Daskuppler

We will certainly be leaving a review and reaching out to management. I was able to get a written statement from the tech outlining the steps taken to troubleshoot and their data. I don't know a whole lot about it, but it seems like it was thorough. I have one quote back that's cheaper and they are a Subaru only mechanic, just not a dealership. From the tech: Vehicle presented with intermittent issue of multiple warning lights and no data being sent to combination meter or multi-funtion display, also has no power steering assist. Upon further inspection tech found there is no communication with engine control module (ECM), Airbag system (AB), or occupant detection system (ODS). When fault is occuring, on top of the symptoms listed above, multiple DTCs are stored in various computer modules (CM). Current DTCs as follows: Body control (BIU) - U0073, U0100, U1202. Power steering(P/S) - C2543, U0073, U0100. Multi-function display U1201. Note when fault occurs DTCs and symptoms will sometimes varry depending on how interupted data signal is on CAN BUS. Some past DTCs are stored related to issue, however these DTCs are moot as then cannot be diagnosed in a past fault condition. All DTCs indicated a CAN fault of no communication with ECM or Airbag systems. Sometimes data can be sent from CM, however during fault all communication (ability to "talk" to CMs) is disrupted. Based upon time stamp and trip counter of current DTCs list tech proceeded with diagnosis of most recently set DTC U0073. Note all DTCs eventually lead to same diagnostic path. Inspected resistance of of network at DLC connector, pins 6 & 14, which indicates 90 ohms of resistance (spec is ~60ohms during normal operation). Voltage at pin 6 to ground is 0v, pin 14 to ground 2.6v (using DVOM voltage should avergae to 2.5v on both pin 6 and 14, lab scope would show more fluction of signal between 1.5-3.5v) Using CAN diagnositc table (bubble chart) provided by Subaru, the location of the CAN BUS fault is isolated to CAN BUS High data line around junctions near "6" and "7" on the provided chart. The junctions located in the area are indentified at connectors B258 and B247 for CAN High data lines. Seeing as there is no communication to ECM and AB CM (at B258), however communication is possible to P/S (at B247), this supports the fault point of between B258 and B247 or at junction B258. With P/S, AB, and ECM disconnected, CAN BUS High isolated from P/S to ECM, when the fault is occuring tech found 3 ohms of resistance in the segment of the CAN BUS High (spec ~0.2ohm) [B450#6 to B137#19 3ohms]. While monitoring resistance from P/S to ECM, tech found resistance would change as the harness was manipulated (moved/shaken) the resistance would intermittently change. To rule out fault of CAN BUS Low tech measured from DLC pin 14 to ECM pin 18 and resistance is within spec at 0.2ohms. [B137#18 to B40 #14]. To verifiy a CM is not interupting, or pulling down CAN BUS voltage, tech disconnected one CM at a time to see if communication comes back to ECM or AB, which it did not. All tests further supports a fault in the CAN BUS network at J/C B258 (bulkhead wiring harness). Unfortunately based upon the location of J/C B258 it is no easily accessible, as it's located behind the dash and heater core assembly, so deductive reasoning must be used to isolate and diagnosis this fault location. Listed below are the most significate and relevant electrical checks performed, as well as DTC descriptions. This diagnosis and findings have been verified with Subaru Techline and the DSQM of SOA. In my expereienced opionion, it's my conculsion, The only way to guarantee a proper and accurate fix for this CAN BUS fault is replacement of the bulkhead wiring harness. Replacement of ECM can be starting point, however diagnositcs does not support this will resolve the fault. All diagnostics provided by Subaru are just starting points and analytical reasoning must be used for final decision. See attached documents and media on inspection for further supporting information. Note the vehicle is not equipped with keyless access CM, remote start CM, (separate) yaw rate/g sensor, auto headlight leveler CM, eyesight camera CM, or (auto) A/C CM. Aftermarket electronics installed include (ruled out as influence or cause of fault) radio, LED high beams, LED low beams with wiring harness, LED light bar, audio amplifier. Possible subwoofer and speakers installed, however unable to verify without removal of items in back of vehicle or door card removal. DTC: U0073 - Control module communication bus off U0100 - Lost communication with ECM/PCM "A" U1201 - CAN-HS counter abnormal C2543 - Error passive Checks (at time of fault, performed with CAN BUS isolated): B40#6-#14 - 90ohms B40#6 to ground - 0v B40#14 to ground - 2.6v B40#14 to B137#18 - 0.3ohms B40#6 to B137#19 - 3ohms B450#6 to B137#19 - 3ohms B450#7 to B137#18 - 0.2ohms B247 to B137#19 - 3ohms

