Rep Power: 0

2001 Honda Civic LX.
201,000 miles.
Error codes are: P0501, P1298, and P0720.
Now what?

It's been acting weird... one morning drive light flashing and speedometer going all over the board. Next day, fine, nothing. Now occasionally while driving the speedometer revs and falls away not reading correctly.

Where do I go from here? How do I find out if its transmission trouble, alternator, or what? (this is a not-mechanically- inclined person and really tired of paying mechanics and ending up with more problems)
Thanks

 
Rep Power: 156

first you search the forum for the error code. This would lead you to this thread:
https://www.civicforums.com/forums/3...i-codes-2.html

then you would find:
P0501 Vehicle Speed Sensor (VSS) Range/Peformance Problem
P1298 Electric Load Detector (ELD) Circuit High Voltage
P0720 Countershaft Speed Sensor Circuit Malfunction

now research this stuff and see if it's something mechanical or just a sensor.

 
Rep Power: 518

P0501/P0720......assuming both are circuit problems......did they occur at the same time? Rodents chewed wires?
EDIT: Apparently a fault in one sensor might cause a code for the other....I might whip out my scanner, set up live data list, and see if one of those sensors is not alive and reporting a speed signal.


ELD code is common to be found in memory (common problem), but that alone should not turn on the CEL. You can get a brand new ELD for like 40 bucks from Honda.

 
Rep Power: 0

So I did search the forums first for the error code.
I actually got more cryptic answers than what drhawkinz got.
(speed sensor circuit, electrical load, and auto transmission).

I also "searched this stuff" to see if its something mechanical or just a sensor. Hence posting my question here. Maybe google would be better to try to figure it out? Maybe I do need to pay the mechanic for the diagnostic? Or just sell it? i dont work on cars, dont know much mechanically about them. But I did check wires and do what I can to inspect... no rodents chewed wires. fixed the loose wire to the battery. Beyond that I'm stumped. I dont have a scanner... so....

 
Rep Power: 222

So you had a loose battery cable?
That may have caused weird electrical problems.
Double check that the bolts and connections are tight for the alternator.
If you leave the battery disconnected for 20 mins that should wipe the computers memory and the codes.
Then reconnect, do an idle relearn (search the forum) and then go for a drive see if anything comes back

 
Rep Power: 518

Welllll, if you can obtain a scanner that will display live operating data for the engine and the transmission, that would go a long way toward removing some arbitrary guessing. If you don't have access to some of (what I consider to be) pretty basic equipment for working on a car made during the last 23 years, you're kinda stabbing blindly in the dark.

I'd GUESS that since your speedometer obviously acts wrong, replace the VSS first...then erase fault codes, then drive it and see if the P0501 and/or the P0720 code comes back and/or the speedometer acts right.



The P1298 code will keep coming back sooner or later until it is replaced, but that's not causing the other two codes and it is not causing a driveability problem.

 
Rep Power: 156

Google will search this forum and various other places on the web.

Take a look at this: https://www.autocodes.com/p1298_honda.html

And also maybe this: https://www.autocodes.com/p0501_honda.html


If you feel confident enough to diagnose and replace the sensor then go for it.