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Eric
Eric, Automotive Repair Shop Manager
Category: Chevy
Satisfied Customers: 32539
Experience:  20+ yrs. experience as repair shop manager and technician.
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I have a 2005 Chevy C5500 42' Bus with a Duramax 6.6 LLY

Customer Question

Hello, I have a 2005 Chevy C5500 42' Bus with a Duramax 6.6 LLY Engine 280,000 Miles . I am getting a P0193 Code Which states it is a power Enrichment problem. I Recently changed all my fuel lines and being Gm no longer has the fuel lines i ran Aromotive steel breaded lines and fitting not sure if this could cause the issue however it did run just fine for a few weeks after the change So i do not think this affected it but ?? . To try and solve the issues i have replaced the fuel filter and filter housing .i bleed the system, changed the Fuel pressure Sensor and harness as well as the Fuel Relief valve . The Vehicle drives fine until you try put the peddle to WOT and then it goes into limp mode and will not go over 40mph or rev past 2000 rpm. i am really hoping someone can help me with this issue!
Submitted: 1 year ago.
Category: Chevy
Customer: replied 1 year ago.
I am leaning twords the Injection Pump ( Cp3 ) being it has so many miles .
Expert:  Eric replied 1 year ago.

HI,

DTC P0193 CIRCUIT DESCRIPTION The engine control module (ECM) monitors the fuel rail pressure (FRP) via a FRP sensor. When the FRP is high, the signal voltage is high. When the FRP is low, the signal voltage is low. If the fuel rail pressure is above the upper limit for the sensor, DTC P0193 will set.

This is an electronic fault due to either faulty FRP sensor, wiring or ecm, not an actual fuel pressure issue. Since you have replaced both the FRP sensor and wiring harness for it, then unless there is a bent pin at the ecm, the problem is the ecm itself and it will need to be replaced and programmed.

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Customer: replied 1 year ago.
Thank you . So this cannot be an issue with the Injector Pump or fuel pressure regulator? Or possibly injectors? It also could be a bad wire possibly for the ecm is what you are staying as well?
Expert:  Eric replied 1 year ago.

HI,

Correct, it wont be the injector pump or regulator or injectors. Possible causes are FRP sensor, wiring harness between the ECM and FRP sensor, or the ECM. You stated that you replaced the FRP and the wiring harness, so this just leaves the ECM as the culprit, unless the harness you replaced was NOT the one between the FRP and the ECM. Then there is still a possible wiring issue with short or open in it.

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Customer: replied 1 year ago.
OK that's very good to know. The truck runs just fine until you try to mash the gas then it get the Enrichment code and goes Into limp mode. I baught this bus used amd have no idea of the pump and or injectors a have been replaced. There is no smoke put the tail pipe at all and it runs super clean and smooth but once it goes I to limo mode it's done for.Os there a possible ot still has stock Cp3 Pump and injectors at 280,000 Miles? Also I only replaced the Pigtail to the Frp not the complete Harness.
Expert:  Eric replied 1 year ago.

HI,

I would be surprised if the pump and injectors are original at that mileage, but with no smoke, running clean and no fuel in the oil, I would leave well enough alone on them at this point as they are doing their job.

Usually if it is a wiring issue, it will be a break in the wiring within about 12" of the FRP sensor connector, but go ahead and check it all the way to the ecm. If good, replace the ECM

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Customer: replied 1 year ago.
deffinetly runs very clean. No fuel in oil. Starts right up and It ran just fine when I baught it a few weeks ago. Mashed the gas on test drive got it up to 80mph no problem drive it home 150 miles . The problem just started a few days ago. I'm assuming you have Seen this quite a bit on these? And yes your right they have had to be changed at some point. But yes I'll leave well enough alone I suppose. I was about to take out the pump so I have ot torn down . Do you think it would be a good idea to change the Fp regulator since I have it as well to replace? I hear they go out and cause a surging idle. Unless of course the one on the cp3 is newer one rebuild pump they may have replaced. Do you see the ecm's go a lot in theses?
Expert:  Eric replied 1 year ago.

HI,

If you already have the regulator and are at it, it wouldnt hurt to go ahead and replace it.

Yes, I see quite a few ECMs fail on these 6.6 engines on the FRP circuit.

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Customer: replied 1 year ago.
Great . This is all very refreshing to know . I really appreciate your advise. I will check the wires and take it from there. If it's the ecm that's bad do I have to have it take the vehicle to the dealership to Program the computer or do they do that with my Vin # ***** I just simply plug and play? Also the ecm is located right under the hood on Pass side correct?
Expert:  Eric replied 1 year ago.

Hi,

Sorry for the delay, my internet modem is acting wonky today and losing signal every few minutes

If it is the ECM, as long as you provide the vin and mileage, the supplier can preprogram it so that it is a plug and play. Correct, under the hood on the passenger side.

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Customer: replied 1 year ago.
No worries. OK great! I'm going to check wires first. Is there a procedure I can check for continuity and ground off the pins at the Pigtail with a volt meter ?
Expert:  Eric replied 1 year ago.

HI,

Disconnect the connector at the FRP and at the ECM and check continuity between the wires at each end. Let me check to see if I have the connector pinout for the ECM

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Customer: replied 1 year ago.
OK. Great. Any particular setting on the Volt meter?
Expert:  Eric replied 1 year ago.

HI,

Just set at ohms to read resistance. If resistance is missing or reading infinity between the two ends of the wiring, there is a break

Ok, if my diagram for connector pinout is right, it should be Connector 2 on the ECM, pin 42, yellow wire. See attached

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Customer: replied 1 year ago.
Thank you very much for the diagram. How do I know which is #2 connector? Is it labeled? Or colored?
Expert:  Eric replied 1 year ago.

Hi.

