SweetTea41 Posted March 4, 2022 Share Posted March 4, 2022 Swapped in a JDM ej20, swapped ej25 intake and wiring onto the ej20. Did a test fire once all was plugged in, started fine although took a bit of cranking to go. Threw two codes, don't remember the exact codes but I do remember what they meant. One was bank 1 running lean and the other was faulty cam position sensor. In the process of removing the intake manifold to get to the cam sensors a lot of the old hoses disintegrated. After replacing the intake manifolds hoses, I installed it. The motor cranked twice then stopped and gave me the code ER HC in the odometer. First thing I did was search up the code. Found that the code could be many things electrical. So thinking to hook up an ob2 reader to check for more specific codes. The reader reported back that the car is not communicating with it. Checked all grounds, all good. Checked both the passenger side large connector and brown connector under inter cooler. Both are in good shape. All fuses are good as well. Assuming that the green plugs reported by others with similar issues are NOT plugged in due to the car starting before the intake manifold was removed. I don't know what issues the ob2 port not communicating implies. Currently stumped and don't know what to check next. Link to comment Share on other sites More sharing options...
lagwagon Posted March 4, 2022 Share Posted March 4, 2022 There is a very old tsb for intermittent communications issues that give similar issues. It’s possible your ecu was never replaced and you are just now having the issue. It’s also possible you accidentally cut a wire when you reinstalled the IM or one of the grounds is not good enough even though you checked it. Did you check your battery voltage or try putting on a jump pack or charger? Link to comment Share on other sites More sharing options...
whitexc Posted March 4, 2022 Share Posted March 4, 2022 Someone very recently had an episode where the Cobb AP wouldn't connect. I forget what they found but possibly similar? Sent from my SM-G996U using Tapatalk Link to comment Share on other sites More sharing options...
SweetTea41 Posted March 4, 2022 Author Share Posted March 4, 2022 All my grounds are good due to having to reinstall them when the engine went in. Cleaned and good contact made. The battery was bad after sitting for so long during the swap but just had it replaced with a new one today. Link to comment Share on other sites More sharing options...
omnicron Posted March 4, 2022 Share Posted March 4, 2022 Check fuses? Link to comment Share on other sites More sharing options...
Pleides Posted March 4, 2022 Share Posted March 4, 2022 It's not incredibly uncommon that, after an engine swap, the car running out of fuel, or whatever else causes the car to take a long time to crank that the car leaves a check engine light for a bad crank position sensor. The other code is for your catalytic converter being bad/modified, I'm guessing. The lack of connection to OBD2 sounds like an issue with the wiring harness. Best of luck. Last time I saw an issue with a Subaru not connecting devices to OBD2 the car had been in a lake. I'm assuming yours hasn't, or at least let's hope not! Link to comment Share on other sites More sharing options...
lagwagon Posted March 4, 2022 Share Posted March 4, 2022 Someone very recently had an episode where the Cobb AP wouldn't connect. I forget what they found but possibly similar? Sent from my SM-G996U using Tapatalk Mine losses comms frequently when trying to log. I haven’t investigated it yet but my ecu was replaced under warranty and since then connecting scan tools has been hit and miss. The AP connects reliably for live data though. Other than people suggesting there is an issue with the obd2 port (bent pins? But mine aren’t bent) I haven’t seen much else. Link to comment Share on other sites More sharing options...
SweetTea41 Posted March 5, 2022 Author Share Posted March 5, 2022 Going to do continuity tests on the engine wiring harness tomorrow. I feel that it is something there because it worked before coming off then not when back on. If all is well with the harness I'll check the ecu next. Link to comment Share on other sites More sharing options...
JoeInOregon Posted March 5, 2022 Share Posted March 5, 2022 Someone very recently had an episode where the Cobb AP wouldn't connect. I forget what they found but possibly similar? Sent from my SM-G996U using TapatalkIt was me. It was definitely mechanical, I plugged in and unplugged the odb port about 100 times and some wiggling and it finally connected. If I have trouble again I will be re pinning the odb port Sent from my Pixel 3a using Tapatalk Link to comment Share on other sites More sharing options...
