Capacitor Help Needed
04-08-16, 08:55 PM
#16
Pit Crew
Thread Starter
My experience with electrolytic caps is that they swell when they go bad. Looking at the photo, I see some slight discoloration on the body of one of the caps in question, but it doesn't look like any of the three are swollen.
If there was water on the board when it was powered, you probably should see some evidence of corrosion at the leads of the parts wherever the water collected. And if the corrosion actually occurred, there should be corrosion products on the board which are deposited on the board during the corrosion process and as the water dries. I also do not see any evidence of water having been on the board near the caps based on the photos. But there is discoloration (rust colored) on the upper right corner of the board on the ground plane near the heat sink.
Can you take photos of the reverse side of the PCB? both a low magnification of the entire board and zoomed into that corner as well as the at the caps in question, and anywhere else you might see possible corrosion.
If there was water on the board when it was powered, you probably should see some evidence of corrosion at the leads of the parts wherever the water collected. And if the corrosion actually occurred, there should be corrosion products on the board which are deposited on the board during the corrosion process and as the water dries. I also do not see any evidence of water having been on the board near the caps based on the photos. But there is discoloration (rust colored) on the upper right corner of the board on the ground plane near the heat sink.
Can you take photos of the reverse side of the PCB? both a low magnification of the entire board and zoomed into that corner as well as the at the caps in question, and anywhere else you might see possible corrosion.
Thanks!
Last edited by PrisyCrisy; 03-18-19 at 01:34 PM.
04-08-16, 09:12 PM
#17
Pit Crew
Thread Starter
Salim,
I actually checked the relay and used the horn 12v just to make sure... Absolutely no difference. I could hear the relay box clicking when turning the car to the start position, but not cranking it. There was power to the box.
My check engine light has been on for awhile, because of a mechanic who replaced part of the muffler and then decided not to replace the bolts and flange near the O2 sensor (under the drivers seat). Instead he used 2 metal tie rods which caused my check engine light to remain on (an O2 sensor code) as well as the VSC light that also remained on. I was told the lights would stay on until the bolts and flange were back in and that it didn't matter, that my O2 sensor was fine. I still got 19-20 mpg.
With that said.... Not seeing the check engine light at all raised a flag for me... Which to me said, computer. So now, which part of that circuit board is bad... More digging to do in the morning!
I actually checked the relay and used the horn 12v just to make sure... Absolutely no difference. I could hear the relay box clicking when turning the car to the start position, but not cranking it. There was power to the box.
My check engine light has been on for awhile, because of a mechanic who replaced part of the muffler and then decided not to replace the bolts and flange near the O2 sensor (under the drivers seat). Instead he used 2 metal tie rods which caused my check engine light to remain on (an O2 sensor code) as well as the VSC light that also remained on. I was told the lights would stay on until the bolts and flange were back in and that it didn't matter, that my O2 sensor was fine. I still got 19-20 mpg.
With that said.... Not seeing the check engine light at all raised a flag for me... Which to me said, computer. So now, which part of that circuit board is bad... More digging to do in the morning!
04-11-16, 02:44 PM
#18
Pit Crew
Thread Starter
So... I picked up a magnifying glass and looked over the ECM front and back, carefully cleaned off any dust and looked for any swelling capacitors or rust or corrosion... None found. So I put the ECM back in the car.
I picked up a fuse tester and started going thru the fuses... Some are not working at all. In the engine compartment the headlights high and low beams #3, #4, #18, # 19, #20 ... Nothing, no power to those fuses, pulled fuses and replaced, nothing, circuit is dead. Inside the car all but one fuse is working #40 the starter fuse, swapped it out, nothing, checked the connections, nothing.
Car still cranks great, but no start.
Still no check engine light appearing
The security system light is not activated at all.
I checked it with the main flat key, just to see if it would reprogram.... Nope, no light, nothing.
I'm out of ideas.
I picked up a fuse tester and started going thru the fuses... Some are not working at all. In the engine compartment the headlights high and low beams #3, #4, #18, # 19, #20 ... Nothing, no power to those fuses, pulled fuses and replaced, nothing, circuit is dead. Inside the car all but one fuse is working #40 the starter fuse, swapped it out, nothing, checked the connections, nothing.
Car still cranks great, but no start.
Still no check engine light appearing
The security system light is not activated at all.
I checked it with the main flat key, just to see if it would reprogram.... Nope, no light, nothing.
I'm out of ideas.
04-11-16, 04:00 PM
#19
Moderator
Get hold of circuit diagram and trace.
