52 code 1988 supra

Bru · 05-30-2018, 03:43 AM

Code 52 is knock sensor. A Turbo car has 2 of them under the intake manifold on the block. A non-turbo car has one. A common problem is that the wiring harness for a knock sensors gets grounded. With my previous wiring harness I had to bypass the harness and run a separate wire from the knock sensor to the computer under the glove box shield. The way to test for this is to: unplug the sensor and run a test wire from the plug through a ohmmeter then to the plug on the of the harness that plugs into the computer (With the computer module unplugged). Look for an open or ground to the body. If there is continuity in the wire and no open or ground then check the other sensor harness the same way. Here is a link to a online supra manual that will give you the layout of the plugs that go into the computer.
On another note, check your vacuum lines to make sure nothing's unplugged. The routing for that is underneath the hood on a picture.

http://www.cygnusx1.net/supra/techtips.aspx

http://www.cygnusx1.net/supra/Librar...aspx?S=FI&P=50

KNK1 and KNK2 are in the middle plug.

I can't remember which one is #1 the front or the back. Is unlikely both are grounded. It should become apparent when doing the testing of both.
The plug comes off with a squeeze and I think its green. Be careful not to brake the sensor. They are expensive. I broke the one back by the starter with a socket extension when replacing the starter.

05-30-2018, 03:43 AM	#2
Bru Bone Stock w Upgrades ;-) Join Date: Apr 2010 Location: Tampa Bay Posts: 210	Code 52 is knock sensor. A Turbo car has 2 of them under the intake manifold on the block. A non-turbo car has one. A common problem is that the wiring harness for a knock sensors gets grounded. With my previous wiring harness I had to bypass the harness and run a separate wire from the knock sensor to the computer under the glove box shield. The way to test for this is to: unplug the sensor and run a test wire from the plug through a ohmmeter then to the plug on the of the harness that plugs into the computer (With the computer module unplugged). Look for an open or ground to the body. If there is continuity in the wire and no open or ground then check the other sensor harness the same way. Here is a link to a online supra manual that will give you the layout of the plugs that go into the computer. On another note, check your vacuum lines to make sure nothing's unplugged. The routing for that is underneath the hood on a picture. http://www.cygnusx1.net/supra/techtips.aspx http://www.cygnusx1.net/supra/Librar...aspx?S=FI&P=50 KNK1 and KNK2 are in the middle plug. I can't remember which one is #1 the front or the back. Is unlikely both are grounded. It should become apparent when doing the testing of both. The plug comes off with a squeeze and I think its green. Be careful not to brake the sensor. They are expensive. I broke the one back by the starter with a socket extension when replacing the starter. Attached Thumbnails Last edited by Bru; 05-30-2018 at 04:42 AM.