My main question is:

What can cause a code 21?

-wiring (shorts, bad wiring to ecu, bad grounds)
-bad solenoid
-bad ecu
-low oil pressure

anything else?

Just finished my GSR swap into my 92 Civic VX hatch, obd1 P72 ECU, obd2 GSR harness, obd2 GSR distributor, obd2 injectors, obd2 alternator. Secondaries work, everything else works, but just throwing a code 21.
I'm out of ideas.
Checked all the VTEC wires with a multiscanner and they are all running to the correct places from the solenoid and pressure switch to the ecu. solenoid to a4, pressure switch to d6.
Checked the solenoid, it clicks, even swapped out for a working one, and it still throws the code.
Next step switched ECU's and still get the same CODE 21.
Checked the continuity of all wires and they all are good.
Changed the oil after the swap was in.

The weird thing is that the engine light comes on less then a second after I start the car. I reset the ECU and it still comes on in less then a second after starting the car.

I unplugged the VTEC pressure switch and turned the car on and it throws the same code 21, i thought it would throw 22 for VTEC pressure switch?
If I unplug the VTEC solenoid it throws the same code 21, if I unplug them both it still throws the same code.

what else can cause the ECU to automatically throw code 21? any other sensors have input to this code?

is there any parts under the valve cover or inside the head/under the cams I should check to see if they are there? would missing those cause the code 21 to pop up within a second after turning the car on after resetting the ecu?

Any ideas or suggestions?



Modified by inline4 at 8:59 AM 7/26/2006


Modified by inline4 at 11:25 PM 7/26/2006

 

did u wire up ur knock sensor ?

 

yeah, i'll double check if it's going to the right location with the multimeter.

could that be a cause of the code 21?

i'm going back and forth from the garage to honda-tech.. lol. reading, replenishing my thirst, trying all sorts of things.

 

i was a having same problem... yet, i got my car jacked while i was trying to find out what the problem was... ... good luck

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by inline4 &raquo;</TD></TR><TR><TD CLASS="quote">yeah, i'll double check if it's going to the right location with the multimeter.

could that be a cause of the code 21?

i'm going back and forth from the garage to honda-tech.. lol. reading, replenishing my thirst, trying all sorts of things.</TD></TR></TABLE>

TAKE UR PC TO UR GARAGE that what I did when i was putting my motor together , i had the manual on my pc

 

up

 

hhaha,, stupid me. turns out that pin A4 at the ECU wasn't making contact with the ECU. lol.. all this time, troubleshooting and tracing wires, and trying everything turns out to be the stupidest thing ever. all I had to do was take pin A4 out and push in a little metal tab on top of the pin so that the ECU pin would make contact.