frostdragon1

just bought a 98 civic ex a/t only has 89k but there are three codes that are on the cel. all of which are circuit malfunctions. car runs fine in park/ neutral and while moving. but at a light the car idles at 300/400 rpm and vibrates badly. codes where cleared at autozone and i sat in the parking lot of like 30 min on the phone with no codes but as soon as i drove the codes came back on. already replaced the mounts and speed sensor (p0720). thinking its a open wire somewhere but have not found anything.just yesterday i started the car and it wouldn't shift out of park had to start the car 3 times to get it to shift

94EG8

Check out this TSB first --> http://www.tegger.com/hondafaq/tsb/civic/x99-029e.pdf I'd also check the VSS plug as they often corrode. If you don't have a wiring issue the knock sensor is probably bad.

frostdragon1

thanks for that TSB it will help me find the issue quicker. i hope thats all it is cause replacing all these sensors is becoming costly.

Former User

None of your codes (p0325/knock sensor, p0700/P0720/transmission countershaft speed sensor) fits with the fuse 15 TSB.

Start by checking whether those sensors are plugged in.

frostdragon1

i checked the sensors and there is no corrosion on the leads and all are tight and in properly.... this is becoming very frustrating. still having problems getting out of park every now and then.

Former User

Check the wires for a short or open using a multimeter. If the wires are fine, then the sensors or ECU may be bad.

frostdragon1

well i already replaced the countershaft vss so the only one to replace is the knock sensor. im going to look at all the wires tomorrow and ill let you know what i find. thanks for all your help.

frostdragon1

Well I lifted the car in the air to really get a good look at the main wiring harness behind the engine with out taking the intake manifold off and to my lovely suprise plugged in the knock sensor harness was 1/2 of the sensor... Sigh another sensor broken. This one is 137.99 I really hope that fixing this will put an and to my troubles. Although I must say I'm lucky that there dose not seem to be any engine damage I'll knock on wood and keep my fingers crossed in high hopes. Buying sensor today as soon as autozone opens then sleep as I work howl o scream tonight. Will post if problems are fixed or not with trany and the three codes thanks all.

Former User

Good luck. You really only have two codes. P0700 and P0720 are redundant in that P0700 only tells you that there is a general transmission sensor circuit problem.

frostdragon1

well i pulled the tcu out from under the passenger kickplate and there are 2 wires that have been tapped into and ghetto grounded (like three peices of wire tied toghter with tape) but i cant find a wiring dighram for the tcu anywhere to see what they tried to accomplish so i can fix it the CORRECT way. anyway i took all thoise wires off and codes still show and trany is still acting up. got everything else fixed but that.

Former User

http://www.phearable.net/tech/wiring...schematics.gif

frostdragon1

k i checked the wires for an open circuit (remover the engine wiring harness and tcm) found no broke wires or shorts.... tested with meter for oms and the white/ blue wire off the counter shaft speed sensor is showing no reading (open/broken) but no visable break... should i wire in a new wire? and again thanks with all your help ron!!!

Former User

Good job. If you cannot locate the break, running a new wire is the next option to consider.

frostdragon1

ran new data wire to the tcu but codes still on. lets see.... should the ground ohm out? and the power wire to the sensor should be at about 12- 13 volts right?

frostdragon1

im going to try running a new ground to see if thats the issue.

frostdragon1

re wired the sensor with no luck im at a loss and think its time to suck up my defeat and take it to honda...

frostdragon1

new tranny and torque converter, seems to fied the issues with the codes and there are to wire connectors on that side of the engine that have the same connector. one gose to the vss the other to the charcoal canister i think. honda said they where mixed up by whomever sold it to us and was causing issues. car still idles poorly though thinking i have to dissasemble the throttle body and CLEAN everything. prob the cause. seems like whomever put this engine back in the car broke every sensor and miss mached every plug there was. pita to have to deal with all this just to get the car runnung right