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1stLtDan
Active Member
USA
13 Posts |
 Posted - 11/10/2017 : 06:15:04 AM
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| Over the years of working with this code here's the best advice I can pass on to new techs: the 10 gauge red and white wires At The Battery Cables, fuses are cheap , change those out with known good fuses, inspect fuse holders, any signs of bad connections , cut those out solder and shrink wrap new holder back in.Now follow the red and white wires from the batteries along frame. You should find the weather connection plug next to transmission bellhousing. One of two things - disconnect and inspect- if signs of corrosion or discolored contacts cut out plug connection. Solder and shrink wrap wires together. I like to use two different size shrink wraps so I can seal over the first one. This helps fight water getting in which generates corrosion in the future. If the connection plug looks good then simply reconnect. Now move up above the engine to the fire wall. You should be able to locate the ECM relay. Don't bother with wondering if it's bad or not, it's a concern so simply install a new relay. Check the relay connection plug. Any signs of discolored or melted plastic install a new relay pigtail connection. Always Solder and shrink wrap wiring connections. Once you've covered these 3 trouble spots you can re-start the engine. I have had excellent results over the years dealing with this code following what I have mentioned. If code still comes up after these 3 areas have been addressed you'll need a wiring diagrams with numbered circuits properly identified. You'll need someone to help ohm all the circuits to verify the wiring is not the issue. Wiggle the harness while testing. If you are this far into the problem and are at a loss- you'll need to contact a Navistar International shop. They may have a traveling technician who may be in your area. These forums are full of good advice but without a wiring diagrams and a proper diagnostic procedure you'll just be chasing your tail and wasting time. Once you make the repairs clear your codes and restart the vehicle. Check for NEW code that may be active and start diagnostic of new codes. I am going to say this, about 90 percent of your problems with flash code 525 will be from the batteries to the ECM relay and wiring inbetween. I hope this helps those interested. Please feel free to add your findings and new advice since we always enjoy learning and hearing relies back. I don't get a chance to post much but I felt this is a ghost code worth clearing get up. With this code the engine won't hardly run on flat ground since the injector driver module has lost a circuit connection. Usually the GROUND white 10 gauge circuit. Still, check everything mentioned and you'll have ruled out the basic trouble spots. Good luck ! |
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bwest
Administrator
United States
3820 Posts |
Posted - 11/10/2017 : 06:36:24 AM
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| That's good advice to anyone, not just newbies! I assume you've served our great country. Thanks for your service!! I can't imagine this world without this nation in it! |
Bryan |
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1stLtDan
Active Member
USA
13 Posts |
Posted - 11/10/2017 : 06:44:23 AM
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| U.S. Marines. Thank you. I am currently working with my local school system in south-central Indiana. Have for over 30 years now. I enjoy passing on what I've learned. |
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RonF
Top Member
867 Posts |
Posted - 11/10/2017 : 07:42:30 AM
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1st. LT.
From one vet to another, Thank for your service.
Your write up for the 525 flash code is 100% spot on. I've only had on instance that was different. I had one that was difficult to start sometimes, ran rough sometimes. The only code was 525. It ended up being 5 injectors were bad. I don't know how the bus ran but it did. |
US Army retired CMBT |
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td083
Senior Member
195 Posts |
Posted - 11/10/2017 : 08:09:15 AM
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| Yea RonF i too had one with a 525 recently that also had bad injectors threw me a bit at first , but that was the only one i can remember where it was that as well usually right on as Dan said . |
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1stLtDan
Active Member
USA
13 Posts |
Posted - 11/11/2017 : 06:39:47 AM
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| I had a very rare issue with the 525 code that involved replacing the computer. Having ohmed the complete injector driver wiring circuits and changing out a dead injector, nothing helped. I learned quite a lesson from that 444E engine. After running down every circuit and connection I called for a traveling technician to be sent to the shop. He came on site and I explained exactly what I tested and gave him my results I had wrote down. I left him alone while he ran the diagnostic tree procedures. He too came to the conclusion the computer needed reflashed. He reflashed the computer. It did not work. I pulled in a sister bus and removed the computer and installed it on the bus with issues. Problem solved. Here is where it gets interesting. The tech ordered a replacement computer and informed me that he will come back once he received the computer. I reinstall the used computer back on the sister bus. Now the technician returns the following week and flashes the new computer with programing from Navistar out of Chicago area. Bus is running good, or so it seems. Tech has me sign invoice and goes his merry way. I'm out on a test drive and notice the dash check engine light comes on. Back to the shop I go. New code is right bank issues. I remove valve cover and have a helper start the engine and see two dead injectors since no oil is coming out. I take a coffee break on this one. Okay now what? I knew the wiring circuits were checked out by the testing I completed plus from what the technician tested the harness is not the problem. Did the new computer just run injectors long enough to finally find a couple bad injectors? Breaks over. I decided to do something that lead me to the only conclusion that made since. I switched the two good injectors on that cylinder head with the two dead cylinders. Started bus back up - guess what, the two good injectors went dead and the two dead injectors came to life. Sometimes you have to back track to what was the last repairs made. A new computer was installed it has a warranty so I call the traveling tech back. He runs his diagnostic after I told him what I found switching injectors. Now he shows me on his laptop where he sent the computer and vin numbers to Navistar for the flash programming and his laptop showed 444E. He calls them. Somehow, and you guessed it - they sent a flash for a 466E 6 cylinder instead of a flash for a V-8 engine. Now the technician and I had already concluded two things, either the new computer had the issue or somehow we have a program issue. Remember the sister bus? We switch out the computer again after the technician had already tried three times to get the new computer to reflash the requested 444E program. With the used computer the bus ran great. Since the traveling tech installed the new computer- which ends up bad. Why? Because he calls me a couple of days later to inform me that they tried several time to refresh it and they sent it back to Chicago for a new one. Needless to say - that was a learning experience. It just goes to show you how shops run into many different issues even while attempting repairs that you would never have thought that they would ha e ran into so many different problems all at once. |
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525 flash codes
