Hi guys, random guy with a 2002 Accord Sedan EX 2.3. Been on the forums for a few years now and I've searched low and high but I cannot for the life of me figure this out. Heres the situation, my car has 225k with good service intervals 2 owners the lot. I CANNOT use vtec (past about 4200 rmp) outside of first gear, and I do not understand why. The car has no oil leaks, has brand new ignition, good compression, solid electronics, and little to no apparent deterioration of anything that important. I've pulled the vtec solenoid and checked the screen and it's clean. Here's what codes the car has, downstream o2 sensor ( dont have one and vtec didn't work before I didn't have one) a code for the knock sensor (I again I am pretty sure the car doesn't have one and never has but at one point in time years ago vtec DID WORK mind you reader) a code for the vtec system failure itself, and a code for the the evap system. The car runs good and has good power with good shifts up to 4200 rpm, then limits itself as if something is wrong. I have checked and checked again but please someone give me something to go off of here. I want to keep the stock engine, but not being able to floor an already slow car is painfully slow so I've been toying with the idea of just buying a low mile jdm motor and swapping it. Anything at all or any theory's are welcome, a true mystery for me for multiple years has finally made me come and ask for help. I'm almost ashamed to ask but holy **** is it annoying chasing a problem like that.
much love - pez

 

share the code numbers please.

there is a knock sensor on the block near the oil filter.

VTEC for the F23A1 increases lift but also "activates" the secondary intake valve on each cylinder (swirl port at low rpm, tumble at high- VTEC on) so it is available from something like 2700-4000 rpm then solid on up to redline. What you describe sounds more like limp mode but could still just be VTEC... need those specific codes to make more sense of it.

 

hi Mark good morning and good seeing you. Been a few good rainy days so i havent had the opportunity to go write them down. But here we go. Codes P1259 P1279 [vtec system failure] P0330 P0327 [knock sensor failure] P0141 P0161 [heater circuit codes???] The other day I had a code for evap and now that's gone and been replaced with heater circuit codes I guess. This isn't a major code red situation for me, been driving it granny mode for a year or more now just finally am getting annoyed by it. I did clear all my codes and unplug my battery for 30 minutes or so the other day and then drove it with no change just to see if it was something the ecu had stored. Interesting interesting. Would love any input, either way hope you're doing okay - pez

 

P0325 for the knock sensor, P0141 for the O2 Heater, P1259 for VTEC all share ECM connector C (31 pin) and all have short or open wire as possible causes. I would start there.