Dodge Sprinter 2006 Manual page 421

3.2.6 SKREEM OPERA TION
Wh en ign it ion power is su pplied t o t h e SKRE E M,
t h e SKRE E M per for m s a n in t er n a l self-t est . Aft er
t h e self-t est is com plet e, t h e SKRE E M en er gizes
t h e a n t en n a (t h is a ct iva t es t h e t r a n spon der ch ip)
a n d sen ds a ch a llen ge t o t h e t r a n spon der ch ip. Th e
t r a n spon der ch ip r espon ds t o t h e ch a llen ge by gen -
er a t in g a n en cr ypt ed r espon se m essa ge.
Aft er r espon din g t o t h e coded m essa ge, t h e t r a n -
spon der sen ds a t r a n spon der ID m essa ge t o t h e
SKRE E M. Th e SKRE E M com pa r es t h e t r a n spon -
der ID m essa ge t o t h e a va ila ble va lid key codes in
SKRE E M m em or y (8 key m a xim u m a t a n y on e
t im e). Aft er va lida t in g t h e ign it ion
SKRE E M sen ds a CAN Bu s m essa ge r equ est t o t h e
E CM, t h en wa it s for t h e E CM r espon se. If t h e E CM
does n ot r espon d, t h e SKRE E M will sen d t h e r e-
qu est a ga in . If t h e E CM does n ot r espon d a ga in , t h e
SKRE E M will st op sen din g t h e r equ est a n d st or e a
t r ou ble code in m em or y. If t h e E CM sen ds a cor r ect
r espon se t o t h e SKRE E M, t h e SKRE E M sen ds a
va lid/in va lid key m essa ge t o t h e E CM. Th e E CM
will a llow or disa llow en gin e oper a t ion ba sed on t h is
m essa ge.
Secr et Key - a n elect r on ica lly st or ed va lu e (iden -
t ifica t ion n u m ber ) t h a t is u n iqu e t o ea ch SKRE E M.
Th e secr et key is st or ed in t h e SKRE E M, E CM a n d
a ll ign it ion key t r a n spon der s.
Ch a llen ge - a r a n dom n u m ber t h a t is gen er a t ed by
t h e SKRE E M a t ea ch ign it ion key cycle.
Th e secr et key a n d ch a llen ge a r e t h e t wo va r i-
a bles u sed in t h e a lgor it h m t h a t pr odu ces t h e
en cr ypt ed r espon se m essa ge. Th e t r a n spon der u ses
t h e cr ypt o a lgor it h m t o r eceive, decode a n d r espon d
t o t h e m essa ge sen t by t h e SKRE E M. Aft er r e-
spon din g t o t h e coded m essa ge, t h e t r a n spon der
sen ds a t r a n spon der ID m essa ge t o t h e SKRE E M.
3.3 DIAGNOSTIC TROUBLE CODES
E a ch dia gn ost ic t r ou ble code (DTC) is dia gn osed
by followin g a specific pr ocedu r e. Th e dia gn ost ic
t est pr ocedu r e con t a in s st ep-by-st ep in st r u ct ion for
det er m in in g t h e ca u se of t h e DTC a s well a s n o
t r ou ble code pr oblem s. It is n ot n ecessa r y t o per-
for m a ll of t h e t est s in t h is book t o dia gn ose a n
in dividu a l code.
Alwa ys begin dia gn osis by r ea din g t h e DTCs
u sin g t h e DRBIII . Th is will dir ect you t o t h e
specific t est (s) t h a t m u st be per for m ed.
3.3.1 HARD CODE
A DTC t h a t com es ba ck wit h in on e cycle of t h e
ign it ion key is a h a r d code. Th is m ea n s t h a t t h e
pr oblem is cu r r en t ever y t im e t h e E CM/SKRE E M
ch ecks t h a t cir cu it or fu n ct ion . P r ocedu r es in t h is
m a n u a l ver ify if t h e DTC is a h a r d code a t t h e
GEN ERAL I N FORM AT I ON
begin n in g of ea ch t est . Wh en t h e fa u lt is n ot a h a r d
code, a n in t er m it t en t t est m u st be per for m ed.
NOTE: If the DRBIII
multiple components (i.e. ECT, MAF, IAT
sensors) identify and check the shared
circuits
continuing (i.e. sensor grounds or 5-volt
supply circuits). Refer to the appropriate
schematic to identify shared circuits.
3.3.2 INTERMITTENT CODE
key t h e
A DTC t h a t is n ot cu r r en t ever y t im e t h e E CM/
SKRE E M ch ecks t h e cir cu it or fu n ct ion is a n in t er-
m it t en t code. Most in t er m it t en t DTCs a r e ca u sed
by wir in g or con n ect or pr oblem s. P r oblem s t h a t
com e a n d go like t h is a r e t h e m ost difficu lt t o
dia gn ose; t h ey m u st be looked for u n der specific
con dit ion s t h a t ca u se t h em . Th e followin g ch ecks
m a y a ssist you in iden t ifyin g a possible in t er m it -
t en t pr oblem .
– Visu a lly in spect t h e r ela t ed wir e h a r n ess con -
n ect or s. Look for br oken , ben t , pu sh ed ou t or
cor r oded t er m in a ls.
– Visu a lly in spect t h e r ela t ed wir e h a r n ess.
Look for ch a fed, pier ced or pa r t ia lly br oken
wir e.
– Refer t o h ot lin es or t ech n ica l ser vice bu llet in s
t h a t m a y a pply.
NOTE: Electromagnetic (radio) interference
can cause
malfunction. This interference can interrupt
communication between the ignition key
transponder and the SKREEM.
3.3.3 ECM DIAGNOSTIC TROUBLE CODES
IMPORTANT NOTE: Before replacing the
ECM for a failed driver, control circuit or
ground circuit, be sure to check the related
component/circuit integrity for failures not
detected due to a double fault in the circuit.
Most ECM driver/control circuit failures are
caused by internal failures to components
(i.e. relays and solenoids) and shorted
circuits (i.e. sensor pull-ups, drivers and
ground circuits). These faults are difficult to
detect when a double fault has occurred and
only one DTC has set.
If t h e DRBIII displa ys fa u lt s for m u lt iple com -
pon en t s (i.e. MAF, E CT, E NG OIL, et c.), iden t ify
a n d ch eck t h e sh a r ed cir cu it s for possible pr oblem s
befor e con t in u in g (i.e. sen sor gr ou n ds or 5-volt
3
displays faults for
for possible problems
an intermittent
before
system