ce1 boy

ok so i have a 96 accord wagon lx non vtec auto trans about 152k on shell! so ill try to go bak and bring you guys up to date so about a year ago my cel came on and my d4 started blinking at the same time but car drove fine i went home and scanned check engine code it came out p0720 output shaft speed sensor circuit so i changed the designated sensor but light camew back on so i checked harness and plugs,harness was good and plugs were good as well so i tried another speed sensor,same problem cel code p0720 so i changed all speed sensors all 3! still the same code so then i decided it was tcu well since my car is 96 the put the tcu in with ecu so i replaced the computer from a 97 special edition non vtec auto trans,drove about 3 miles boom cel same code! so i got fed up and changed the tranny with all 3 speed sensors that were in trans wen i took it out of a (crashed) accord in junkyard,drove car about 3 miles low and behold same freakin code p0720 so i got fed up created a post here( didnt get much feedback) and just started going over everything again! well i was in the car doing some thinking and messing with obd scanner! well i remembered when i bought the car 3 years ago the shift lock never worked properly i could always pull the car from nuetral to park without pressing brake but not out of park,also i could take key out ignition while in neutral as well but never paid much mind to it actually kinda liked it!but here comes the weird part! i havent moved the car for a couple days and last time i was in the car i KNEW i cleared check engine light but apparently (prob cause i was smokin lol) i left car in neutral with e brake on! well today i started the car and immediately the check engine came on and d4 started blinking funny part is it only ever came on when i drove for alittle so i was confused and pulled out the scanner checked it no more p0720 (prob cause i didnt move car yet) but i had p0753 shift solenoid a malfunction so i cleared the code and started car (in nuetral) and same code p0753? so i cleared it again and put car in park and started it,left idle for about 10mins no code? so i looked more into p0753 says replacre solenoid so i was gona grab one off a friends car and see if it shut that code off and if i drive it if it will pop p0720 again or not but when i started car to go cel light and d4 pop on and d4 blinking so i went to reset it to see wat happens when i drove and immediately after i reset it they both pop RITE bak on and i mean immediately like rite after they fully clear bam scanners piks up code rite away and lights go on ima look more into it tom in daylight but jus wondering if a anybody can help at this point any help would be great this obd 2 **** is getting nuts especially since i have to turn off cel to pass emmisions smh...

ce1 boy

ok just a quik update i jus went to take the car to the store to drive it and see wat codes i get cause this is gona drive me crazy like possibly lose sleep crazy lol! anyway i took car to store cel was on and d4 blinking car pulled off fine and drove thru first fine but wen it switched it felt like car went rite to od or 4th gear so ima change out solenoid tomorrow as i think it did go bad bud i onlt took car couple blocks cause i didnt wana drive it like that far but wen i rescanned it no p0720 so maybe it wasnt far enuff or maybe this solenoid been causing all these troubles but i will update tomorrow after i change it if that dont work gona change shifter assembely maybe shift lock or nuetral safety switch ****** wit it??? fingers crossed if none of this works bak to square one again?? start over i guess lol

brigman262

did you ever figure out a solution to the 720 code problem?

MAD_MIKE

FWIW, P0720 is for the NC shaft sensor on the trans.


Check for resistance at the sensor connector, check it at the PCM connector.
However, albeit, if the transmission has high mileage and the fluid has not been frequently changed, the sensor may simply be slurry fouled.
Remove it and verify the end is clean of debris. If the NC sensor is filthy the NM sensor is most likely in the same condition. Clean both, as they affect shift quality.