Honda Civic Service Manual page 404

PGM-FI System
Throttle Position (TPl Sensor ('99 - 00 Models except D16Y5 engine with M/T)
lTO12Z _TI
scan tool indicates Diaqnosttc Trouble Code (DTC) P0122: A low voltage problem in the Throttle position
-
{ | r, sensoa crrcurl.
The TP Sensor is a potantiometer. lt is connected to the throttle valve shaft. As the throttle position changes, the throttle
position sensor varies the voltage signal to the ECM/PCM.
ERUSH
HOI.DEN
OUTPUT VOLTAGE (VI
BRUSH
BESIS?OF
TERi'I AL
5
4
3
2
1
o
INNER
BUS}IING
THROTTLE
OPE II{G
FULL
THROTTLE
TP SENSOR 3P CONNECTOR {Cl1OI
sG2
IGRN/8LKI
vcc2
(YEUBLUI
Wire side of temale terminals
ECM/PCM OONNECTOR C 131P)
Ch.Gk for rn opan or 3hort in TP
36nlot:
1. Turn the ignition switch OFF.
2, At the sensor side, moasure
r e s i s t a n c e b e t w e e n t h e T P
sensor 3P connector terminals
No. 1 and No. 2 with th€ throt,
tle fully closed.
(To page 11-135)
-
Th. MIL har boon.6portcd on.
-
DTC P0122 b siored.
Problem verification:
1 . S t a r t t h e e n g i n e , H o l d t h e
engine at 3,000 rpm with no
load (in Park or neutral) until
t h e r a d i a t o r f a n c o m e s o n .
then turn the ignition switch
OFF,
2. Turn the ignition switch ON (ll).
3 . C h e c k t h e t h r o t t l e p o s i t i o n
with the scan tool.
ls there approx. .49 V when
the throttle is fully clos€d and
approx, 4.5 V when the throttle
is fully opened?
l||t rmittont failura, lyrtom b OK
at thi! tima. Chock tor poor con-
nactionr o. looao wires rt C110
{TP 3.n!or} rnd ECM/PCM.
Check for an opan or 3hort in tho
wi.c (VCC2 linc):
1. Turn the ignition switch OFF.
2. Disconnect the TP sensor 3P
connector,
3. Turn the ignition switch ON (ll).
4. Measure voltago between
the TP sensor 3P connector ter
minals No. 1 and No.3.
ls thero approx. 5 V?
Chccl tor .n opln in wiro IVCC2
lin€l:
Mgasure voltago between ECM/
PCM connector terminals C18 and
R.prir opcn in the wiro bctw.en
ECM/PCM (C281 and TP 3€nror.
ls there approx. 5 V?
Subrtituto r known-good ECM/
PCM .nd rochcck. lf pro.c.ibed
voltaga i! now available, roplaco
tho origin.l ECM/PCM.
Wire side ol female terminrls
T e r m i n a l s i d e o f m a l e t e r m i n a l s
1 1 - 1 3 4
L