Surges While Cruising - Mazda 121 Workshop Manual

TROUBLESHOOTING GUIDE
F
t a
SUFGES WHILE CRUISING
DESCRIP.
TION
. Unexpecled chanSe in engine speed wnich is usually repetitive
TIROUaLESHOOTTNG HTNTSI
O Air/Fuel mixture loo ean
@ Misfirc
@ Poor connection in wiring harness
STEP tNSPECT|Ot{ ACTION
ls '0O displayed on SellDiagnos s Checker
wth ignition swltch ON?
c? page F-€?
Go 10 next slep
No
Malluncllon Code No. displ.yed
Check for cause {Beler lo soecilied
ch€ck s€quenc€)
!? page F-70
"88" llashes
Check ECU ielminal 1F voltage
e p.ge F-114
Vo[age: Approx. l2V
(lgnilion sMtch ON)
+
lf OK, replace ECU
r? page F-112
+
lf not OK, check wirins benxeen
ECU and Self-Diagnosis Checker
2 ls throttle seosor OK?
s D 4 g e F - 1 2 2
Go ro ne( step
N O
3 Disconnect oxyg€n sensor connector; does con'
OXYGEN SENSOR CONNEC] OFt
Check oxygen sensor
(? eage F-123
Are ECU terminal voltages OK?
t- page F-112
Check tor cause
.7 pege F-115
F-117
F-It9
5 ls lh.ottle linkage cofrecly installed and does
thronde valve open op€raies lrcely?
Corfecl, clean, or replace as requircd
any binding or damaged linkage, and
adiusl calte dellection at injeclion
body
F page F-{6
6
ls there air leakage oi inlak€ arr system com-
7
ls arr cleaner element clean?
o
page F-62
Beplace air cl€aner elemenl
F-45