Code 52 problems, Please help!

blue_spra

New Member
Apr 6, 2005
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Pasco, WA
For a few months now my ecu has been throwing code 52. I have replaced both knock sensors and reset the ecu and no good. Then I tried running new wire from each sensor to the ecu, then i reset the ecu and still no good. The engine light doesn't come on right away when i start the car, it comes on when i start driving and stays on until i turn off the car. What should be my next move? I want my supra back.
 

steve_mk3

Supramania Contributor
Mar 30, 2005
334
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middletown, NJ
Code 52 is NOT caused by knock.
It is caused by the ECU not recieving the correct signal from the knock sensors.
There are a few possible causes.
1- bad knock sensor
2- bad wireing
3- bad ecu

So you have replaced the knock sensors, so that's one down

It is realy rare that the ECU goes bad

It is a common problem that the wiring is bad.

Do a search on Knock sensor and read about the rewire.
I think there are some members that make a sensor rewiring kit.
 

jetjock

creepy-ass cracka
Jul 11, 2005
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Redacted per Title 18 USC Section 798
At last. Well said too. Prompts me to expand a bit on what I mentioned above:

Knock codes (52 and 53) aren't set in memory until the engine has been run for a certain amount of time and above a certain rpm. In addition knock faults won't shut off the MIL if the condition that caused them should clear. The light will stay on until one IGN key cycle occurs. I'd have to check but if I recall correctly these are the only faults to do this.
 

shaeff

Kurt is FTMFW x2!!!!
Staff member
Super Moderator
Mar 30, 2005
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Around
to add a bit more- code 52 NEVER means that you have any sort of knock.

code 52 is registered in the ECU ONLY if there is a fault in the electical circuit between the ECU and the knock sensors themselves (both including the KS's and the ECU).

-shaeff
 

blue_spra

New Member
Apr 6, 2005
12
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Pasco, WA
The knock sensor is a seemingly simple one wire sensor. I already ran a new wire from each sensor to the ECU and still CEL is on. So you think the ECU is the problem?

steve_mk3 said:
Code 52 is NOT caused by knock.
It is caused by the ECU not recieving the correct signal from the knock sensors.
There are a few possible causes.
1- bad knock sensor
2- bad wireing
3- bad ecu

So you have replaced the knock sensors, so that's one down

It is realy rare that the ECU goes bad

It is a common problem that the wiring is bad.

Do a search on Knock sensor and read about the rewire.
I think there are some members that make a sensor rewiring kit.
 

steve_mk3

Supramania Contributor
Mar 30, 2005
334
5
18
62
middletown, NJ
It is not a simple one wire connector.
It is a shielded connector.
Right now you have a wiring problem.


The ECU is not looking for voltage from the knock sensore, it is looking for a certain frequency.

you need to replace the wireing correctly and it must be grounded properly.

This has all been covered, and I have written this up befor. please search-

Also you may wish to pm Shaeff?
 

blue_spra

New Member
Apr 6, 2005
12
0
0
Pasco, WA
YES!!! I finally have my supra back. To elaborate on what i saw when i was in there, at first all a could see was the signal wire to the ecu. I had to trace them up the harness a bit to find the ground shield looping back into the harness. I cut the loop and tested continuity to ground on either side of the cut. One side showed continuity and the other did not. I took the end that did not show ground on each sensor and grounded them, bingo, im boosting again.