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Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 8954
Experience:  I am ASE Master Truck Certified.
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I have a Cat 3126 on a frieghtliner chasis. I am a 2003 39P

Customer Question

I have a Cat 3126 on a frieghtliner chasis. I am a 2003 39P model RV. Last night when drivign the check engine light came on with fault code 39. I changed the sensor and now have fault 15 and 39. Please advise
JA: What is the complete model and serial number of your machine?
Customer: 3126B is the model and serial number is *****
JA: Anything else you want the equipment mechanic to know before I connect you?
Customer: I did put the new sensor on thats all I have done
Submitted: 1 month ago.
Category: Medium and Heavy Trucks
Expert:  Cat Man replied 1 month ago.
Thanks for asking your question. I will try and help you out.Code 164-11 (39) is defined as an Injection Actuation Pressure System fault. I see this a lot on these engines. This code indicates the ECM is not seeing the correct Injection Actuation Pressure.
Code 164-2 (15) is defined as injection actuation pressure is erratic.
These codes can be caused by several things.The first and most common is a faulty Injection Actuation Pressure Control Valve. Also known as an IAPCV. It has two wires connected to it and is screwed into the High pressure HEUI pump.
Second is a Faulty HEUI pump. To test a high pressure 5000 psi gauge is needed to connect to the outlet of the HEUI pump.
Third is a faulty IAP sensor
And lastly is a leaking injector.Please reply back if you need more help or have more questions. I am happy to assist.
Expert:  Cat Man replied 1 month 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.