Leaderboard

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

The dealership definitely redeemed themselves a bit with the email. The tech is clearly insanely knowledgeable, but he is a senior master tech so I would hope he is. My only concern with a fix like that is the potential for future failure. We are hard on this car and it sees a lot of dirt roads and gets run pretty hard. If it was anywhere but behind the heater core, this would all be much easier. It would be amazing to be that knowledgeable!