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Buddy
Buddy, Technician
Category: Heavy Equipment
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Experience:  25 years experience
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ECU code 128 on a 04 Freightliner.

Customer Question

ECU code 128 on a 04 Freightliner.
Submitted: 8 years ago.
Category: Heavy Equipment
Expert:  Buddy replied 8 years ago.

HiCustomer Welcome to JA. I am Buddy, and i will try and help. There should be some more numbers along with that code. 128 just means that is a engine code. Try using you button on your dash display and see if you can get more numbers. Let me know.

 

Thanks

Buddy

Customer: replied 8 years ago.
34
Expert:  Buddy replied 8 years ago.

Thanks for info. What is last 6 of your truck vin#. Also does it have egr on it also.

 

Thanks

Buddy

Customer: replied 8 years ago.

M51328

yes for the egr

Expert:  Buddy replied 8 years ago.
Thanks for the information.Flash Code 34 indicates that the engine Turbo Boost Sensor input to the ECM has dropped below 5% (normally < 0.25 volts) of the sensor supply voltage. ?

This diagnostic condition is typically:?

  • Open sensor signal circuit
  • Open sensor +5 volt supply circuit
  • Sensor signal is shorted to sensor return circuit or to ground
  • Sensor +5 volt supply is shorted to the sensor return circuit or ground
  • Plugged or restricted air filter.

What sensors did you replace. Did you replace the turbo actuator or the wastegate?

 

 

Thanks

Buddy

Customer: replied 8 years ago.

Intake air sensor and barometric pressure sensor replaced -

part #23527829 and part #23527831, one was $46 and the other was $4.74 from Freightliner in San Antonio.

Do you think the turbo boost sensor might be the problem?

Thought the wastegate and the turbo actuator were the same...but the receipt from M&D Distributors in San Antonio called it an actuator, part #AIR757979-0002 ($157)

Expert:  Buddy replied 8 years ago.

The 23527829 is the turbo boost sensor. I would check wires at plug for bent pins or loose connections.If the turbo actuator is what you replaced. It would have to be calibrated, and you have to have detroit diagnostic link program on laptop to calibrate it.This has to be set very correctly to make turbo operate properly. Here is the procedures. Here <<<< click . They should of told you that when you bought the actuator. Our parts guys do. If you have anymore questions, just ask.

 

 

Thanks

Buddy

Expert:  Buddy replied 8 years ago.

Let me know if this is what you replaced.Also if you have anymore questions, just ask.

 

Thanks

Buddy

Customer: replied 8 years ago.

Kendall told me it was already pre-set. Can the actuator can be calibrated using a DDEC 4?

 

Are you in Texas?

 

If it's the turbo boost sensor and not the actuator, can I put my old actuator back on? Will it still need to be calibrated as well?

Expert:  Buddy replied 8 years ago.

Sorry for long delay, i am at work.If it is a ddec4, the turbo has to be replaced. If it is a ddec5 the actuator is adjustable. They are not pre set . They have to be set to your turbo. Each turbo is different. I am in Arkansas. You can put your old one on, and it should be pretty close, but it sounds like your original problem was the actuator. I would recommend going to freightliner and have them calibrate the new actuator to your turbo.If you have anymore questions, just ask.

 

 

Thanks

Buddy

Buddy and other Heavy Equipment Specialists are ready to help you
Customer: replied 8 years ago.
Air filter was pulled out and cleaned (we work in the rock hole...sand and gravel). Power has been restored but still get a rush of air every now and then, almost sounds like it's out of time, like it chugs every now and then, about a mile on down the road. Like it wants to backfire but catches. Timing for the actuator?
Expert:  Buddy replied 8 years ago.

Thanks for the accept. No need to accept again. Thats what it sounds like to me. Could be vpod onside of block between oil filters and flywheel housing. But i would start with timing of turbo actuator.Timing of the actuator is very cruscial, i think i spelled that right, lol. If it is turning to many rpm's it will derate and try to protect itself, like the symtoms you are describing. Hope this helps you out some.If you have anymore questions, just ask

 

 

Thanks

Buddy

Customer: replied 8 years ago.
Will running it out of time burn up the turbo? Truck will run 80mph down the road now whereas before taking out the air filter it would only get about 45mph. But seems like it has a miss in it now, like it is sucking air. It sounds like I shouldn't run the truck without getting the actuator calibrated? The SA Freightliner is about 45 miles from here; Austin Freightliner is about 50. Is that too far to run it without having that calibrated?
Expert:  Buddy replied 8 years ago.

You may just be hearing the vanes in the turbo, they normally sound like a vacuum cleaner when they kick in, and may be louder with air filter out. This could tear turbo up, being out of calibration. If you do drive it, i would take it easy and not try and put a load on it.If you have anymore questions, just ask.

 

 

Thanks

Buddy

Customer: replied 8 years ago.
The error code has gone away now; check engine light went off after rechecking the new sensors and taking out the air filter. Thanks for your help. It looks like my only alternative is to go to Freightliner to calibrate the actuator and buy a new air filter. I am concerned that the turbo is getting too hot.
Expert:  Buddy replied 8 years ago.

If you didnt turn the adjuster on the original actuator, you should be able to put it on and be very close with no problems..Glad to hear it was just air filter.One other thing you might could do if you wanna drive it with that one and possibly be safe is to remove the air line from the actuator and plug the line off, this way turbo vanes will not be kicking in.If you have anymore questions just ask.

 

Thanks

Buddy