It has to be 12v problem .. switched and or un-switched [switched -> by ignition]
Salim
It has to be 12v problem .. switched and or un-switched [switched -> by ignition]
Salim
04-12-16, 06:57 AM
#21
Moderator
hmm .. it should be wires to from each connector's name, location in each connector.
Salim
Salim
04-12-16, 09:56 AM
#22
Pit Crew
Thread Starter
http://askatech.com/AskATechLive/Aat...ack/TA2068.pdf
I don't own a broadcasting type tool to trace the power to find the short. Oh well.
04-12-16, 11:03 AM
#23
Moderator
I would trace the open ,, like why is there no B+ (12v). If 12v is missing on the other side of the fuse then first i would attempt by replacing the fuse. If the fuse pops, then you have a short. Once you establish a short in a brach then we get into the process of debugging it.
You have to pick one end .. the battery side or the destination side. Destination side would be the ECU.
The other option is to trace by hunch. Like start where you had water penetration.
Salim
You have to pick one end .. the battery side or the destination side. Destination side would be the ECU.
The other option is to trace by hunch. Like start where you had water penetration.
Salim
04-12-16, 11:16 AM
#24
Pit Crew
Thread Starter
I would trace the open ,, like why is there no B+ (12v). If 12v is missing on the other side of the fuse then first i would attempt by replacing the fuse. If the fuse pops, then you have a short. Once you establish a short in a brach then we get into the process of debugging it.
You have to pick one end .. the battery side or the destination side. Destination side would be the ECU.
The other option is to trace by hunch. Like start where you had water penetration.
Salim
You have to pick one end .. the battery side or the destination side. Destination side would be the ECU.
The other option is to trace by hunch. Like start where you had water penetration.
Salim
I'll look it up.
04-12-16, 01:44 PM
#25
Moderator
Check voltage on each side of the fuse.
They should match!
Trace the path on the schematic of how 12v gets to ecu.
Trace the presence of 12v on the vehicle as expected by the schematic.
Salim
They should match!
Trace the path on the schematic of how 12v gets to ecu.
Trace the presence of 12v on the vehicle as expected by the schematic.
Salim
05-25-16, 01:41 PM
#26
Pit Crew
Thread Starter
My experience with electrolytic caps is that they swell when they go bad. Looking at the photo, I see some slight discoloration on the body of one of the caps in question, but it doesn't look like any of the three are swollen.
If there was water on the board when it was powered, you probably should see some evidence of corrosion at the leads of the parts wherever the water collected. And if the corrosion actually occurred, there should be corrosion products on the board which are deposited on the board during the corrosion process and as the water dries. I also do not see any evidence of water having been on the board near the caps based on the photos. But there is discoloration (rust colored) on the upper right corner of the board on the ground plane near the heat sink.
Can you take photos of the reverse side of the PCB? both a low magnification of the entire board and zoomed into that corner as well as the at the caps in question, and anywhere else you might see possible corrosion.
If there was water on the board when it was powered, you probably should see some evidence of corrosion at the leads of the parts wherever the water collected. And if the corrosion actually occurred, there should be corrosion products on the board which are deposited on the board during the corrosion process and as the water dries. I also do not see any evidence of water having been on the board near the caps based on the photos. But there is discoloration (rust colored) on the upper right corner of the board on the ground plane near the heat sink.
Can you take photos of the reverse side of the PCB? both a low magnification of the entire board and zoomed into that corner as well as the at the caps in question, and anywhere else you might see possible corrosion.
Is that rust near R226 ?
Rust/ corrosion near connections ?
Don't see rust near the ground.
05-25-16, 01:54 PM
#27
Instructor
You are one very ambitious DIYer! Good luck! Let us know if there is anything we can do by inspecting our running vehicles in search of some clue as to why yours isn't.
05-25-16, 03:50 PM
#28
Pit Crew
Thread Starter
So thank you... It means a lot.... NOW.... IF I COULD ONLY FIGURE THIS OUT! Too bad I'm not living in an episode of I dream of Jeanie!!! Lol. POOF!
Well... I can dream!! Hahhaaa
Keep the suggestions coming!
05-25-16, 05:14 PM
#29
Moderator
I would suggest that you look for a replacement ECU. Make sure you get atleast one master key.
Salim.
Salim.
05-25-16, 06:23 PM
#30
Prizy,
That brown material looks like residual flux residue that was left on the solder after the board was cleaned.
I don't see any evidence of corrosion in those close-ups.
Lexmus
That brown material looks like residual flux residue that was left on the solder after the board was cleaned.
I don't see any evidence of corrosion in those close-ups.
Lexmus