Jomorisn Posted August 6, 2021 Share Posted August 6, 2021 I have a 2002 CH 600 with a 427 it has started with this problem of not starting or stalling when driving and sometimes starts right up and today it would not start for 45 mins and sometimes run for weeks with out an issue It shows codes 6 and 4 and the dash displays No Info it died today sat for about 45 mins fired and I was on my way . Could it be a bad ECM? overheating cooling and then starting back up when it cools down? I have posted this before and have cleaned all grounds and my isssue continues I don't think its a harness problem any and all help would be great thanks in advance Thanks Sick CH Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted August 6, 2021 Share Posted August 6, 2021 This is the Yellow and Green "twisted pair" of comm. wires. easy to trace because they are the only yellow and green wires.... Under the hood is a triangular Duetch connector where the steering column comes through the firewall. if it is not secured it can loose its connection, I believe you have a gray 6 pin comm. port by the clutch pedal. the wires are there too, the low line has about 1.7 volts and the high line has about 2.5 volts. did you check that when the truck is running, and then when it shuts down? these wires go to the VECU behind the kick panel on the right side under the metal panel, pull the floor matt back to get to the lower row of screws. I should have asked this next one first.... Did you check the condition of Fuse #40 in the EPDM under the hood? pull the fuse and check the terminals tension, (holding ability)also check voltage. 12.6 with engine off, 13.8volts -14.3volts, with engine running. ecu's can go bad, but lets just look for a weak wire connection first.. Wiring issues can really make a person mad.. many times the solution was a bad wire or connection. With the engine running, you can wiggle these wires and see if a change happens, I will keep thinking,,,,Jojo 1 Quote Link to comment Share on other sites More sharing options...
Bullheaded Posted August 6, 2021 Share Posted August 6, 2021 Was also a bad mass ground point problem too. If I remember right it was near the left A-pillar just under the windshield? A ground bolt with a whole bunch of wires on it. My 2000 did that for years until we finally got sick of it and I got a 9900i with a Cat. It would randomly show the lightning bolt on the dash and shut down then start right back up going down the highway. And it was like a light switch. My 460 will pull along side 475 Cat's when it decided to run, then next hill you would think the clutch was slipping because it would not pull at all. Even my dealer could never figure it out. They changed ECM, wire harnesses, etc. And it turned out to be that ground. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted August 7, 2021 Share Posted August 7, 2021 yes Bullheaded, you are right... If you use the same procedure to fix a 9-2 code, you will be inspecting all of these grounds.. he has posted this issue in another thread and we addressed that, Of course we are not doing the trouble shooting, so who knows if all has been inspected,,, ( with respect) .. Jojo Quote Link to comment Share on other sites More sharing options...
Bullheaded Posted August 7, 2021 Share Posted August 7, 2021 Been a long time and my memory is shot, but thought I'd throw that in the mix too in case it was a separate issue. I actually learned of that fix from this site. Unfortunately it was many years after the truck was gone. Quote Link to comment Share on other sites More sharing options...
Vmac3 Posted August 8, 2021 Share Posted August 8, 2021 Disconnect the batteries and check the resistance between C and D at the communication connector. You should see 60 ohms there. If it's lower then you may have a short to ground. If it's higher around 120 ohms the you may have a broken communication wire. Also make sure you remove any aftermarket equipment that may be tapped into the J1939. Assuming you have a manual transmission there should be nothing else other than the ABS module and of course the engine and vehicle ecu connected to it. V 1 Quote Link to comment Share on other sites More sharing options...
Jomorisn Posted August 8, 2021 Author Share Posted August 8, 2021 Vmac3, Is the communication connector the green and yellow wires? And thank you for your reply. Thanks John Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted August 9, 2021 Share Posted August 9, 2021 yes, the "Twisted pair" of green and yellow is the 1939 line.. Quote Link to comment Share on other sites More sharing options...
Vmac3 Posted August 12, 2021 Share Posted August 12, 2021 Hi John, Have you made any headway for this communication error? V 1 Quote Link to comment Share on other sites More sharing options...
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