taskz Posted September 15, 2018 Share Posted September 15, 2018 Hi, I recently replaced the heater core in my 2001 Forester L. Everything basically went to plan, but I'm having some issues. 1. There are several trouble codes: P0500 Vehicle speed sensor malfunction P1540 Vehicle speed sensor malfunction 2 P1591 Neutral position switch circuit low input P1518 Starter switch circuit low input P0512 Starter switch circuit high input P0316 Misfire Occurred in the First 1000 Engine Revolutions 2. The gauge cluster is acting strange. Normally the lights behave but once I turn on the headlights only some of the gauges are lit and the backlights for the LCD displays turn off. I've inspected the wiring a bunch of times. I went to a salvage yard and tore into the dashes of 3 foresters to make some detailed comparisons. Took a ton of pictures. Long story short, I'm pretty sure the wiring in my Forester was properly connected. I checked the fuses and they are fine. There are two connectors I can't seem to find mates for. There's a single black wire that attaches to something somewhere around the cigarette lighter I can't find a mate for. In the same location there's a connector with 3 prongs in the same area I can't find a connection to. I have the cig lighter and whatnot properly wired up, though. I'm pretty stumped and any advice is appreciated. The service manual I've been reading is clear as mud as far where components are in the car that I can test. Any guidance with any of this is massively appreciated. The car otherwise runs and drives seemingly fine. TIA Quote Link to comment Share on other sites More sharing options...
montana tom Posted September 16, 2018 Share Posted September 16, 2018 You had the entire dash off to do a heater core. Think about grounds ... was there one deep in there ? Been awhile since I did that job ,but I seem to remember at least one serious ground under there. Quote Link to comment Share on other sites More sharing options...
taskz Posted September 16, 2018 Author Share Posted September 16, 2018 I don't remember seeing any real major grounds except for a couple that bolted to the frame near the airbag controller (not sure of the term) but I'll definitely take a closer look. It's been a few years since I did anything more on a car than change the oil and I'm probably in over my head a little. Definitely a big job and electrical isn't my strong suit. Thanks for you reply! 1 Quote Link to comment Share on other sites More sharing options...
montana tom Posted September 16, 2018 Share Posted September 16, 2018 Other thing is, inspect every connector. With your dash being iffy the large plug on the back of the gauge cluster is suspect. I'm sure you have already checked that they are plugged and tight but you may need to look for wires that backed out from connector when you plugged in. Problems like this are very frustrating, huge job most of it covered up now.... It worked before you started soooo its something that happened while you were in there... If you have a buddy who knows cars, use another pair of eyes ... sometimes you just don't see things after you have stared at it for hours on end. 1 Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted September 16, 2018 Share Posted September 16, 2018 Other than the misfire, that's probably all related to the transmission harness. You probably forgot a ground, or forgot to plug something in. Did you take pictures or film it along the way? GD Quote Link to comment Share on other sites More sharing options...
taskz Posted September 17, 2018 Author Share Posted September 17, 2018 11 hours ago, montana tom said: Other thing is, inspect every connector. With your dash being iffy the large plug on the back of the gauge cluster is suspect. I'm sure you have already checked that they are plugged and tight but you may need to look for wires that backed out from connector when you plugged in. Problems like this are very frustrating, huge job most of it covered up now.... It worked before you started soooo its something that happened while you were in there... If you have a buddy who knows cars, use another pair of eyes ... sometimes you just don't see things after you have stared at it for hours on end. I actually plan to do just that tomorrow. I checked for any loose grounds. That all looks good. I have a son in law whose studying to be a certified tech and I'll definitely bring him in. When I was replacing the heater core, I carefully pulled out the strut that runs across under the dash, on the passenger side, just enough to get the heater box out. I tried to remove the fuse box on the driver side but I couldn't find a way to uncouple the strut from the fuse box. . There wasn't a predefined procedure in the manual I'm using. Basically said "Remove the strut". Couldn't find any info on the internet on how. 11 hours ago, GeneralDisorder said: Other than the misfire, that's probably all related to the transmission harness. You probably forgot a ground, or forgot to plug something in. Did you take pictures or film it along the way? GD Yup. Took a ton of pics on disassembly and when I went to the salvage yard to compare the wiring. . I'm 100% certain everything is connected right. Like I told montana tom, I'll bring in a fresh pair of eyes tomorrow and see what he thinks. I'm also going to look for bad connections (fun) and I'll make a note to look at the transmission harness first. Thanks for your help, folks. I'll keep you posted Quote Link to comment Share on other sites More sharing options...
taskz Posted September 18, 2018 Author Share Posted September 18, 2018 Well, my son in law and I spent the day going over the wiring; fault checking and inspecting the connectors. Everything is fine there. Nothing out of place, broken or otherwise bad. We fixed the gauge cluster issue. Turns out some components burnt out and I'm going to the salvage yard tomorrow to get a donor one. We also tested (again) the sensors associated with the codes and they were fine. The computer is still throwing the same codes. I'm thinking my original theory is probably correct. When I reconnected the battery there must have been some sort of power surge. I'm trying to figure out the next step. Should I try swapping the ECM and/or TCM? Is there something else I'm not considering? Quote Link to comment Share on other sites More sharing options...
taskz Posted September 21, 2018 Author Share Posted September 21, 2018 (edited) I put the car back together earlier this evening and I'm just going to take it to the mechanic. Same trouble codes, same issue with the gauge cluster after replacing parts of it, Tried swapping the TCM as an ECM isn't available in my area unless I want to buy a brand new one and have the dealership program it. disconnected and reconnected all the connectors, tested them for continuity, etc, etc. Tested all the relays we could see under the dash, on and on. I agree it's probably an issue with the ground and/or the wiring and we just can't see it. I'd keep plugging away but it's one of my parent's cars, not mine and they kinda want it back. I appreciate the help, though. A few days ago I was given a free 2000 Impreza Outback as a project/learning experience and once I get going on that I'm sure I'll be back with more craziness. Edited September 21, 2018 by taskz 1 Quote Link to comment Share on other sites More sharing options...
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