Code 52 doesn’t leave me alone
- Thread starter jony89
- Start date
I haven't had the time to play with the many combinations of items that could be wrong, nor do I want to buy two new sensors when something else could be at fault (the wiring or the ecu). The biggest issue is a can't repeat the symptoms since I swapped the new sensor into the front spot.
No single "best" solution has been handed to me... I have heard you and many others state that the knock sensors are year specific, but 3p141592654 doesn't think it matters. He knows more about our ECUs than possibly anyone on this board. Either way, I am just trying to gather information so that I can figure out what the best diagnostic protocol is. If I had an O-Scope or access to one I would use it. It doesn't sound like can use a DMM without knowing what voltage the ecu needs to see, which it seems no one really knows the knock program that the Toyota TCCS uses.
I really do appreciate your input as well as all the other helpful replies. Hopefully I will have time this weekend that I can do a continuity test on my wiring harness and swap some sensors around. I plan on using that middle KS bung as you had noted. Thanks for that tip BTW.
If I have missed something, please let me know.
No single "best" solution has been handed to me... I have heard you and many others state that the knock sensors are year specific, but 3p141592654 doesn't think it matters. He knows more about our ECUs than possibly anyone on this board. Either way, I am just trying to gather information so that I can figure out what the best diagnostic protocol is. If I had an O-Scope or access to one I would use it. It doesn't sound like can use a DMM without knowing what voltage the ecu needs to see, which it seems no one really knows the knock program that the Toyota TCCS uses.
I really do appreciate your input as well as all the other helpful replies. Hopefully I will have time this weekend that I can do a continuity test on my wiring harness and swap some sensors around. I plan on using that middle KS bung as you had noted. Thanks for that tip BTW.
If I have missed something, please let me know.
The ECU is rarely at fault for a code 52, the wiring can be checked with an ohm meter and that leaves the KS itself at the end.
If you've got some other mk3 buddies around you, swap the KS with a good known KS, does it go away? Can you swap ECU's? If you touch the KS wire then touch a chassis ground, what's your reading say?
If you've got some other mk3 buddies around you, swap the KS with a good known KS, does it go away? Can you swap ECU's? If you touch the KS wire then touch a chassis ground, what's your reading say?
Yah, I plan to test the wiring this weekend for continuity and to make sure I don't have some of the shielding touching the main wire anywhere. Then I am going to start swapping sensors and hopefully that fixes my issues. I'll report back when I get some of these test done.
Thanks for the help guys.
Thanks for the help guys.
I figured I would update this as it appears my problem is fixed now 
Two weekends ago I went ahead and used my DMM to test my harness. No continuity was present between the lead wires and ground, and I was getting 1.6V with the EFI fuse in and when the ECU has power. I went ahead and installed my original front knock sensor into the center hole and connected it to the KS1 (my front) lead to see if I could reproduce the symptoms I was having before I started messing with all this. I re-tightened all the sensors and I drove it around for that week and no CEL
This past weekend I went ahead and removed the new-to-me KS out of the front bung and reinstalled my original gray plug KS into the front bung and reconnected it. So far no CEL, hopefully it stays that way.
So the only thing that I can think of that was causing the intermittent CEL would be that both the front and rear sensors were fairly loose, the rear sensor started to spin when I was trying to wiggle the connector off... I re-tightened the rear when I tested the harness, snugging it up before reconnecting the KS lead.
I am guessing without being torqued down, the KS gets an intermittent ground, correct me if I am wrong but I believe the case of the KS is the ground?
Thanks for all the help while I sorted through this problem. It always helps to talk things through, sorry for those who were annoyed with the incessant questions.
Have a great week!
Two weekends ago I went ahead and used my DMM to test my harness. No continuity was present between the lead wires and ground, and I was getting 1.6V with the EFI fuse in and when the ECU has power. I went ahead and installed my original front knock sensor into the center hole and connected it to the KS1 (my front) lead to see if I could reproduce the symptoms I was having before I started messing with all this. I re-tightened all the sensors and I drove it around for that week and no CEL
This past weekend I went ahead and removed the new-to-me KS out of the front bung and reinstalled my original gray plug KS into the front bung and reconnected it. So far no CEL, hopefully it stays that way.
So the only thing that I can think of that was causing the intermittent CEL would be that both the front and rear sensors were fairly loose, the rear sensor started to spin when I was trying to wiggle the connector off... I re-tightened the rear when I tested the harness, snugging it up before reconnecting the KS lead.
I am guessing without being torqued down, the KS gets an intermittent ground, correct me if I am wrong but I believe the case of the KS is the ground?
Thanks for all the help while I sorted through this problem. It always helps to talk things through, sorry for those who were annoyed with the incessant questions.
Have a great week!
It's not just the ground that is the biggest deal, with it not being tight the mV was not being produced for the KS to even work. The KS works off the actual frequency going through the block, when it starts knocking the KS picks up that frequency and starts producing mV.