mdixon Posted July 26, 2023 Share Posted July 26, 2023 Hey everyone, I've got a truck I'm having some trouble with. 2010 cxu613, dash lights up but won't crank. Battery voltage good, relay good, all ignition relays/fuses checked good. Ecm is sending voltage to relay. However I'm getting a mid 144 pid 200 fmi 9 in the VECU, ECU data "operation failed" truck sat for almost a year cuz of bad injector cups, were about to do a inspection and see if we wanna save it. I've cleaned all the ground on the starter and on the block by the pcv seperator. Quote Link to comment Share on other sites More sharing options...
mdixon Posted July 27, 2023 Author Share Posted July 27, 2023 I've started chasing datalink/can bus wiring. With everything plugged in pin C reads 2.3 volts, pin D 1.9. When I unplug the engine ECU pin c voltage increases to 2.65v and pin d voltage remains constant. Resistance across can lines is 120ohms. Unplugging various can bus sensors doesn't change voltage at pin C or D, however in getting over 3v at all the sensor connections at the harness on can high wires. Unfortunately I don't have a diagram for the ecu pinout and I can't get into macks ESD right now. Quote Link to comment Share on other sites More sharing options...
mdixon Posted July 27, 2023 Author Share Posted July 27, 2023 So, I've got my data link back after swapping a good ecu. However I'm still not getting power to the starter when turning the key. Mid 144 Ppid 3 Fmi 3 I can't find anything on this code, I'm stumped. Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 27, 2023 Share Posted July 27, 2023 With all MP engines that won’t crank . First check engine hours in the dash cluster . Usually under Trip Info. If no hours are shown and only hash marks, check the bottom connector on the engine Ecm for power and ground. Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 27, 2023 Share Posted July 27, 2023 The engine ecm controls the ground for the small auxiliary starter solenoid that on the starter. The engine ecm has the final say on whether to start or not by completing the ground. Using a test ecm and if you can now see engine hours then most of the time you have a failed engine ecm. The test ecm could be from a automatic trans truck or be programmed totally different than the original so sometimes they won’t start. I have see a few times that the power and ground were weak to the engine ecm. It might show 12 volts and ground but under a load there is not enough voltage or ground to carry the load . Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 27, 2023 Share Posted July 27, 2023 Power comes through firewall on the second connector down , pic C. This is the back of the fuse box . Then it comes through a 16 pin connector up by the foot valve/wiper motor. Quote Link to comment Share on other sites More sharing options...
mdixon Posted July 27, 2023 Author Share Posted July 27, 2023 So I think there's a short to power somewhere, key on the starting solenoid + wire has 3.5v on - battery post. Ecm connector + pin to the lug hoop has 0 ohms no other harness connections have any continuity to the hoop. Whatever took out the engine ecu seems to have also killed the abs module, because that's throwing a 254 code now that the ecm is on the can. The new ecm is from another truck that's basically exactly the same, ordered for fleet use with consecutive vin#s Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted July 27, 2023 Share Posted July 27, 2023 you will never find the great info that MackPro provides for free anywhere but here.. 1 Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 27, 2023 Share Posted July 27, 2023 The ecm swap should have let it start. Check ground stud that welded to frame behind battery box. Also check the fuseable link ground wire that goes from negative battery to that ground stud. Had weird issues with this wire and stud. 1 Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 27, 2023 Share Posted July 27, 2023 The small chrome auxiliary starter solenoid/relay that’s bolted to starter is where the magic happens. The small red wire pretty much comes from the key switch and starter relay in the fuse box. The black wire goes back to the engine ecm. These two wires are in a loom together and come off the back of the engine harness and over the top of the transmission. Turn key off and let truck power down . The key on and then to start position. You have one 5 second shot to check the voltage on the red wire . Which should be 12volts. After 5 seconds the VECU kills the starter relay voltage. You have to cycle the key back off to re-test. Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 27, 2023 Share Posted July 27, 2023 Mid144 PPID-3 FMI-3 is Starter relay output , voltage above normal or shorted high. Possible cause is short in harness or relay Quote Link to comment Share on other sites More sharing options...
fjh Posted July 28, 2023 Share Posted July 28, 2023 3 hours ago, Joey Mack said: you will never find the great info that MackPro provides for free anywhere but here.. 👍💰 Quote Link to comment Share on other sites More sharing options...
mdixon Posted July 28, 2023 Author Share Posted July 28, 2023 10 hours ago, Mackpro said: The small chrome auxiliary starter solenoid/relay that’s bolted to starter is where the magic happens. The small red wire pretty much comes from the key switch and starter relay in the fuse box. The black wire goes back to the engine ecm. These two wires are in a loom together and come off the back of the engine harness and over the top of the transmission. Turn key off and let truck power down . The key on and then to start position. You have one 5 second shot to check the voltage on the red wire . Which should be 12volts. After 5 seconds the VECU kills the starter relay voltage. You have to cycle the key back off to re-test. Yeah, I've got constant 3.5v with key on on that red wire. I'll have to yank the doghouse to chase the wire any further. Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 28, 2023 Share Posted July 28, 2023 Your fuse box down by your clutch pedal, does it have a rubber boot that goes around it that sticks out a couple inches along the side? There was a recall on most all CXU, GU and CHU’s. Water was getting in the fuse box and shorting out relays. https://static.nhtsa.gov/odi/rcl/2014/RCRIT-14V078-3643.pdf Quote Link to comment Share on other sites More sharing options...
mdixon Posted July 28, 2023 Author Share Posted July 28, 2023 Yes it does, f38 tests good, 12.5 on one leg no voltage on the other, in going to check the plug on the firewall now Quote Link to comment Share on other sites More sharing options...
mdixon Posted July 28, 2023 Author Share Posted July 28, 2023 This is key on, - on battery lug Quote Link to comment Share on other sites More sharing options...
mdixon Posted July 28, 2023 Author Share Posted July 28, 2023 Which relay actually sends the 12v signal out to the starter relay? Quote Link to comment Share on other sites More sharing options...
mdixon Posted July 28, 2023 Author Share Posted July 28, 2023 Pin 59 on the harness has resistance, 20ohms, other 2 grounds 0 ohms. Both 57,60 have battery voltage with key on Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 28, 2023 Share Posted July 28, 2023 Very small relay in kick panel fuse box. It must be inserted correctly or no start. The blades must be horizontal. Not vertical. Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 28, 2023 Share Posted July 28, 2023 Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 28, 2023 Share Posted July 28, 2023 Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 28, 2023 Share Posted July 28, 2023 Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 28, 2023 Share Posted July 28, 2023 Pin 85 should have 12 volts when key turned to start position Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 28, 2023 Share Posted July 28, 2023 Testing the relay by it’s self. 80-140 ohms across pins 1 and 2 Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 28, 2023 Share Posted July 28, 2023 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.