I'm getting quotes from 4 different Subaru specialty shops so hopefully something better comes up. The dealership has been highly reluctant to provide any root cause or photos of anything other than where the harness is visible without removing anything. All of their causes seem highly unlikely and the entire company has been dismissive and disinterested. If I could find better documentation on replacing the harness in this vehicle I might attempt it myself at this point.

Update: I spoke with the mechanic today, although not the one that did the work. They are no longer blaming aftermarket electronics and are saying that the issue is most likely in a plug in the harness behind the heater core. They say the most likely cause of failure is water or vibrations from driving 140xxx miles... They then proceeded to tell me the network is very sensitive, but that this is a 1 in a million failure. Could coolant from the heater core lines disconnect make it down there when the engine was pulled multiple times? I still think they ripped. In the harness replacing the motor and caused this. They said the issue was either a bad module or wiring, but modules were ruled out because unplugging the modules did not restore communications between them. SOA called this morning to say the vehicle is out of warranty and to offer a $1500 loyalty coupon towards the purchase of a new car. SOA cited the presence of aftermarket electronics as the possible cause again. I told them they had to prove that and they said it was up to me to push the matter if I wanted. I was encouraged to reach out to the dealership again, but there is essentially no protections from the work they did when they replaced the engine block.

So the tech went home sick Friday before New Years weekend. He hasn't come back yet. He apparently locked the car keys in his tool box. We were told there was nothing they could do so we offered to bring a spare, unlock our car, and look at the damage. They refused. I asked if they could make a key from the VIN, they refused. The tech is still out sick (1 full week now) and the service advisor's entire team is off today... So another day with no communication unless SOA calls. All of the manufacturers (Kenwood, Infinity, and Diode Dynamics) laughed at the statement that any of their devices could have caused the damage or void any warranties. They are just pointing blame. The interesting part is that no one approached them for warranty work but yet they blamed all of our equipment as the cause of failure. Kinda sounds like they have a guilty conscious.

I don't believe them or trust them at this point. I'm waiting to hear from the SOA specialist that helped diagnose. The radio works fine and has worked fine for quite some time it is wired properly, except for the Android Auto ground which is supposed to go to the E brake (I put it to the negative so you can use it without the car in Park). There is an 800 watt amp for the speakers which is direct to the battery, but is fused. The light bar is it's own fused circuit with only a connection to the battery. I can tow it to another shop and might once this all settles out. We've not agreed to have any work done beyond the diagnostics. It might even still be driveable, but they won't let us see it. There is apparently no physical damage to the wires either, despite them saying there was. They never pulled the dash so they really didn't do anything beyond run codes.

Update: dealership said the entire wiring harnesses is shot with multiple shorts throughout the entire harness including in the engine bay. They are blaming the aftermarket radio for the cause, even though it has been installed for 6 years without issues. Can a radio really take out an entire harness without ever blowing a fuse? The tech states that all of the loss of communication codes guaranteed shorts and that's the only diagnostics they did.

