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Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 8767
Experience:  I am ASE Master Truck Certified.
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The power came back after going in a pot hole but shortly after

Customer Question

The power came back after going in a pot hole but shortly after Loss of power again like it's in limp mode . Intermittent electrical something help
you
Submitted: 2 years ago.
Category: Medium and Heavy Trucks
Expert:  Cat Man replied 2 years ago.
Hi. Thanks for asking your question and requesting me! I will try and help you out.
Does the yellow check engine light come on when this low power happens?
Or no engine lights at all, just lo power?
Customer: replied 2 years ago.
Yes it comes on when it happens and goes off when it's fine
Expert:  Cat Man replied 2 years ago.
I see. Thanks for the information.
There are many things that can cause the light to come on and cause the engine to lose power. The most common is an injection actuation pressure system problem. I see this all the time. This is the high pressure oil system that activates the injectors.
To confirm you would need to have the ECM read for codes. The most often items that cause injection actuation pressure problems are a faulty Heui pump, faulty control valve on the heui pump, or a faulty injection actuation pressure sensor.
But it's best to have the ECM read to verify what codes it has.
Please reply back if you need more help or have more questions. I am happy to assist.
Customer: replied 2 years ago.
It sucks my scanner won't link to it do I need a diesel scanner
Expert:  Cat Man replied 2 years ago.
Yes most likely. Not all scanners will communicate with the 3126 engine. Sorry.
You could try gong to a dealer and having the codes read.
Most GMC's trucks do not have cruise control switches. If they do, you can use the cruise control switched to pull the flash codes.
Does your have cruise control switches?
Customer: replied 2 years ago.
No cruise control on this beast
Expert:  Cat Man replied 2 years ago.
Yeah that's what I thought. Sorry. The only way to verify is to have the codes read.
90% of the time its an injection actuation pressure system fault though. I see this all the time.
Let me know if you need more help.
Customer: replied 2 years ago.
Thank u I'm on the island of kauai if I'm able to find a scanner and it's not that can u still help me? I'm gonna change that thing and see what happens I'm a Porsche technician I took auto and diesel technology at UTI what scan tool should I get if I want to dabble more on the heavy side
Expert:  Cat Man replied 2 years ago.
You are very welcome. I am happy to help.
I would look into a Prolink. Other than getting Cat ET software Prolink makes a good tool.
Please reply back if you need more help or have more questions. I am happy to assist.
Expert:  Cat Man replied 2 years ago.
Hey,
I just wanted to see how things were going. Please let me know if you need more help. I am happy to assist. If my information was helpful, please leave a good or higher rating so that I receive credit. Thanks!

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