Manager Forum

Have '98 Honda Civic DX 4dr Auto/AC

Speedometer jumping when sitting still ....VSpeed Sensor reading mph when sitting still car will not go thru gears seems in 4th and will not back up in rev. Intemittent problem just started today........Trans code po720 po700 and p1298 ....understand what they are but having difficult time in diagnosing correct repair ....I checked Alternator reading 12v at idle....when car is acting up car will not back up....but when not actiong up backs up and shifts fine...Has anyone seen this before and what corrected issues?

Thanks Stan

Scope out your VSS make sure it's working properly. Incorrect VSS input can cause shifting problems (kind of weird about reverse though). Ran across the P1298 code before:

SYMPTOM
DTC P1298 (electrical load detector (ELD) circuit high
voltage) is stored in the ECM/PCM.

PROBABLE CAUSE
The electronic load detector (ELD) has a faulty solder
joint.

CORRECTIVE ACTION
Replace the ELD.
NOTE: Previously, if an ELD required replacement, you
had to replace the under-hood fuse/relay box. To
reduce repair costs, replacement ELDs are now
available.

PARTS INFORMATION
Electronic Load Detector:
P/N 38255-S5A-003, H/C 7987571

I suspect that the Alternator is not putting out voltage correctly only 12v this can cause eratic trans signals ....as far as p1298 ELD possible ....I can clear code and just switch car to run and it will reset code p1298 ....Is this what is common with the ELD going bad...as far as other codes I believe them to be caused by Alternator or Spike from ELD.....

In testing this afternoon I found #15 underdash fuse blown ALT/SV checked TSB found a listing saying code p1298 ELD po135 o2 an po141 o2....with po501 svs....check for blown fuse #15 ....also said check main engine wiring harness brakcet for rubing into wiring...repair and cover and resecure.....have not checked harness but did replace fuse ....now Alt is 13.5 to 14 v and charging car shifts and runs fine...only code that comes back is o2 po135....will post any additional findings....

If all you were getting was 12 volts then that was probably your problem.

check harness where it runs through support bracket. dimes to doughnuts it's chafed. repair harness don't just tape it. pain in the butt, but if the alternator feed wire is chafed and the amp load is compromised it will roast under a heavy load and won't blow a fuse. oh ya, i think you'll find the 02 issue there as well.