Honda Civic Service Manual page 287

PGM-Fl System
6 .
1 .
DTC Troubleshooting (cont'dl
DTC P0500: VSS Circuit Malfunction
1. Test-drive the vehicle.
2. Check the vehicle speed with the scan tool.
ls the correct speed indicated?
YES-lntermiftent failure, system is OK at this time.
Check for poor connections or loose terminals at
t h e V S S a n d a t t h e E C M . I
NO Go to step 3.
3. Turn the ignition switch OFF.
4. Block the rear wheels, and set the parking brake.
5. Raise the front ofthe vehicle, and make sure it is
securely supported,
Turn the ignition switch ON (ll).
Block the right front wheel, and slowly rotate the
left front wheel.
8. Measure voltage between ECM connector
t e r m i n a l s A 1 8 a n d A 2 4 .
ECM CONNECTOR A {31P)
Wire side of female terminals
Does the voltage pulse between 0 V and 5 V or
between 0V and battery voltage?
YES-Update the ECM if it does not have the latest
software, or substitute a known-good ECM. then
recheck (see page 1 1-6). lf the symptom/indication
goes away with a known-good ECM, replace the
o r i g i n a l E C N 4 . l
NO Go to step 9.
1 1 - 8 0
9. Turn the ignition switch OFF.
10. Disconnect ECM connector A (3'1P).
1 1 . T u r n t h e i g n i t i o n s w i t c h O N { l l } .
12. Blockthe right front wheel. and slowly rotate the
left front wheel.
'!3.
lMeasure voltage between ECM connector
t e r m i n a l s A 1 8 a n d A 2 4 .
ECM CONNECTOR A I31PI
Wire side of female terminals
Does the voltage pulse between 0 V and 5 V ol
between 0V and battety voltage?
YES Update the ECM if it does not have the latest
software, or substitute a known-good ECM, then
recheck (see page 1 1-6). lf the symptom/indication
goes away with a known-good ECM, replace the
o r i g l n a l E C M . I
NO Check these items:
. A short or an open in the wire between the ECM
( A 1 8 ) a n d t h e V S S . I
. l f t h e w i r e i s O K , t e s t t h e V S S ( s e e p a g e 2 2 7 1 ) . 1