check engine light: code 52 and 55 - Toyota Nation Forum : Toyota Car and Truck Forums

ryuji16 · 09-23-2006, 04:03 PM

(for my 92 gen3 3vz-fe)...

according to haynes:

code 52 = open or short circuit in knock sensor circuit. also suggests potential ecm problem.
code 55 = problem with knock control system, and says its an ecm problem.

is this necessary to fix? could it mean that i might need new knock sensors, or maybe a problem with the ecm? what do you all think could have caused this... i recently got new spark plugs installed about a month ago, and ive had the light on for about 2-3 weeks. also had cap/rotor and wires done at the same time.

the CEL doesnt affect how the car runs though.

haynes says i need remove the intake plenum to get to the knock sensors. im not sure i wanna get into that if i dont have to.

what do you guys think?

Axel Kain · 09-24-2006, 01:21 AM

...sadly sounds more like the dealer needs to reprogram, or replace the ecm.

but dont quote me

***toyomoho*** · 09-25-2006, 04:40 PM

The knock sensor can be tested with an ohmmeter. It should not have electrical continuity.

ryuji16 · 09-26-2006, 04:06 PM

thanks for providing the info guys. i was wondering though, if this was terribly necessary to fix, or if it will cause more problems in the future if neglected. because if not, i will wait until i have time to do it. so far it hasnt affected anything really, so i may postpone repairs for now.

simplyxtrippin · 02-13-2007, 08:47 PM

ryuji, where in Baldwin Park are you from? I'm from BP too. I have the same year and engine too.

ryuji16 · 02-13-2007, 09:11 PM

i live a few blocks from home depot and walmart.

you got the same problem? i really have to fix this VERY soon, i have a smog check due before 2/22. im getting quotes everywhere for the knock sensors for 150-300 a piece. there are 2 freaking sensors, so i might need 2, but theres no way to be sure how many i actually need. fubar if you ask me.

***Eye8Pussies*** · 02-13-2007, 09:19 PM

Quote:

Originally Posted by toyomoho

The knock sensor can be tested with an ohmmeter. It should not have electrical continuity.

what he said...

but to get them out, unfortunately, you have to go further than removing the intake plenum. you in fact have to remove the intake manifold and then you'll see one sensor on the rear of each bank of the engine

first check the wiring to see if there are any frays, cuts, etc. and also check the knock sensor continuity.

if one of them is in fact blown, then you can always splice and rewire both signal wires to one sensor on one bank to keep the ecu happy

and this is something that you will most likely want to have fixed before going for emissions testing because it DOES effect the way your car drives. when the knock sensors are either sensing knock and retarding timing, or doing the same thing when the CEL is on, your car is running extremely rich and (from my own experience and dyno results) the car is in fact losing almost 20whp. the retard may not be as great with the 3vz's obdI computer, but there is no doubt that something is being done when the CEL is on due to knock sensors to prevent possible detonation.

Toysrme · 02-13-2007, 10:17 PM

When the knock sensor shorts out when it is effectively dead. All of the Toyota ECU's I know of return to an entirely different base timing of 5*btdc. (Stock abse timing for diagnostic mode is 10*btdc).

Check / replace the sensors & wiring.

ryuji16 · 02-14-2007, 01:13 PM

yea, i know what kind of trouble it is to get to them. but i cant do any of this myself.

this is really gonna hurt isnt it.

great.

***Eye8Pussies*** · 02-14-2007, 01:36 PM

if you pay somebody else to do it? then.....yes.

about 200CND per sensor, and then 200 for labor to get to them

as well, I don't know if a mechanic would be willing to wire up two into one and take responsiblity for that....

but if they are willing though, you could get lucky and get off with just the labor if only one sensor is blown

thaharlequin · 02-14-2007, 03:35 PM

If you reset the ECU, how long/many miles do you have before it comes on again? If it's long enough, you can reset it, drive around until idle gets back to normal, and have it smogged.

Toysrme · 02-14-2007, 04:27 PM

About 30-90 seconds...

***Eye8Pussies*** · 02-14-2007, 04:34 PM

^ lol...yup....

thaharlequin · 02-14-2007, 08:05 PM

f'n knock sensors. if you left the circuit open, would the ECU think everything was ok?

***Eye8Pussies*** · 02-14-2007, 08:20 PM

^ nope...it needs a constant variable reading from the knock sensors...

what can be tried though is a cheap way of bypassing a knock sensor (presuming you know which one it is that's blown- if not both).

you can tap/rewire the knock sensor signals at the ecu to read off of one sensor. this will save the trouble of taking off the intake plenum and manifold to get to the sensors on the block