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| No Crank, no power to ECU/TCM http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=84861 |
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| Author: | Sir Sam [ Mon Jun 27, 2016 11:24 pm ] |
| Post subject: | No Crank, no power to ECU/TCM |
Jeep cut off during a beer run on the way home. Glad it wasn't 7 days ago 4wheeling in southern colorado. Total loss of power, coasted awhile. Checked with DRBIII and no communication with ECU or TCM. No crank - which means no crank request by the ECU. So it sounds like somewhere I have lost power or ground on the engine harness. I have heard of some other people over the years having the same issue. While I will start checking the pinouts tomorrow, I was wondering if anyone found where the problem areas were in the past? 2005KJ. |
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| Author: | t0rquey [ Tue Jun 28, 2016 1:13 am ] |
| Post subject: | Re: No Crank, no power to ECU/TCM |
Is the EVIC reporting anything to you if the key is left in the run position before trying to start it? Sent from my SPH-L710 using Tapatalk |
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| Author: | Billwill [ Tue Jun 28, 2016 4:25 am ] |
| Post subject: | Re: No Crank, no power to ECU/TCM |
The 2005 CRD has the Front Control Module which is a bit of a gateway for the communication Buses..if this gets all crudded up with snow, water mud etc. it could hold down the whole bus..SCI and CAN Buses. ASD Relay, fuse blown. Once you start checking out the pinouts check the ground pins on the ECU/TCM with reference to +12 volts in case a ground has gone missing. 
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| Author: | Sir Sam [ Tue Jun 28, 2016 10:29 am ] |
| Post subject: | Re: No Crank, no power to ECU/TCM |
t0rquey wrote: Is the EVIC reporting anything to you if the key is left in the run position before trying to start it? Sent from my SPH-L710 using Tapatalk I do not have an EVIC. But it does sound like we are having the same issue at the same time, though the cause may not be the same. I do have a DRBIII so I can check the communications to various modules, I can communicate with the BCM but not the TCM or ECU, and since I have a no crank condition the ECU is not sending the crank signal to the starter relay. I'm thinking I have a bad ground or a bad power supply on the engine harness. |
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| Author: | Sir Sam [ Tue Jun 28, 2016 10:15 pm ] |
| Post subject: | Re: No Crank, no power to ECU/TCM |
I checked tonight and I do not have 12V with key on at pin 19 of ECU C2(lower connector). I do have 12V start signal with key at crank at ECU pin 22. So I have a point to start looking for now. |
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| Author: | Sir Sam [ Tue Jun 28, 2016 10:51 pm ] |
| Post subject: | Re: No Crank, no power to ECU/TCM |
Fuse 14 by the driver kick panel was blown. Starts now. |
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| Author: | Sir Sam [ Wed Jun 29, 2016 1:30 pm ] |
| Post subject: | Re: No Crank, no power to ECU/TCM |
Died again today right when I got to my driveway(woot). Same fuse in kickpanel blown. I replaced it and then restarted it just fine. I then tugged on the engine harness, the connectors by the TCM seemed fine but when I tugged on the bundle that runs behind the alternator it stalled on me with another fuse blown. Getting closer. |
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| Author: | jws84_02 [ Wed Jun 29, 2016 1:34 pm ] |
| Post subject: | Re: No Crank, no power to ECU/TCM |
I think that's the same wire bundle that was causing jrsavoie problems. He had an engine swap done awhile back |
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| Author: | WWDiesel [ Wed Jun 29, 2016 3:47 pm ] |
| Post subject: | Re: No Crank, no power to ECU/TCM |
At least you are in the ball park!!!! Keep us posted as to what you find, hopefully it is just a bad wire.... 
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| Author: | Sir Sam [ Wed Jun 29, 2016 5:35 pm ] |
| Post subject: | Re: No Crank, no power to ECU/TCM |
Found it. Same pink/white wire running across the top of the engine to the MAF. Plastic cable protection had come off and the wire rubbed on the intake and shorted out. Taped up wire put new loom on and wrapped with tape. All good now. 
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| Author: | Sir Sam [ Wed Jun 29, 2016 6:39 pm ] |
| Post subject: | Re: No Crank, no power to ECU/TCM |
So as a sanity check I went over to CRD#2 and test the same, pin 19 was getting power on it:  So I found when I pulled on this part of the wiring bundle the engine died and the fuse blew:  And then after poking around some more my dad noticed this, which when grounded immediately blew the fuse:  Looky there, bare wire!  Cleaned it up, pink and white just like the F1 circuit is supposed to be!  Wrapped some 3M super 35 tape around the wire and then put on new loom protected by more super 35.....but in yellow! 
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| Author: | WWDiesel [ Wed Jun 29, 2016 9:35 pm ] |
| Post subject: | Re: No Crank, no power to ECU/TCM |
Thanks Sam, I will be inspecting at my wiring in this area tomorrow to make sure it is in good shape... We all can learn from these type of finds.... 
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| Author: | Sir Sam [ Wed Jun 29, 2016 11:51 pm ] |
| Post subject: | Re: No Crank, no power to ECU/TCM |
WWDiesel wrote: Thanks Sam, I will be inspecting at my wiring in this area tomorrow to make sure it is in good shape... We all can learn from these type of finds.... Its good to document what we can. |
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| Author: | WWDiesel [ Fri Jul 08, 2016 2:39 pm ] |
| Post subject: | Re: No Crank, no power to ECU/TCM |
After seeing several posts on this forum concerning worn or chafed wiring issues, I felt it was a good idea to be proactive and redo the wiring on top of the motor where it routes across. The OEM plastic loom had gotten old and would crack and crumble upon touching it, so I redid it along with inspecting all the others real closely and making note of where new protective coverings need to be installed..... If anyone has pictures and / or locations of wiring issues in any other locations besides this one and the known one behind the 06 fuel filter bracket, please post here for future reference so it might help someone in locating a wiring problem!!!  after re-wraping:  after install: 
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