P3025, changed Knock Sensors and Harness, still throwing P3025???
#1
Lead Lap
Thread Starter
P3025, changed Knock Sensors and Harness, still throwing P3025???
So I was asked by a member ( a pro-wrench ) to post a pic of the repair I made to correct the re-curring P3025 even after all known repairs were made.
Some of you may know the story but here it is just for the new guys.
I was working on the transmission, required me to drop the trans and hold the engine up. DING DING DING, you should always do this properly. I lost my chains so I sued nylon straps, doh
So after the transmission repair, I hooked everything up and 100 miles later CEL, WTF?
The dreaded P3025, Ah poop. Okay, went to the junk yard and found two new old sensors off of a dry engine, went to Oriely's got a life time guaranteed Harness and Toyota Bypass hose.
Glad I did this because harness was toast. It crumbled in my hands on both ends. The old sensors tested fine per manual but I swapped with better conditioned (visual and resistance tested only) new old sensors, didn't hurt to do it since I have her apart. By pass was toast too. Man it gets hot there.
All back together, all seemed fine then CEL, WTF?
Re-checked everything. All good but did notice the aftermarket connector was not fully seated because it's connector was fatter than the OEM, used di-electric grease and snapped right in. CEL reset.
2 days later CEL, oh come on!
I was looking for an ECU, then had a brain fart. Line 3 above. What if the harness on the ECU side was compromised due to the sloppy engine hanging I did???
Off to the junkyard, looked for a pliable, not so brittle Harness coming out of the ECU side. Cut as far back as possible. Brought it home upon splicing. I noticed the original wire was exposed with green/black corrosion. DING DING DING. The harness pull was the final straw that did it in but it appeared to be on it's way out due to the corrosion making a weak signal and throwing the false readings.
Carefully spliced the new old ECU side harness on paying close attention to the insulated signal wire ( most important ) liken to an oxygen sensor wire. I also added heat shrink and a shroud with electrical tape to protect it further against heat and oil.
1000+ miles later no CEL FIXED.
Here is the pic:
Some of you may know the story but here it is just for the new guys.
I was working on the transmission, required me to drop the trans and hold the engine up. DING DING DING, you should always do this properly. I lost my chains so I sued nylon straps, doh
So after the transmission repair, I hooked everything up and 100 miles later CEL, WTF?
The dreaded P3025, Ah poop. Okay, went to the junk yard and found two new old sensors off of a dry engine, went to Oriely's got a life time guaranteed Harness and Toyota Bypass hose.
Glad I did this because harness was toast. It crumbled in my hands on both ends. The old sensors tested fine per manual but I swapped with better conditioned (visual and resistance tested only) new old sensors, didn't hurt to do it since I have her apart. By pass was toast too. Man it gets hot there.
All back together, all seemed fine then CEL, WTF?
Re-checked everything. All good but did notice the aftermarket connector was not fully seated because it's connector was fatter than the OEM, used di-electric grease and snapped right in. CEL reset.
2 days later CEL, oh come on!
I was looking for an ECU, then had a brain fart. Line 3 above. What if the harness on the ECU side was compromised due to the sloppy engine hanging I did???
Off to the junkyard, looked for a pliable, not so brittle Harness coming out of the ECU side. Cut as far back as possible. Brought it home upon splicing. I noticed the original wire was exposed with green/black corrosion. DING DING DING. The harness pull was the final straw that did it in but it appeared to be on it's way out due to the corrosion making a weak signal and throwing the false readings.
Carefully spliced the new old ECU side harness on paying close attention to the insulated signal wire ( most important ) liken to an oxygen sensor wire. I also added heat shrink and a shroud with electrical tape to protect it further against heat and oil.
1000+ miles later no CEL FIXED.
Here is the pic:
#2
Lead Lap
Thread Starter
Here are the ECU side harness connector in question:
The one on the right is my old corroded one ( and this was after I tried to clean it ):
Left is an additional spare I found, most if not all the inner connectors were all yellowed and corroded, this and the one I have on the car were still OEM white with little to no corrosion.
The red clad wire is the one I was very careful with when splicing.
The one on the right is my old corroded one ( and this was after I tried to clean it ):
Left is an additional spare I found, most if not all the inner connectors were all yellowed and corroded, this and the one I have on the car were still OEM white with little to no corrosion.
The red clad wire is the one I was very careful with when splicing.
Last edited by DRACO A5OG; 05-25-16 at 12:56 PM.
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