorter than bolt 120
if bolt 120 is used instead of 160
the unit becomes damaged internally.

Care must be taken if this unit is taken off and replaced again.

I look for the voltage when the car is in use.
The value is about 14.3 14.4 volt.

Is this good?

 

[E270 Owner]

You need MB Star to monitor voltage correctly not the dashboard volt meter.

You need MB Star to test the functionality of the components affected by P0237 P0238











.

 

[Benz270cdi]

Have you checked to see if the vanes are sticking in your turbo?

 

[Iangiulu]

Have you checked to see if the vanes are sticking in your turbo?

Are you speaking about the vanes of the variable geometry?
I have to verify if they move correctly when I have some time.

 

[Benz270cdi]

Yes , I would buy two bottles of forte diesel turbo cleaner and run a tank of the better quality diesel and see if your problem goes away