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View Full Version : CEL on from sensor/ heater malfunction, bank 1

devonkyle77
08-09-2006, 07:43 PM
sensor/ heater malfunction, bank 1

thats what the code was that threw a CEL on my 97 240sx

how do i diagnose this?
i changed the 02 sensor a few months ago.
g6civcx
08-09-2006, 11:01 PM
#1 in my sig. EC section. Page 132.
bongnak
08-10-2006, 01:16 AM
heater bank 1 means o2 before the cat. so the o2's heating functions no worky. also look under the hood if its still stock, theres an emissions tag and should tell u if you need a o2 sensor or an air fuel meter sensor, IT does matter!. trust me. take a pic of the tag and i can show you. try not to use autozone universal sensors too...
devonkyle77
08-10-2006, 06:43 AM
the only 02 sensor i can find is the one that goes into the exhaust manifold. where is the other one?
devonkyle77
08-10-2006, 06:44 AM
and where is the emissions tag and air fuel meter sensor?
g6civcx
08-10-2006, 07:00 AM
The OBDII S14s have 2 O2 sensor. The secondary is further downstream.

Did you do #1 in my sig? Nobody will spoonfeed you.

Well, I'll spoonfeed you if you show effort, and Russ will spoonfeed you but he'll call you all kinds of names. Half of the rest of the people don't know what's going on, and the other half will flame you for not trying.
devonkyle77
08-10-2006, 07:12 AM
i have a full aftermarket exhaust, starting with a downpipe. no bungs for 02 sensor. i dont see an 02 sensor further down at all.
yes i did number 1.
projectRDM
08-10-2006, 07:15 AM
Bingo. Secondary O2 sensor is used for OBD purposes only but is required or it will throw a code. Primary is for air/fuel mixture, car runs open loop without it.

The secondary is supposed to be mounted in the downpipe, downstream from the catalytic converter. The plug comes off the lower harness, should be just hanging by the tail end of the transmission.
g6civcx
08-10-2006, 07:47 AM
Weld on a secondary O2 sensor bung, or get an OEM-replacement unit.

As for non-street legal options, you can get an O2 simulator, bypass the CEL, or run a piggyback/standalone ECU.

i have a full aftermarket exhaust, starting with a downpipe. no bungs for 02 sensor. i dont see an 02 sensor further down at all.
yes i did number 1.

Page 7 of the FE section.

http://g6civcx.angryhosting.com/S13/Tech/S14Exhaust.jpg