Code 52 knock sensor
06-05-2018, 04:39 PM
#2
Registered User
We are going to need more information and a better description of what you have done. Punctuation makes reading easier.
First off, what engine do you have?
What have you tested and checked? Describe everything you have done so far, so we can "see" where you are at in the diagnosis.
RAD4Runner, our resident electrical guru always says:
Not coincidentally, code 52 is often the cause of a bad knock sensor wiring "pig tail".
First off, what engine do you have?
What have you tested and checked? Describe everything you have done so far, so we can "see" where you are at in the diagnosis.
RAD4Runner, our resident electrical guru always says:
A problem well-stated is almost solved. A picture paints a thousand words.
Next only to our senses, the multi-meter is the most important electrical diagnostic tool. Invest $6 at Harbor Freight and save money and time.
Toyota components are (almost) bullet-proof. Issues often arise from poor wiring, assembly and/or maintenance. Suspect those first.
Next only to our senses, the multi-meter is the most important electrical diagnostic tool. Invest $6 at Harbor Freight and save money and time.
Toyota components are (almost) bullet-proof. Issues often arise from poor wiring, assembly and/or maintenance. Suspect those first.
06-05-2018, 06:57 PM
#3
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Code 52 knock sensor
It's a 1991 Toyota 4runner 3.0 engine blew head gaskets, bought new rebuilt long block New knock sensor and harness under intake didn't have problems before put New motor in fired up and drove down road engine light comes on pull code 52 if you shut off engine and restart light goes off and down the road again it comes on in about 2 miles sometimes 1 mile or 4or 5 keep resetting, sometimes after reset the motor runs great like it never did before then turns into a dog again looked at all wires looks to be in good shape at plug also, tried some other thing like mounting outside that didnt work tried capacitors no work its a nice car im first owner in very good condition i need help guys thanks for any input I still need HELP PLEASE
Last edited by Red4x4; 06-07-2018 at 08:22 PM.
06-06-2018, 11:26 AM
#4
code 52 can be a real bear to solve. i'm chasing it myself on the '88 3.0 auto. i also replaced both the sensor and the short pigtail with brand-new toyota-sourced parts, yet still get the code 52 upon warm up and driving above 1500 rpm. continuity to the ecu verified for both the sensor wire and the shield wire. even swapped a spare ecu. makes no difference.
06-06-2018, 10:46 PM
#5
code 52 can be a real bear to solve. i'm chasing it myself on the '88 3.0 auto. i also replaced both the sensor and the short pigtail with brand-new toyota-sourced parts, yet still get the code 52 upon warm up and driving above 1500 rpm. continuity to the ecu verified for both the sensor wire and the shield wire. even swapped a spare ecu. makes no difference.
06-07-2018, 02:47 AM
#6
I saw your post when you bought the ‘88 3.0 and was going to ask you about the complementary code 52 package. I didn’t want to jinx you so I didn’t ask. I’ve done the same-new sensor, new wiring, replacement remanufactured ECU. The code still makes its appearance when it wants to. I don’t think I’m going to chase it again for a while. I get about 16 MPG even with the code(manual trans) and the truck runs well, with plenty of power. I can cruise at 70MPH easily, no lumpy idle or anything.
i did some continuity tests on the ecu pins, and found that the KNK pin has contiuity with E11, on both ecus. i have nothing else to compare to, and haven't located a source for more information. i do have the '88 3vze fsm.
Last edited by wallytoo; 06-07-2018 at 02:51 AM.
06-07-2018, 05:10 AM
#7
I just went through this with my 4Runner. I bought a long block that had a new Toyota knock sensor and harness installed on it. When I got it running again I had a code 52. I checked continuity and resistance on the signal wire and it was fine. I had saved my old knock sensor and so I tested it on my bench vice by tapping a piece of sheet metal, installing the knock sensor and then tapping on the vice with a hammer. I used my multimeter on mv Ac depending on how hard I hit the vice I got between .150-.500 mv. I then did the same test with my old harness installed and got the same values. I then installed the sheet metal in place of the rear engine hoist hook on the driver side. I unplugged my harness from the stock location and plugged into the one on sheet metal. Code was gone. I told the engine builder what I did and he replaced the knock sensor and harness again under warranty. When I picked it up I showed him how I bench tested it. The bad brand new sensor was only putting out .050 mv at the most. It did work but it wasn't enough for the computer to notice. I haven't had any issues since.
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06-08-2018, 11:21 PM
#8
Registered User
I had this problem after I recently put another 3.0 in my pickup. Known working sensor and new pigtail, got code 52 after driving for a couple blocks. Turned out my the plug where the wiring harness plugs into the pigtail had broken under the orange little grommet. I figured it out by sticking a long flat head under the plenum and moving the connector around it got rid of the check engine light temporarily. I was able to re crimp the wire in the connector and re solder the shield wire and it got rid of code 52. It was kind of a delicate process pulling the orange grommet out and getting it all back together, but the check engine light has been off for a couple months now.
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