CAN this Crashed Caddy Communicate? (ABS-Steering-Airbag...2014 CTS)

hi everyone welcome back to Pine Hollow out of Diagnostics 2014 Cadillac CTS you see it's disassembled this car got towed here about an hour away from another YouTuber uh Todd from the channel unwrecked so he buys auction cars restores them sells them and he says he loves doing body work but he doesn't like electrical that's why this car is here he said it's setting communication codes in the power steering I think the ABS the airbags so he just towed it here it's obviously it's not assembled yet it does start and run he wants these communication codes figured out so this is going to be a network diagnosis so first things first we want to do a full Health Report see what's online see what's offline see what codes are being set I'll show you what the car does so let's start it up see what warnings are saying traction control R okay traction control off power steering drive with care [Applause] everything else airbag problem and anything else okay he's got all the lights disconnected obviously so it's gonna set a whole bunch of light warning codes headlamp leveling okay so here's a full Health Report a lot of modules and quite a few of them are red now I did a code clear restarted the car these came back uh I'll show you the full health report but we can just go one by one uh nothing interesting in the BCM these are the ones so parking brake control module he's got the console torn apart not interested in that okay power steering control module shut the vehicle off here control module communication chassis expansion can bust off okay that's definitely part of the problem last communication with steering wheel angle sensor module last communication with electronic brake control module on chassis expansion can bus okay invalid data received from electronic brake control module let's see what the ABS is setting again same u0077 this chassis expansion can bus off plus communication with inflatable restraint you know the airbags lost communication with steering wheel angle sensor and Todd said that he did replace the steering wheel angle sensor and that didn't do anything there's steering wheel angle sensor module see if that's setting any codes to read fault code okay that's supposedly happy but anything else here nothing else interesting and the airbags where is the airbag module here sometimes they label them in weird ways Powertrain that's Happy other human control interface module you don't care about that sometimes you just you do report and see let's open that up and look for the airbags here we go inflatable restraint sensing and diagnostic module so irsdm is our airbags it's also setting a u0077 control module communication chassis expansion can bus off so the question is how can these modules talk to the scanner but they can't talk to each other we need right off the bat a wiring diagram of this whole information bus all the networks and then see how these modules are tied together and how they're talking to the scanner all right so the owner he already printed off the colored redrawn diagrams and there's nine pages here a lot of modules a lot of Networks um so you know here's our DLC and we have several networks connected to the DLC that doesn't mean all the networks come to the DLC there could be a Gateway but let's find the modules that are fussing about you know having communication codes power steering abs and airbags and again I looked through all the diagrams and you have to go to almost the last page here okay here we go there's the airbag module and let's see what network it's on so there's low speed GM Lan serial data that's single wire green and then high speed Jam Lan serial data two that's the second High Speed network so it's on two networks and I think what's going on here it's talking to the scanner on the low speed you know setting codes but you can't talk to any other module on this High Speed network now what's on this second you know two high-speed Network let's see hey look there is our steering wheel angle sensor so that module we're concerned about airbags we're concerned about and some of these other modules it may or may not have there's left seat belt retractor motor logic rear differential clutch control um you know what's on what's on the next page here there's the electronic brake controller so that's on the High Speed 2 Network that's setting codes power steering control module definitely that's on the high speed 2 Network you can see that's connected to here um and this is a pass through so the network you know goes from the ABS to the power steering control and then out with or without restraint Provisions to the next page you could have a multi-axis acceleration sensor so a lot of variables here but that is the network that's setting the faults this GM high speed GM Lan serial data too now GM has really nice OE diagrams that break these networks down you know by Network and then they have the uh the codes the RPO codes that tell you exactly which options this car has so that's my strategy here let's go to the OE diagrams let's take a picture of the RPO label and see exactly which modules this thing has and also which connectors are in the network and go from there all right so here are the OE diagrams that's the DLC then we have GM Lan one of two this is the first high-speed Network we don't have any problems with that Network and two of two and then this chassis high speed GM LAN this is the one that we're concerned about now I printed them off so it'd be a little easier to see and also here's the RPO sticker so we can reference this and see exactly which options this car has so here's the OE diagram starting with the ebcm we're dealing with the white and blue and yellow wires next is the power steering control module yes that's equipped so there's two modules there and then we have these RPO options so ax7 or no ax7 well if you go alphabetically we have axj but no ax7 so immediately you just cross that off we're going straight through and then you gnuvz it does not have this cross that off it does not have ufq cross that off front parking Aid assist uh multi-axis acceleration sensor suspension control module f55 again reference the sticker we only have three F codes there are no that's no f55 so this is more of the base model I guess again does not have active safety control module so you can see how many modules are not equipped here so far