SweetTea41 Posted March 6, 2022 Author Share Posted March 6, 2022 There is a very old tsb for intermittent communications issues that give similar issues. It’s possible your ecu was never replaced and you are just now having the issue. It’s also possible you accidentally cut a wire when you reinstalled the IM or one of the grounds is not good enough even though you checked it. Did you check your battery voltage or try putting on a jump pack or charger? Would no communication with the ob2 be a symptom of a bad ECM? Link to comment Share on other sites More sharing options...
lagwagon Posted March 7, 2022 Share Posted March 7, 2022 Would no communication with the ob2 be a symptom of a bad ECM? According to the TSB, that is one of the symptoms. No communication can also be a wiring issue unrelated to the ecu, or a voltage or grounding issue. I wouldn't replace the ecu just because there is no comms through the port. In my situation, some tools will communicate, some won't, sometimes the Accessport will log, sometimes it loses comms when attempting to log. Link to comment Share on other sites More sharing options...
SweetTea41 Posted March 9, 2022 Author Share Posted March 9, 2022 Update: Took the car to a dealership. Told them about the swap and the code. Only for them to tell me that because its not OEM they can't/won't go any further on diagnostics. Next thing I am going to do is pull the engine wiring harness off and do continuity testing to see if there is a broken wire. As well as test the sensors. Link to comment Share on other sites More sharing options...
SweetTea41 Posted March 21, 2022 Author Share Posted March 21, 2022 Update: Replaced the wiring harness due to severe damage to a lot of the wires being broken. Didn't fix the ER HC code. Got luck and found a similar year legacy GT at a local junkyard that still had its ECM. Swapped the ECM and fixed the ER HC problem. New problem is that it cranks but won't start. Tested the fuel pump and it's getting fuel. Haven't tested spark yet. Link to comment Share on other sites More sharing options...
Infosecdad Posted March 21, 2022 Share Posted March 21, 2022 Did you reprogram the new ECU to talk nice with the rest of the system? You may need to update the VIN in the replacement ECU so it's recognized by the system, and you can start the car. The instrument cluster, BIU, and ECU all need the same VIN in their firmware; new ECU will have a different VIN and starting is likely disabled. It's a theft deterrent feature. You may have to do it yourself, not sure you'll find a dealer that will be willing to do it with your setup, but not sure. Link to comment Share on other sites More sharing options...
SweetTea41 Posted March 22, 2022 Author Share Posted March 22, 2022 Did you reprogram the new ECU to talk nice with the rest of the system? You may need to update the VIN in the replacement ECU so it's recognized by the system, and you can start the car. The instrument cluster, BIU, and ECU all need the same VIN in their firmware; new ECU will have a different VIN and starting is likely disabled. It's a theft deterrent feature. You may have to do it yourself, not sure you'll find a dealer that will be willing to do it with your setup, but not sure. No, I simply plugged it in. I'd like to get it at least running before taking to my local tuning shop. How would I go about reprogramming the vin? Link to comment Share on other sites More sharing options...
omnicron Posted March 23, 2022 Share Posted March 23, 2022 I was able to swap ECU and relearn keys to ECU and BIU on 05 Legacy GT with a ~$50 programmer I bought years ago. I didn't have to program the "VIN" to the ECU. I use the SBB PRO2 V48.99 . They appear to be about $100 now. I have used it on STIs and other cars like Honda too. Link to comment Share on other sites More sharing options...
Infosecdad Posted March 23, 2022 Share Posted March 23, 2022 No, I simply plugged it in. I'd like to get it at least running before taking to my local tuning shop. How would I go about reprogramming the vin? There are a few options. The two most common I know about is to desolder and move the eeprom chip that holds the VIN number and move it to the replacement ECU. You can also use a chip clamp and some python scripts to read the VIN off the old eeprom chip and clone it to the replacement chip. Some info in this thread: https://legacygt.com/forums/showthread.php/clone-your-immobilizer-chip-replacement-ecm-ecu-279426.html The programmer might be able to do it as well, I'm assuming it does something similar because when the car is powered up it checks to make sure the VIN matches between the cluster, BIU, and ECU before allowing starting. Link to comment Share on other sites More sharing options...
SweetTea41 Posted March 25, 2022 Author Share Posted March 25, 2022 Update: Had a locksmith come over to program the ecm to my keys and she fired up and ran really smooth! Now all that needs to be done is fix one of the tires, emissions, registration, and a tune. Link to comment Share on other sites More sharing options...
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