Help! P0720 Code 2003 Honda Odyssey

[DaddyBlogger]

I would appreciate any thoughts on this. I pray this isn't my 2003 Honda Odyssey's AT going out...they are not reliable.

Have diagnostic code of P0720 which is the Countershaft Speed Sensor Circuit. Is this the start of the dreaded "your tranny is dead" code?

This occurred just after I exited a car wash which could be just be a freak thing or perhaps something got wet? After pulling out of the car wash my van shifted really strange the TCS and check engine light both came on and the "D" gear slector display started blinking green instead of a solid green. I stopped driving the van for awhile and now the only thing lit is the check engine light. The van now shifts like nothing ever happened but still gives me a code of P0720. Any thoughts?

 

[Gary Allan]

Quote:
Is this the start of the dreaded "your tranny is dead" code?


No, it sounds like your speed sensor has issues and that's causing (or did cause) the trans to shift funny.

Replace the sensor. First attempt to clear the code by disconnecting the battery. If it comes back on ..or you experience the same anomaly with the same ultimate result, change the sensor.

It should be a relatively easy task.

 

[mopar_monkey]

well i've been a honda tech for many years and typically if we see this code it needs a tranny, but since you had gotten it washed and the tcs light flashed and the "d" blinked i'd say your tires were wet and you had some tire spin,since it was seeing diffrent wheel speed then it should have it set the code thinking something was a miss. clear it and see if it comes back, keep that tranny serviced every 30k at the MOST!

 

[Gary Allan]

Can you explain the back reasoning on the trans failure due to this code being present? This is a sensor code not a "mismatch on engine/vss" code. That is, where the given conditions mean that there's some disconnect between engine input and road speed indication. Something like you would see if the trans slipped or the lock up tc didn't engage in spite of getting ground to engage. The TCM or PCM would see input speed not matching some projected output speed ...but the sensor(s) itself/themselves would show no problems.


..but I guess one would tend to associate the code with the failure if the failures always had the code present whether or not the reasoning was apparent. That's a hard one to ignore.

 

[Mokanic]

Originally Posted By: DaddyBlogger
I would appreciate any thoughts on this. I pray this isn't my 2003 Honda Odyssey's AT going out...they are not reliable.

Have diagnostic code of P0720 which is the Countershaft Speed Sensor Circuit. Is this the start of the dreaded "your tranny is dead" code?

This occurred just after I exited a car wash which could be just be a freak thing or perhaps something got wet? After pulling out of the car wash my van shifted really strange the TCS and check engine light both came on and the "D" gear slector display started blinking green instead of a solid green. I stopped driving the van for awhile and now the only thing lit is the check engine light. The van now shifts like nothing ever happened but still gives me a code of P0720. Any thoughts?

Get ready,a trannie is in your future.

 

[mopar_monkey]

with hondas scan tool this code is described as wrong ring gear ratio, what is happening is the trans is starting to slip and the speeds don't match up,it's not an issue with no connection to the sensor it's that the computer thinks the sensor is giving false readings,this is the code that sets as one of these trannys is starting to go, the code for trans slip comes on when you are having obvious slippage and would probably be taking to shop regardless of having a check engine light. but the generic obd code is for a speed sensor since it is part of the same system. now if he had the tire spin that would explain the tcs light, as the trans tried to sort out what was happening the "d" would flash and the computer could see this as a speed sensor problem

 

[DaddyBlogger]

I was going to say that Gary Allan was correct but later responses have made me concerned.

The comments I received on the OdyClub forum and through PM have leaned more towards Gary Allan's opinion. I pray that everyone else is wrong

As a note I have noticed ZERO odd shifting issues, no clunks when putting it in reverse, no slipping or delayed up shifts/ down shifts. It only acted bizarre during the first minute or so after coming out of the car wash.

I took it to the dealer and either they were honest or they are taking more of my money before the tranny fails. After looking things over they told me that my Countershaft Speed Sensor was cracked/falling apart. I looked and it seemed like what I saw confirmed their opinion. However, I do dread that after getting this repair that it will throw the main tranny failure code.

It may be the end of this Honda because I have heard horror stories even from people getting Honda's remanufactured AT and having it fail JUST after the 36K warranty is over.

 

[mopar_monkey]

i really hope it is just the sensor, i was'nt trying to scare you but i've seen and replaced 3 or 4 dozen of these trannys and i'd say 8 times out of 10 when you have that (and or a couple other) codes it's usually going, to keep these things alive you need to keep fresh fluid in the, i had one that in 45k i was putting the second tranny in it, so the owner started having us do a drain and fill on it every 6k or every other oil change, this seemed to really work well for him,last i saw of him he was at 130k and everything was good.the issue with these trannys is for one they only hold 6 qrts (that's total with torque converter) which is'nt much considering how big the van is and how much output the engine has, and for two there is NO filter in them.

 

[refaller]

Had a similar situation with my 2000 Honda CRV. The panic crowd said you need a new transmission. Research and a new shift solenoid later the car has been fine for 30,000 miles. In my situation, the car was not shifting right at the time either. I think your case is less sinister.

ref

 

[mopar_monkey]

Originally Posted By: refaller
Had a similar situation with my 2000 Honda CRV. The panic crowd said you need a new transmission. Research and a new shift solenoid later the car has been fine for 30,000 miles. In my situation, the car was not shifting right at the time either. I think your case is less sinister.

ref

that is also pretty common, well on the crv, but it has a diffrent code and the hondas hds scan tool can pick up the solenoid pretty easily,i don't think it's really a panic issue it's just that these years of odyssey have so many wide spread trans problems that this is a very good indicator that it's on it's way down hill, crv's have very few trans issues so it is really comparing apples to oranges.