Did I fry my ECU? So pissed at myself
03-01-17, 10:39 PM
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Did I fry my ECU? So pissed at myself
Hey Guys, I am a newbie poster but have used this for information several times. I may have made a huge mistake and cost myself thousands of dollars but hopefully there is a more simple solution.
I own a 2004 GS300 and the battery had been dying randomly if I sat in the car for a few minutes after turning it off. Nothing was on to my knowledge so that doesn't make much sense to me but alas that is not really my issue here.
The issue is that a few days ago my car was dead when I went to start it and I had to borrow my roommates car to jump. I had not used this particular car(mercedes) to jump before so I didn't know the battery was in the trunk. When I finally figured out where the battery was it was a ***** to get to as he had so much crap in there. I couldn't see the nodes and had to go by feel. Very stupid but I was pretty sure I felt the positive and negative symbol and connected the cables to that by feel. Then went to my battery. As soon as I connected the negative side after the positive the car horn started blaring. This is new. So I went back and checked the cables on the mercedes and I swear again that I had them connected correctly negative to negative P to P but could be wrong. ANyway i connected it back to my battery and the horn started blaring again.. I decided to go try to start the car anyway. (Huge mistake i'm sure) but it almost turned over. But after that it never even tried again. I gave up and tried the next morning. Nothing. Not even a hint of electricity running throuhg the car. So I figured I blew the battery. Replaced the battery with a brand new one later that day. Still nothing, not even the flashing key light came on. The car was a ghost.. Got some advice and checked the alternator fuse. IT was blown! excellent. This should fix it. After an incredible pain in the *** to get the fuse out I replaced it with a new one and bam! lights! SO happy. FIgured the car would start right up. Nope. not even a click. The fuel pump turns on but not a click from the starter or the starter relay. I went to oreilys and got a new starter relay. That is where they told me it was possible I blew the ECU and that it could be incredibly expensive. Fuuuuuuuuuuuuuhk
the Starter relay fuse is getting power. I checked that with the fuse tester and we know the relay is good because it too is brand new. Is there anything else I can try before towing the car to the dealership and spending thousands to fix? I know it is eternally stupid to connect the wrong cables while jumping a car but still. Should it result in this type of catastrophe?
Last little tidbit is that my key does not work for the doors. Only manually. I am unable to reprogram the key using online instructions to do so. The car does get into programming mode "unlocks after pulling out of ignition" after 5 "back and forths" and then entering the ignition but it wont actually program. maybe that is preventing the car from starting?. At this point I will try anything before taking it to the dealership. Appreciate any and all advice. Thanks a ton guys.
-Adam
I own a 2004 GS300 and the battery had been dying randomly if I sat in the car for a few minutes after turning it off. Nothing was on to my knowledge so that doesn't make much sense to me but alas that is not really my issue here.
The issue is that a few days ago my car was dead when I went to start it and I had to borrow my roommates car to jump. I had not used this particular car(mercedes) to jump before so I didn't know the battery was in the trunk. When I finally figured out where the battery was it was a ***** to get to as he had so much crap in there. I couldn't see the nodes and had to go by feel. Very stupid but I was pretty sure I felt the positive and negative symbol and connected the cables to that by feel. Then went to my battery. As soon as I connected the negative side after the positive the car horn started blaring. This is new. So I went back and checked the cables on the mercedes and I swear again that I had them connected correctly negative to negative P to P but could be wrong. ANyway i connected it back to my battery and the horn started blaring again.. I decided to go try to start the car anyway. (Huge mistake i'm sure) but it almost turned over. But after that it never even tried again. I gave up and tried the next morning. Nothing. Not even a hint of electricity running throuhg the car. So I figured I blew the battery. Replaced the battery with a brand new one later that day. Still nothing, not even the flashing key light came on. The car was a ghost.. Got some advice and checked the alternator fuse. IT was blown! excellent. This should fix it. After an incredible pain in the *** to get the fuse out I replaced it with a new one and bam! lights! SO happy. FIgured the car would start right up. Nope. not even a click. The fuel pump turns on but not a click from the starter or the starter relay. I went to oreilys and got a new starter relay. That is where they told me it was possible I blew the ECU and that it could be incredibly expensive. Fuuuuuuuuuuuuuhk
the Starter relay fuse is getting power. I checked that with the fuse tester and we know the relay is good because it too is brand new. Is there anything else I can try before towing the car to the dealership and spending thousands to fix? I know it is eternally stupid to connect the wrong cables while jumping a car but still. Should it result in this type of catastrophe?
Last little tidbit is that my key does not work for the doors. Only manually. I am unable to reprogram the key using online instructions to do so. The car does get into programming mode "unlocks after pulling out of ignition" after 5 "back and forths" and then entering the ignition but it wont actually program. maybe that is preventing the car from starting?. At this point I will try anything before taking it to the dealership. Appreciate any and all advice. Thanks a ton guys.
-Adam
03-02-17, 06:00 AM
#2
If it's any consolation, I did the same thing thirty years ago on my first car, a 69 Plymouth Valiant.
Battery started hissing and I just stepped back helpless. Luckily, the car started after replacing the battery and positive wire. Stil, I'm traumatized to this day and check pos/negative ten times before I connect any battery
Battery started hissing and I just stepped back helpless. Luckily, the car started after replacing the battery and positive wire. Stil, I'm traumatized to this day and check pos/negative ten times before I connect any battery
03-02-17, 09:17 AM
#3
Lexus Test Driver
I'm not sure on the GS but I connected the wrong battery terminals once on my gf's RAV4 and it only blew the main fuse....it was like $20 or so. You might want to have the dealer look at it and reprogram your keys while you're at it. I don't think it would be in the thousands of dollars; many people have connected the battery terminal the wrong way and lived to tell about it
03-03-17, 11:22 AM
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Does the ECU power up? and did you blow the starter fuse? on my 2000 GS400 i just recently throught i fried my ECU when an o2 sensor heater wire arced onto the block during some exhaust work. I blew the EFI fuse under the hood. My symptoms were a crank, no start, and the check engine light did not illuminate during bulb check (few seconds after key is turned on). If you blew a fuse to the starter, it might be refusing to crank. Try checking the starter fuse, on page 262 of your owners manual should be a fuse layout. then if it begins to crank and still doesnt start, try the EFI fuse.
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