Service engine soon light

[Peewee21]

My ses light is normally off but yesterday it came on when i got up to 75mph so i let off the accelarator and it went back out any info would help. Thanks in advance

 

[WarWagon]

Pull the codes. Use a paperclip and take/post a video if you have trouble reading them out.

 

[Peewee21]

Which pins do you use

 

[WarWagon]

Post #7.
http://www.thetruckstop.us/forum/threads/6-5-diesel-technical-library.589/

 

[Peewee21]

I was able to pull code numbers 16 36 78 84 85 98 99

 

[NVW]

I would start by cleaning all the grounds: http://www.thetruckstop.us/forum/threads/grounds-what-are-they-where-are-they.17457/

Clear your codes, you can disconnect the batteries, or IIRC there is a way by depressing both the brake and accelerator pedal simultaneously to do it, the stickies or tech library may outline how.

See what comes back.

 

[Peewee21]

I've cleaned all the grounds and cleared the codes then drove it down the road and back about 3 miles and checked again and it didnt show any codes coming back up

 

[NVW]

The ground cleaning likely cured it.

 

[Peewee21]

I hope so

 

[THEFERMANATOR]

Code 78 is the one that caused your light to come on at 75. My BURB did the same thing when the boost solenoid went out. It wasn't constant, but something about that speed seems to trip the 78 when theres even the slightest boost issue.

 

[Peewee21]

Is it because of the waste gate

 

[THEFERMANATOR]

It can be MANY things cause the code 78. Vacuum pump, broken vacuum line, vacuum solenoid, boost pressure sensor, plugged air filter, rotted out exhaust crossover, turbo, wastegate actuator, plugged exhaust from a crushed pipe, or even an ECM could cause a code 78. Code 78 just means actual boost is not what the ECM is commanding it to be, so you have to diagnose it to see why it isn't.

 

[Peewee21]

Ok thank you for the info i will see whatbi can find