we just have ebcm pscm power steering let's go to the next page come in here do we have g96 no chassis control module we don't have rear differential clutch control module we don't have this is for the fancy all-wheel drive this is just regular all-wheel drive come here we don't have ax7 finally steering wheel angle sensor and airbag module so check that out we just eliminated one two three four five six seven eight modules and we we're down to four airbag steering wheel angle sensor power steering control electronic brake control module and those are the only codes that were stored so we're on the right track what's the next logical step here so we know what Network's affected and we know exactly where the terminating resistors are they're even labeled 120 ohms in the ebcm and 120 ohms in the airbag module so what I want to do is one disconnect the battery so we don't have any stray voltages on these Networks put an OHM meter across pins 12 and 13 at the DLC we'll see what that reading is if the network is all connected we should have 120 divided by 2 which is 60 ohms this is just like a regular can network is just you know there's two of them here if we get something different there might be an open circuit so let's get an ohmmeter at the DLC all right so I'm going to turn off my charger disconnect that from the battery take the battery clamp off also keep in mind this is a electronically controlled trunk so just latch this so if you shut the trunk nothing bad will happen it won't latch okay DLC unplug our dongle your favorite meter out set it to ohms and let's probe pins 12 and 13. beautiful 120 ohms okay so it's reading one of the terminating resistors the other one you know there's an open circuit somewhere in this network and we're dealing with only four modules so let's go back to the diagram and see where we can split this network is there an intermediate connector that's easy to you know easy to unplug um hopefully this will be pretty efficient Okay so what we just did is we measured the resistance here 120 ohms across these two pins so I assume since they're connected right here they're going through the steering wheel angle sensor and measuring this resistance in the airbag module now that's not necessarily the case it could be going all the way and measuring this resistance so what I want to do is find an intermediate connector for example there's a x150 x 150 right there basically if we disconnect this we eliminate these modules and if our resistance doesn't change then we know that at least this leg of the circuit is good so let's um find this x150 and again all data to the rescue you just type in x150 in locations under connectors and engine compartment there's a strut Tower looks like number one is x150 and it says body harness to engine harness bulk connector okay and what it looks like in Connect reviews is this I guess 54 pin bulk connector so let's keep the ohmmeter on the DLC find this connector and disconnect it so very convenient that the fenders are missing this connector is x150 it has the small pins and the bigger pins and what I'm seeing is it's not latched completely all the way in but let's just unplug it take a look in here there's the female side I'll take a look at the pins in there what did our ohmmeter do our oh meter still showing 120 ohms so my suspicion was right we're going after this abs and power steering control module you know in the engine compartment let me just double check that all the pins are good in here and we can see the PIN numbers and then we can get the ohmmeter here and do some checks at this bulk connector all right so at connector x150 again the diagram is absolutely everything here so we're coming in from the body harness then on pins 42 and 43 blue and yellow white wires if you go to the power steering control module this is the engine harness and then they come back on pins 36 and 37 back to the body harness and finally to the ABS unit so which sides the body which side's the engine well again visual inspection this fat cable with the female connector that comes in you know that fat Loom from the body and then once it goes to here you see curve it back around that goes down and the engine computer is actually right here and then you see that goes down to the engine so that makes sense this is body harness this is engine harness so on the body harness we're coming in on pins uh what was it again 42 and 43. those are right here on the bigger pins right in the side in the middle row and you can always you know double check your wiring colors there's the blue and yellow and there's the white it's coming in from the body so if I measure this distance here we should see the resistance the same resistance that we saw on the DLC at the airbag connector if the wires are intact so nice easy check Bingo we got 120 ohms okay awesome now so we verified from here down good check next check we're going to do is move to pins 36 and 37 and check that weight towards the ebcm we should also see 120 ohms so pins 36 and 37 are going to be in the next row [Applause] let's see here this one and this one okay again blue and yellow and white yep 125 ohms okay perfect so we just verified that going that way is good check so we're very close now we have to go through this power steering control module uh-huh so we can do a resistance check this should be straight through from pins you know I'm now on the engine harness side 36 to 42 and then 37 to 43. you could do that I have a I have a feeling we're gonna have to go to this power steering control module um we could do very easily is just jump these and eliminate the power steering control module and make sure we have 60 ohms at the DLC uh but that's you know not necessary because we know we have 120 Ohms on one pair 120 Ohms on the other pair and if they could get connected through the power steering control module we should have 60. so let's do some resistance checks on this connector now and see if there's a broken line or if they're both open or what's going on with this power steering control module all right I got some AES wave adapters for those pins again we're going towards the power steering control module and coming back so on one pair the blue and yellow should be continuous and then the weight should be continuous so right now I'm connected to this pin and this pin and those are the white and the white look at that perfect continuity zero ohms let's