If I thought this was something I could tackle myself I might take you up on it. I don't think Subaru will take your parts though haha. I definitely believe the dealership damaged the harness. There's no reason there should be visible damage to interior wires in such an inaccessible spot, pictures are still elusive though. The service advisor was "nice enough" to have the sales team call us to buy a new vehicle though... Which is super sketchy given the tech has become unavailable, there's nebulous damage after they worked on it, and no estimated date to receive more information. The poor sales manager got an earful, especially after he offered us a "really good" deal on a 2020 Forester Sport with 85k miles on it for 23k with dents, dings, and scratches haha.

I called the parts department to verify pricing, Subaru sells the bulkhead for $2041. So they're charging about $2900 in labor or 3 full days to replace the bulkhead. Plus the diagnostic fee of 3 hours labor which included tearing apart the dash. I've not been able to get a labor breakdown from anyone, but 24 hours of labor seems like a lot when it's already apart and everything I've been able 5o find quoted 8ish hours.

Correct, this car has had the engine pulled and the block replaced 3 times by this dealership (different team did the engine work though). The block was defective from the factory with oil consumption but we could never get it replaced under warranty. There were no can us issues prior to the work and they popped up about 11months after the the final replacement I was told they found damage on the can bus behind the heater core, but they were too busy with a other customer's vehicle in Friday to send photos with the $5,000 bill and the tech is sick today with no estimated return date (same games they played with the engine replacement). So still no pictures of said damage. The dash has never been removed from this vehicle. It does have an after market stereo, but I didn't get anywhere near the heater core for that install. Prior to taking it to them, I checked the ECM and TCM connections in the engine bay and cleaned them with contact cleaner. The connector on the ECM does not lock in place anymore, but I don't know that it did before the engine replacement. I have tried to get a breakdown of labor and parts but they have not provided anything yet.

Thanks for looking. The issue presented itself as intermittent canbus communication loss between multiple modules. I had close to 20 codes that would come and go. I still don't really understand how the wires could get damaged behind the heater core... Hopefully the pictures will tell a better story when I get them. I'll post back with findings.

They told me the damage was find behind the heater coil. The tech was supposed to call me but miraculously had to go home early and I was pushed off until Tuesday. I'm supposed to get photos of the damage and a root cause but who knows. They supposedly aren't several hours on the phone with Subaru engineers to get it all worked out. We'll see. How hard are these wiring harnesses to replace? They're charging something like 4k in labor which seems excessive since diagnostics was only 3 hours which included. Complete tear down of the interior.

Hello Everyone, I have posted about canbus issues in the past. The issue has been isolated to damaged wires behind the heater core. I have been quoted just shy of 5k to replace the entire harness. Is there any way these wires could have been damaged during an engine block replacement? My thought is when the heater core lines and ac lines were disconnected, the tech was a little rough and the wires got pinched or knicked. Cheers,

Update: after cleaning the connectors in the engine bay, we drove the vehicle about 1000 miles without issue. This morning, at idle and neutral (shifting from park to drive) a bunch of codes came back along with some new ones. Restarting the car cleared everything except the fuel sensor code. Wiggling the previously mentioned plug did nothing. The car was driveable but sluggish and hesitant to shift. General Codes: U0101 Stored: lost communication with TCM U0101 Pensing: lost communication with TCM U0100 Pending: Lost communication with ECM/PCM "A" U0101 Permanent: lost communication with TCM ABS/VDC Module: C1431 Current: AT Abnormal U0100 Current: CAN-HS ECM No-receive Data TCM Codes: U0100 Current: Lost communication with ECM/PCM"A" Engine Codes: P0462 Current: Fuel level sensor circuit-low input U0101 Current: Lost communication with TCM Meter Codes: U0073 History: Control Module Bus "A" off U0151 History: Lost communication with restraints control module U0100 History: lost communication with ECM/PCM"A" Multi Function Display Codes: U1201 History: H-CAN Error Counter Fail U1201Current: H-CAN Error Counter Fail Electric Power Steering Codes: C2543 Current: Error passive status Body Integrated Module Codes: U0100 History: lost communication with ECM/PCM"A" U0100 Current: lost communication with ECM/PCM"A" Here is a link to the freeze frame data, it is the same for all of the codes:

I'm not sure if they're available in that size, but the Continental TrueContacts have been great on our '14 Forester. We see several hundred miles of gravel roads per year and have never had a failure (apart from getting nails/screws). We get about 50k out of them and they are great in the snow (for an all season).

