Medium and Heavy Trucks

Have truck repair questions? Ask an Expert

Connect one-on-one with {0} who will answer your question

This answer was rated:

2000 c10 in a freightliner fld120. Pulled ecm, bench tested…

2000 c10 in a freightliner...
2000 c10 in a freightliner fld120. Pulled ecm, bench tested at a caterpillar shop, ecm tested good. Reinstalled ecm in truck, still will not start.
Have 12v going into pin 70, verified multiple times in multiple ways. Already checked the grounds in the ecm plug and throughout the truck and engine. Replaced the fuel filter assembly to an updated assembly and new filter. 3 new batteries.
Now, with all that said, the truck will not start. I hooked a scanner up to the obd port, only shows one module and one code, abs sensor. When you crank the motor, it rolls over fine, will fire with a little ether but only with ether. Have cranked long enough to show oil pressure.
Cat shop showed me the only ecm code was fuel temp sensor out of range. Whole cranking there engine, I get no response from the Rach. I have no check engine or stop engine lights.
I can not understand how I can have a good ecm that is getting power, but the cat shop tells me it's the truck itself not getting power to the ecm. Yet, the freightliner shop tells me its the ecm and not the truck side but the engine not sending ecm info to the truck. I don't want to haul the damn thing to a shop because I feel that neither place knows any more than i do right now because each one is telling me a its the other guys fault to put it in a simple summary.
Show More
Show Less
Ask Your Own Medium and Heavy Trucks Question
Answered in 3 minutes by:
10/5/2017
Technician: Cat Man, Cat Engine Expert replied 4 years ago
Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 10,344
Experience: I am ASE Master Truck Certified.
Verified
Thanks for asking your question. I will try and help you out.
So when you turn the key to the on position, the yellow check engine light does not come on?
Ask Your Own Medium and Heavy Trucks Question
Customer reply replied 4 years ago
That is correct. The cat shop tells me it's because the ecm isn't getting power, i have verified it is getting power. The freightliner shop tells me its because the ecm is bad, the ecm tested good at cat on the bench
Technician: Cat Man, Cat Engine Expert replied 4 years ago
Thanks for the information.If the yellow check engine light does not come on when the key is turned to the on position and the engine will not start, there are only 2 things that can cause this.The first and most common is the engine ECM is not getting the correct power and ground to function. The ECM should have power on pins 52, 53, and 70 of the rear most ECM connector. This is the truck side harness connector. 70 is the key switch wire. The grounds are on pins 65 and 67. You can remove the connector and check for power on these pins. If you do not have power on these pins, you most likely have a blown fuse in the electrical system. I would check all fuses first. I also like to use the Cat Power bypass harness when I suspect a Power or ground issue.If you do have correct power and ground to the ECM, you most likely have a failed ECM. I have seen this many times over the years. To confirm the ECM is bad, you would need to install a known good ECM on the engine or you can take the ECM to the dealer to be tested. Unfortunately the ECM cannot be repaired. Replacement is the only option. I am sorry. I wish I had better news.
If the dealer can communicate with the ecm and read codes. Most often it means the ecm is good. However. The only true way to know if it’s the ecm is to install it on a known good running engine.Please reply back if you need more help or have more questions. I am happy to assist.
Ask Your Own Medium and Heavy Trucks Question
Customer reply replied 4 years ago