move the leads to the other pair of wires the blue and yellow wires so we'll connect that to here connect that to here all right here we go open circuit so again what do we just prove the white wire going all the way through the pscm is good the blue and yellow wire bad so we're really close we need to get to this power steering control module and do our checks at pins four and nine look at this connector see if there's any wiring issues we're almost done okay under the car here's the connector for our power steering so we can see all the network wires the blue and yellow and the white so let's unplug this guy foreign s look good beautiful there so we have one two three four five six seven eight nine wires and now we have to see which pins they are we have access to that connector so we can do a continuity check for all four Network wires from here to that connector well actually we know the white circuit's good the blue and yellow is the one we're worried about all right so lunio wire let's first check pins 36 at the connector to pin four at the pscm so I sent 36 I got my ohmmeter on C and make sure we're on pin 36 not 42. okay that's definitely pin 36 yes and here we want to be on pin four pin four open circuit okay let's check the other one so pin nine two 42. this is going to be 42 right here 22 Mega ohms it's still open circuit so it looks like here it's open and here it's open it's one of the chances of that well they're going through the same harness I guess it looks like could be some harness damage here so that's the engine harness here goes down goes down across the underside it's right here here here up here and then right here [Applause] I don't see anything too suspicious yet we'll take a closer look here for any uh harness damage I mean this thing was wrecked in the front he said he replaced the radiator but the condenser is still okay that looks all Factory clipped in the condo it's not smooshed okay let's uh find anything interesting we'll show it on the camera but we have to find something well need a little a little error so at the pscm is 10 pins I was on not the right pins here so let's double check this again from pin 36 36 to pin 4. so that wasn't on pin four again you can tell by wiring colors I was on the blue wires not the blue and yellow so pin four is actually right here and check it out so that wire is actually good okay what about the other one so 42 to 9. it's going to be this one here there it is there's our 5.4 kilo ohm resistance that we saw on the initial reading so now we know that 36 to 4 is this is okay but 9 to 42 is bad right here so now we have to go hunting by for this basically open wire and what we could do is set up the ohm meter and just do a gentle little wiggle check and see if if we can find I'm just going to pull the harness a little bit here it's not changing much at all okay and kind of wiggle it oh stop it seven kilo ohms like look here here my connector is fine oh where is this probably here here it goes down make sure that pin itself isn't like pulling out you want to do a little pull check at the connector itself resistance is not changing I bet this harness is going to be nicked somewhere where it's hard to see hmm all right so I'm touching this part of the harness right here we can see our resistance is actually jumping around quite a bit I think we're pretty close to locating the problem so we push it in the resistance goes down if I pull on it the resistance goes up not very much comes down and over this cross member [Applause] could have been pinched somewhere we might have to open up the harness right here and just do the Keith tug test and see where that wire snaps there we go I can see the blue and yellows the less intrusive you are the better so let me just get in here and pull on these two wires see which one it is all right so here are the two pairs with network wires going to and from this power steering control module so I pull on this blue and yellow not much is changing if I pull in this blue and yellow there it is so if I pull hard enough we're done all right so pulled the harness through a little bit to expose both ends of the broken Network wire so let's just clean this up and strip it back a bit we have plenty of Slack to we don't have to extend it or anything and we'll just wrap this up real nice so I assume this happened because of the accident and then the wire got exposed and eventually broke yay we'll have to clean that up with some sandpaper solder it together clear the codes and then Todd it unwrecked we'll take it from here the wire's all cleaned up warm up the ts-100 let's go fast this thing warms up boom make sure the solder Wicks into those strands beautiful solder joint do a little tug test slide on the shrink wrap and she's a little mini torch to uh toast it on there beautiful plug everything in clear the codes out all right so here is the repair power steering modules plugged back in and hey zero ohms perfect so let me plug this in and we'll measure the resistance that the DLC we should see 60 ohms all right now the DLC pins 12 and 13. the thinner 60 ohms perfect let me wrap up the harness we'll reconnect the battery rescan it clear the codes out make sure this car is ready to go all right full code scan let's clear all the dtcs in the vehicle and see if anything comes back all right here we go start it up all right [Music] change oil soon airbag all right one more smart scan and we'll save this as after a pair all right so we have a lot fewer codes now we're going to see dimming circuit don't care airbag obviously the driver's knee airbag is removed so don't that's normal headlamp control module the headlights are disconnected part brake switch is disconnected that's normal ebcm says and validator received from prank break control module yep USB and cold start rough idle because this thing's eating coolant as a blown head gasket and but that's it we solved the network communication faults so thanks a lot Todd for bringing me this Cadillac and check out Todd I'll leave a link in the description it's called unwrecked Uh he does some pretty nice body work so thanks a lot for watching and we'll see in the next one bye

Channel: Pine Hollow Auto Diagnostics

Views: 64,468

Keywords: GM, CAN, network, communication, open, circuit, wire, diagram, wiring, trace, fault, DLC, harness, repair

Id: DPsZ2sG1O7o

Length: 33min 27sec (2007 seconds)

Published: Sat Aug 05 2023