We finally got it back from the dealership where they told us they drove it all over the place trying to get the code to come back...they drove a whole 8 miles, but I digress. I got some contact cleaner and pulled the connections off the ECU, cleaned everything up and put it back together. Everything looked fine, except the top connection in the ECU won't snap and lock in. It looks like it should, but won't. I tried using some channel locks to gently push it together and it would slide an extra 1/16th" but went right back to where it was as soon as I let go and would never lock. Could this be the root of the problem? The connector looks like it's together all the way. The car runs fine now, time will tell. From what I read, the TCU should have beenounted right below the ECU but I didn't see anything else there, does anyone know where I might be able to find it to clean the connections there as well?

I agree with pretty much all of that. We live in a throw away society and pretty much everything is crap. My assumption is that all of this equipment is inside the car behind panels and is connected with that single 2 conductor braided wire. It seems like it's highly unlikely the wire went bad being inside the car where things are relatively protected. That leaves the modules I presume there's no real way to figure out where the break in communication is based. On the fact that only certain modules were reachable? I'm assuming that the communication is fairly linear since a bus system requires the signal to pass through one module to the next. It seems like, if you were willing to throw some. Money at it, that you could assume if communication dropped off after, say the TCM, eeither the TCM is bad, or the module immediately following it. I obviously. Don't understand how all of it is setup though.

We bought it with 20k miles on it in May of 2017. 141k on it now. The car was originally sold in Washington, but came from the Midwest before it was traded in at a dealership in Colorado. I don't know how much time it spent in each locale. The car is still relatively rust free apart from the usual suspension parts. It has had its own spot in a garage since we purchased it.

The stealership said there were no hard codes everything was fine so they can't do anything. The CEL was on and the cruise control light was flashing when it went on the tow truck... Is there anyway to troubleshoot it with an intermittent issue and no hard codes?

I don't think we're going to tackle this one, we have an international trip in two weeks. We'll see what the dealership says. Where are these control modules located? The ECM looks like it's about 1k and the TCM looks to be about $600...

Update again: short story... GD was right as usual. Long story:car was good for about 400. Miles, no codes, no problems. Sitting at a stoplight the dash light up like a Christmas tree. All systems turned off, transmission temp flashes, car went into limp mode. Drove it home cooked the code reader up and had two codes. U0073 and u0100 (loss of communication with ECM/TCM). Only engine and transmission codes where available, no other modules were listed or available to scan. U100 was listed as a transmission code, U0073 was on the engine.

I faintly recall seeing some relays in there when I ran the amp wire, but I can't say for sure. There's been very little little moisture in the car and we live in a dry climate, but anything is possible!

Update: after disconnecting the driver's heated seat, the code has not come back after several drive cycles. The bottom heater element has been broken for about a year, maybe it finally degraded to a point where it was causing interference. 🤞

Great article! The issues go far beyond where I thought they stopped! I would assume if you could remove the infotainment system and replace with an aftermarket, you would be fine... but most aren't removable anymore.

Okay, that makes sense. Although annoying. I've heard Optima. Went to spoob, but it was better than store brand crap for almost the same price that wasn't even a sealed battery.

Voltage was at 12.85.volts after a 10 minute drive. With engine off and accessories in(stereo, high beams, blower, and light bar, voltage was 11.91 and dropping .01 volts every 2-3 seconds. This doesn't seem that bad, should it be replaced? Battery charger said it was at 75% charge.