Error code 52. What's next

[THR4SHER007]

So, before lockdown I had taken my 91 G LTD to an auto electrician to re wire my horn away from the center of the steering wheel. When I picked my car up I started driving down the road and my check engine light came on. The next day I took it to my mechanic and he scanned for codes, he found a few, then cleared the codes, which only code 52 remained. Since then I have replaced the knock sensor itself but to no avail, the code still appears. The code appears to only come on above 2500 rpm under load, but never when not in gear. I'm just wondering what needs to be done next.

Thanks

[GDII]

Maybe wiring is a problem. It's a shielded circuit so a little complicated. Seems lots of the USA guys have possible wiring problems with this circuit on the 3SGTE but never heard of it in a JDM G-LIMITED before.
Or for some reason you have very bad fuel or the mechanical timing is out on the distributor. Too advanced.

[Jabeo]

I had this exact problem not too long ago that i battled with, and code 52 will only show if the ecu isnt receving a signal from the knock sensor, so it doesn't necessarily mean a knock event which is good. i ended up sourcing 2 knock sensors, one from a 3sge or 5sge i cant remember and one from a 2jz. if i remember correctly i think one gave me the same error and the other worked just fine, otherwise they were both fine.

The only other thing it could be is the wire to the ecu its self, so you could check continuity from the knock sensor plug pin to the the ecu pin using a multimeter which might help you rule that out. Take the ecu cover off and the pcb will tell you what pin is for the knock sensor. if its bad the wire might need to be replaced however just double check the ohm resistance on the sensor you got if its used. could be that yet another sensor might sort it

[Reubenh]

I know this is an oldish thread but I have some knowledge here.

It's important to use a knock sensor from an engine with the same BORE SIZE.

When knock happens, the pressure waves bouncing make a frequency based on the size of the bore.

You could plug a 4age knock sensor in for example but the knock sensing will become much less sensitive than it once was. Sure you won't get a fault code and it won't pull timing but the problem is you will blow the engine up.

Don't use a 5sfe sensor in a 3sgte for example. You can use a 3sge sensor on a 3sgte in theory but there may be some other differences that I don't know about.


Also... The ECUs on all Toyotas of the time are prone to failing from solder cracks and capacitors passing DC or literally leaking onto the PCB and breaking tracks from the acidic electrolyte.

[THR4SHER007]

The thread may be a bit old but I still have the problem. I purchased an aftermarket knock sensor for Toyota, that may be a problem. My mechanic is going to send it to a Dyno to check for engine knock, as it isn't making any odd sounds loud enough to hear. I may look at a used genuine knock sensor from a wrecked 3sge. I've had an auto electrician look at the wiring and they said everything is working as intended but the CEL still comes up but at 3250 RPM now.

[Reubenh]

I probably have a 3sge knock sensor somewhere if you want it.

I'd highly recommend opening up the ECU and checking under the capacitors for damage to the board.

What are the numbers (should be 89661-*******)

I may even have the correct ECU if you want it

[THR4SHER007]

I probably have a 3sge knock sensor somewhere if you want it.

I'd highly recommend opening up the ECU and checking under the capacitors for damage to the board.

What are the numbers (should be 89661-*******)

I may even have the correct ECU if you want it

If you could find a 3SGE knock sensor I would gladly take it.

I will take a look at my ECU and get back to you on that one.