It will be the middle connector. There should be 3 and the C2 is the middle one and is also a bit longer than the other 2 as it is a 72 pin connector and the other 2 are 56 pin connectors

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Customer: replied 1 year ago.
Great thanks again. Excited to see what's going on. And very glad I didn't change pump. Big job and expensive as well . Whould I expect to pay around $800-1000 for computer if needed?
Expert:  Eric replied 1 year ago.

Hi,

You are welcome. Look around online and you usually can get a remanufactured one for around $400-$450. I use

www.aesmodules.com/ or https://www.cardone.com/products/electronics/electronics-products-remanufactured/engine-control-modules-prom-chips for reman ecm and have good luck with them. Havent gotten a bad one yet from either.

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Customer: replied 1 year ago.
Fantastic! Thanks again!
Expert:  Eric replied 1 year ago.

HI,

You are welcome and have a great week!

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Customer: replied 1 year ago.
You as as well!!
Expert:  Eric replied 1 year ago.

Hi,

thanks!

Customer: replied 1 year ago.
Good Afternoon,I just finished testing the wire to the 42 pin and to the connectors which is the middle pin in the three pin. There is definitely no break in the wiring. Is this for certain now the ecm that's is the culprit? Pretty much 100%
Expert:  Eric replied 1 year ago.

Hi,

Yes, this means it is the ECM with wiring checked out as good and the FRP sensor being new.

Customer: replied 1 year ago.
OK great. I ordered it. It was $750. Does that sound right from your source? Programed and all
Expert:  Eric replied 1 year ago.

HI,

A little bit high, but within reason. I checked and my cost as a repair shop for yours is $600, so $750 retail would be about right

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Customer: replied 1 year ago.
Thank you for checking. It's much better then the $1100 Gm dealer wanted so I'm grateful for the source. I'm really hoping this does the trick. Being there really isn't anything else it can be . I'll have it thursday and let you know as soon as I install .
Expert:  Eric replied 1 year ago.

HI,

Sounds good!

Customer: replied 1 year ago.
Oh Boy . I was scanning over this morning and i noticed at the start of the question i had Put P0193 fuel pressure low while Power Enrichment ! However it should of read P1093! Wow !! I made a terrible mistake! And this is a completely different problem not related to the Ecm i believe. I hope i can cancel my Ecm order !!! Can you please advise me on what this means and what My issues may be with this code . this is why i was leaning tword the Cp3 or FPR. i am really upset with myself at the moment . I made a bad typo and confused myself and lead you to the wrong code and diagnosis. I am terribly sorry
Expert:  Eric replied 1 year ago.

HI,

Dont beat yourself up. Mistakes happen. Call them this morning to cancel the order, it should not have shipped yet.

Ok, P1093 is 95% of the time the injection pump AND the regulator as well. Usually due to a failing regulator which then causes the pump to start to fail.

Customer: replied 1 year ago.
Thank you very much for the Reply this morning. I am going to call them right now and cancel the order. They had told me they build these from scratch. And the order is not refundable. So hopfully there isn't to much of an issue.
Expert:  Eric replied 1 year ago.

HI,

Explain what happened and if you need to, talk to one of their managers.

Expert:  Eric replied 1 year ago.

I noticed we have not yet resolved your concern you asked about. I would sure appreciate it if you would reply so I can offer my skills and knowledge and repair guide access to help as best I can.

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If the answer is YES to any of these just press reply and lets work on this concern some more.

If you have new questions now or in the future please do not hesitate to ask them. If you would like me to assist you. Just bookmark this page so you can access my profile easy and post a new question from the question box on my profile page.

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Customer: replied 1 year ago.
Hello comma I actually was able to thank goodness get the module refunded. And I was able to buy and injection pump. I just tore down the incomplete engine to get the injection pump out. I've done so and I'm waiting tomorrow to actually put it back together. That is one heck of a job. I will let you know as soon as I'm finished and have it buttoned up. I've also decided to change many other components as well like the water pump a crossover pipe and a few other things since I was in there. I will let you know soon as I'm finished
Expert:  Eric replied 1 year ago.

HI,

Ok, sounds good

Expert:  Eric replied 1 year ago.

I noticed we have not yet resolved your concern you asked about. I would sure appreciate it if you would reply so I can offer my skills and knowledge and repair guide access to help as best I can.

~Do you still need more help?
~Confused by my info request or answer?
~Need more time?
~Confused on how the site works?
~Need more detail or a different explanation?

If the answer is YES to any of these just press reply and lets work on this concern some more.

If you have new questions now or in the future please do not hesitate to ask them. If you would like me to assist you. Just bookmark this page so you can access my profile easy and post a new question from the question box on my profile page.

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Expert:  Eric replied 1 year ago.

If you have any other questions on this, feel free to ask for more help by clicking the REPLY TO EXPERT button, otherwise please click the OK SERVICE, GOOD SERVICE OR EXCELLENT SERVICE to pay for services rendered per your customer agreement as this is a PAYSITE and experts are not paid for their time, services, or knowledge until you do so.Thank you.

Customer: replied 1 year ago.
Good Evening, I just buttoned up the truck n took it for a ride. It deffinetly ran much better. I was delayed by parts ect but deffinetly a big job. I unfortunately have a p0455 code for Boost control solenoid now. I checked all my connection ect n pig tail to Solinoid. I also tried to unplug it and then got a circuit Hugh boost Solinoid as well. Do you know what would cause this?
Expert:  Eric replied 1 year ago.

HI,

Admittedly that is not an area I really specialize in and would suggest opening a new question for that. I can only say if this code was not present before the work, then it will be related and I would check carefully for any crimped wiring or wiring loose in the connector

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Expert:  Eric replied 1 year ago.

Please remember to rate service using the rating page so that I may receive credit. Thanks