I figured I'd get the standard response. I have checked all the stated pins for power and ground. I already stated that. Altorfer cat verified the ecm is live and good. asked and answered. So I'm back to where I started not knowing
Technician: Cat Man, Cat Engine Expert replied 4 years ago
Have you load tested the power wires to the ecm?
Ask Your Own Medium and Heavy Trucks Question
Customer reply replied 4 years ago
Load tested? Pin 70 is the only one that has 12v, correct? The others are a lower voltage and I'll have to go back through my notes to find out myself. But pin 70 is 12v and I've gone so far as to remove that pin from the ecm plug and crimp a new gold pin on a wire to run into the ecm plug direct to the battery just to eliminate the possibility of a power problem.Is it possible that there's a sensor, like the cam timing sensor, that could be creating a fault in the self test and not allowing it to do whatever it needs to do and basically locking the ecm out?
Lousy way to explain a question but I'm frustrated with this
Technician: Cat Man, Cat Engine Expert replied 4 years ago
Just because a wire shows 12 volts with a meter does not guarantee the wire can carry a load.
You need 12 volts on pins 52 and 53. 70 is the key switch wire that should have 12 volts.
Ask Your Own Medium and Heavy Trucks Question
Customer reply replied 4 years ago
I'm tracking with you in the load test now, I ran a separate line to avoid the possibility of the lounge not having enough capacity through corrosion and time to not carry the load.
The mechanic at cat told me that 70 was the only 12v power and the others were like 7(?) volt until it was actually running. Is that correct or did my dumb ass misunderstand?
Technician: Cat Man, Cat Engine Expert replied 4 years ago
He is dead wrong. The ecm needs at least 7.5 volts on each pin to function correctly. You needs that 12 volts on 52,53,70.
Ask Your Own Medium and Heavy Trucks Question
Customer reply replied 4 years ago
Ok, it's more likely that I heard wrong or wrote it down wrong. So if there's 12 volts on 52 and 53, where does the 2 pins get their power from? Are they switched on the key or do you know? In other words, can i tap into those 2 as well to power directly like I did pin 70?
Technician: Cat Man, Cat Engine Expert replied 4 years ago
Normally pins 52 and 53 are unswitched 12 volt power from the batteries with a fuse. Keyswitch 70 is from the ignition switch.
Ask Your Own Medium and Heavy Trucks Question
Customer reply replied 4 years ago
Ok. I will checkwhen I can get to it. Thank you
Technician: Cat Man, Cat Engine Expert replied 4 years ago
You are very welcome my friend. I am happy I could help.
Ask Your Own Medium and Heavy Trucks Question
Customer reply replied 4 years ago
I apologize if I came across snotty earlier, I checked my notes and those 2 pins were explained to me as low voltage, only I wrote being low voltage and not check for low voltage. That was the problem. Nearly corroded in two and was only getting 7 volts. Thank you for all your help and I will keep this open for now until I make a test drive to make sure there isn't any other issues
Technician: Cat Man, Cat Engine Expert replied 4 years ago
No problem at all my friend. I am happy to help. Please reply back if you need more help or have more questions. I am happy to assist.
Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 10,344
Experience: I am ASE Master Truck Certified.
Verified
Cat Man and 87 other Medium and Heavy Trucks Specialists are ready to help you
Ask your own question now
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a technicianLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask Cat Man Your Own Question
Cat Man
Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 10,344
10,344 Satisfied Customers
Experience: I am ASE Master Truck Certified.

