1.0 INTRODUCTION
Th e pr ocedu res con t ain ed in t h is m a nu a l in clu de
all of t h e specifica tion s, in st r uct ion s, an d gr a ph ics
needed t o dia gn ose NAG1 Elect ron ic Au t oma t ic
Tra n sm ission a n d Sh ift Lever Assem bly pr oblem s.
Th e dia gn ost ics in th is m a nu a l ar e ba sed on th e
failu r e con dit ion or sym pt om bein g pr esen t at th e
tim e of dia gn osis.
Wh en r epa ir s a re requ ired, r efer t o th e appropr i-
at e volu m e of th e ser vice in forma t ion for t he pr oper
rem ova l a nd r epa ir pr ocedu re.
READ TH IS MAN U AL BEF ORE TRYIN G TO
DIAGNOSE A VEHICLE TROUBLE CODE.
Dia gn ost ic pr ocedu r es ch a nge ever y yea r. N ew
dia gn ost ic syst em s m ay be a dded a n d/or ca rr yover
syst em s may be enh a nced. It is r ecom men ded t ha t
you r eview t he en tir e m a nu a l t o becom e fa milia r
wit h a ll new an d ch a nged dia gn ost ic pr ocedu res.
1.1 S Y S T EM COV ER AGE
Th is dia gn ost ic pr ocedu res m an u al cover s all
Spr in t er (VA) equ ipped wit h a NAG1 Aut om a tic
Tra n sm ission .
1.2 SIX -STEP TROUBLESHOOTING
PROCEDURE
Dia gn osis of t h e NAG1 elect r onic t r a nsm ission is
don e in six basic st eps:
Ver ifica tion of com pla in t
Ver ifica tion of a ny r ela t ed sym pt om s
Sym pt om an a lysis
Pr oblem isola t ion
Repa ir of isola t ed pr oblem
Ver ifica tion of pr oper oper a t ion
2.0 IDENTIFICATION OF
SY ST EM
Th e NAG1 Tra n sm ission fa m ily ca n be ident ified
by th e pr esen ce of a 13 pin elect r ica l conn ect or, wit h
a ba yon et lock on t he righ t h a nd side of t he tr an s-
mission . Th e con nect or is or ien t ed hor izon t ally.
3.0 SYSTEM DESCRIPTION AND
FU N CT I ON AL OPERAT I ON
3.1 GENERAL DESCRIPTION
Th e NAG1 elect ron ic tr a n sm ission is a n elect r on -
ica lly con t rolled five speed t ra n sm ission wit h a
cont r olled slip t orqu e con ver t er. Th e NAG1 elec-
tr on ic tr an sm ission is a con ven t ion a l tr a nsm ission
in t ha t it u ses h ydr a u lica lly applied clut ch es t o shift
a pla n eta r y gea r tr a in . H owever, t h e elect ron ic
cont r ol syst em repla ces m an y of t he mech a n ica l an d
hydr a u lic com pon ent s u sed in conven tion a l t r an s-
mission va lve bodies.
Th e r a t ios for t h e gea r st a ges a r e obt a in ed by 3
pla n et ar y gea r set s. F ift h Gea r is design ed a s an
Over dr ive wit h a h igh speed r at io. Th e gear s ar e
act u at ed elect r onica lly/h ydr au lica lly. Th e elect r on ic
cont r ol syst em ena bles pr ecise a da pt at ion of pr es-
su res t o t h e r espect ive oper at ing con dit ions a n d t o
th e en gin e ou tpu t du r in g a sh ift ph ase, wh ich
resu lt s in a significa n t im pr ovem en t in sh ift qu a l-
ity.
3.2 FUNCTIONAL OPERATION
Th e N AG1 elect ron ic t ra n sm ission h a s a fu lly
ada pt ive con tr ol syst em . Th e system per for m s it s
fun ct ion s based on con t in u ous real-t im e sen sor an d
swit ch feedba ck in for m at ion . In a ddition t h e TCM
receives in for m a t ion fr om t h e Sh ift Lever Assem bly,
ECM (en gin e ma n agem ent ) an d ABS (ch a ssis sys-
tem s) con t r oller s over t he CAN bu s. Th e CAN bu s is
a h igh speed comm u n ica t ion bus tha t a llows r ea l
tim e con t r ol ca pa bilit y bet ween va riou s con tr oller s.
Most m essa ges ar e sen t ever y 20 m illisecon ds, th is
mea n s crit ica l in for ma t ion ca n be sh ar ed between
th e Tra n sm ission , Shift er, E ngin e a nd ABS cont r ol-
ler s. Th e CAN bus is a t wo wir e bu s wit h a CAN C
Bus (+) circuit and a CAN C B u s (-) c irc u it.The
CAN bus u ses a t wist ed pa ir of wir es in t h e h a rn ess
to r edu ce th e pot ent ia l of ra dio a nd noise in t er fer-
en ce. The CAN bus a lso u ses a 120 oh m ter m in a t in g
resist or in bot h t h e E CM an d Sen tr y Key Rem ot e
En t ry Module (SKRE E M) m odu les. Th e m odu le
ter m in a tin g resist a nce is m ea su red a cross bot h
CAN bu s cir cuit s at th e E CM or SKRE EM module.
Th e con tr ol syst em au t om at ically ada pt s t o
cha n ges in en gin e per for ma n ce, veh icle speed, a n d
tr a nsmission t em pera t ur e va r ia t ion s t o pr ovide
consist ent sh ift qua lit y. Th e con t rol system en su res
th a t clu t ch oper a t ion du r in g u psh ift in g an d down-
sh ift in g is m or e r espon sive wit h out in cr ea sed
ha r sh ness. Th e TCM con t rols t he act u at ion of sole-
noid valves for m odu la t in g sh ift pr essu r e a nd gea r
cha n ge. Th e r equ ir ed pr essu re level is ca lcu la t ed
from th e loa d con dit ion, en gin e speed. Power for t he
tr a nsmission syst em is su pplied t h rou gh th e Tra n s-
mission Rela y. Th e TCM is loca ted in the u nder th e
dr iver s sea t of t h e veh icle.
Th e Tr a nsmission Con t rol Modu le (TCM) con t in -
uou sly ch ecks for elect r ica l pr oblem s, mech a n ica l
pr oblem s, an d som e h ydr au lic pr oblem s. Wh en a
pr oblem is sen sed, t he TCM stor es a dia gn ost ic
tr ou ble code (DTC). Som e of t hese codes ca u se t he
tr a nsmission t o go in to "lim p-in " or "defa u lt " m ode.
1
GEN ERAL I N FORM AT I ON
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