Cat Man is online now

Related Medium and Heavy Trucks Questions
I have a 3126 cat. Code 164-11. I've replaced 6 pack
I have a 3126 cat. Code 164-11. I've replaced 6 pack injectors, oil pump, ipr, injection pressure sensor. Still no start. Spray a very little starting fluid. Start up good. Only. … read more
Daniel Wilson
Daniel Wilson
Auto Mechanics 1&2/diesel mech
6,062 satisfied customers
I have a 98 freightliner with c12. No power and code sid-84
I have a 98 freightliner with c12. No power and code sid-84 timing actuator #2. Changing fuel filters now. Any ideas what else to look for? … read more
Gary A.
Gary A.
Associates in Diesel Technology and Business Management
7 satisfied customers
Cat 3126 won't start cold unless plugged in for at least an
cat 3126 won't start cold unless plugged in for at least an hour or using ether. Runs and starts after the initial start … read more
Daniel Wilson
Daniel Wilson
Auto Mechanics 1&2/diesel mech
6,062 satisfied customers
1996 Freightliner FLD120 wiper wire diagram. Freightliner
i notice that the wiper motor not getting ground. after applying groung to the green wire the motor works. but can not find the fuse or breaker … read more
Andy
Andy
truck /coach technician
Vocational, Technical or Trade School
214 satisfied customers
Have a 1999 FLD120 with an ECM that needs to be replaced
have a 1999 FLD120 with an ECM that needs to be replaced have the ECM might need new wires that's my issue … read more
Nich1019
Nich1019
Diesel Technician
Vocational, Technical or Trade School
62 satisfied customers
I am reprogramming a replacement ecm for a caterpillar C10
hello. I am reprogramming a replacement ecm for a caterpillar C10 ECM … read more
catmastertech
catmastertech
Field service technician
Vocational, Technical or Trade Scho
1,325 satisfied customers
99 freightliner xl with cat 3406. Will crank and not start.
99 freightliner xl with cat 3406. Will crank and not start. If ether is sprayed into it, it will run until the ether is used up. Computer has been tested and is OK, fuel filters replaced, hand primer … read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,344 satisfied customers
1998 Freightliner 1FVXTECBXXHA02079 I'm actually changing
1998 Freightliner 1FVXTECBXXHA02079 I'm actually changing the motor from a C10 to a C12 I need a wiring schematic for caterpillar C12 engine. I also need the wiring schematics for a C10 I need the C12… read more
Daniel Wilson
Daniel Wilson
Auto Mechanics 1&2/diesel mech
6,062 satisfied customers
I have a 5EK 3406e that I cannot seem to get to run
Hello there, I have a 5EK 3406e that I cannot seem to get to run strongly, even after full out of frame overhaul … read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,344 satisfied customers
I have a Freightliner semi with a Caterpillar C15 engine and
I have a Freightliner semi with a Caterpillar C15 engine and some technical answers please. … read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,344 satisfied customers
I have a 96 Freightliner fld120 s60, that just cranks and
I have a 96 Freightliner fld120 s60, that just cranks and cranks but does not fire. I've replaced the fuel filter and topped both the filter and the davco with fresh fuel, with no luck. I can not get … read more
Andy
Andy
truck /coach technician
Vocational, Technical or Trade School
214 satisfied customers
Just put a cat motor in my classic and trying to find a
just put a cat motor in my classic and trying to find a diagram for the new wiring harness for the ecm … read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,344 satisfied customers
I have a c10 cat in a 2000 built. The engine wont start
I have a c10 cat in a 2000 peter built. The engine wont start unless we us starting fluid. after its started it runs great. during cranking we have about 35 psi fuel pressure. While cranking the motor… read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,344 satisfied customers
Think the motor is locked but im not sure if it could be
Think the motor is locked but im not sure if it could be something elsr … read more
Wayne
Wayne
Journeyman
Vocational, Technical or Trade Scho
5,115 satisfied customers
I put a 99 c10 in my 98 international that I put a rod of of
I put a 99 c10 in my 98 international that I put a rod of of side. Also a c10. The cam sensor and crank sensor on new motor are two wire, where my ecm wires are 3 wire. Sensors are in different places… read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,344 satisfied customers
How do you purge the air out fuel lines after changing fuel
How do you purge the air out fuel lines after changing fuel filter and drained water from canister on a freightliner fl70 catapiler 1997… read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,344 satisfied customers
97 Freightliner FLD120 Check engine light staying on and seems
97 Freightliner FLD120 Check engine light staying on and seems to be showing a code 2 blinks and 3 blinks.N14 cumming engine.… read more
Clayton
Clayton
Technician
Vocational, Technical or Trade Scho
627 satisfied customers
I have a 2004 Freightliner with a CAT C10 Engine in it. This
I have a 2004 Freightliner with a CAT C10 Engine in it. This truck fires right up in the morning, however a couple hours of running and the truck just shuts down when at idle. I have ran the codes in … read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,344 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

He answered my question promptly and gave me accurate, detailed information. If all of your experts are half as good, you have a great thing going here.

DianeDallas, TX

< Previous | Next >

Meet the Experts:

Daniel Wilson

Daniel Wilson

6,062 satisfied customers

Owner at DJ Wilson

Cat Man

Cat Man

Cat Engine Expert

10,344 satisfied customers

I am ASE Master Truck Certified.

Wayne

Wayne

Journeyman

5,115 satisfied customers

worked on, Gmc, Macks, Freight liner,Mercedes Benz,,Ford, sterling

Jeremy

Jeremy

Certified Truck/Bus Technician

2,756 satisfied customers

ASE Med/HD Truck Technician, NATEF Diesel Engines and Electrical/Electronics Technician, Network Engineer specializing in CAN faults, Aftertertreatment, and vehicle communications

Curtis B.

Curtis B.

Technician

1,947 satisfied customers

Technician turned service manager on multiple lines of trucks and engines, used in industry.

cumminsdr

cumminsdr

Mechanic

1,886 satisfied customers

All types of Cummins applications

Chris (aka-Moose)

Chris (aka-Moose)

Technician

641 satisfied customers

24 years of experience diagnosing & repairing

< Previous | Next >

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x