SECTION 21 - TRANSMISSION 275
FAULT CODE F5 AND F6 / OPEN CIRCUIT
DIRECTION OUTPUTS
Direction selection related outputs (E06-Pin P,
E07-Pin N):
A short to plus is considered as a critical fault. Shorts
to plus usually result in being blocked in either For-
ward or Reverse. If both are on simultaneously, the
transmission Behaviour depends on the state of a
mechanical interlock inside the transmission.
In this case the Microprocessor normally turns on
the pressure modulator (E03-Pin T). This results in
immediate selection of neutral regardless of the ori-
gin of the fault. Indeed even in case the short to plus
is applied externally, this response effectively blocks
the transmission in neutral.
If however at the time the fault was detected a fault
was also present on the pressure modulator, the mi-
croprocessor reverts to shutdown mode and re-
mains this way until power is removed. Shutdown
mode is a state in which power is removed from the
microprocessor outputs by opening the internal re-
dundant shutdown path.
This only helps if the fault was caused by the micro-
processor internally.
Additionally, during program execution, critical vari-
ables are continuously checked for contents integri-
ty.
Gearshifts
low/high solenoid:
inactive = forward high is selected
active = forward low is selected
SHIFT
DIAGRAM -
SOLENOIDS
FORWARD REVERSE
1 2 3 4 1 2
reverse/n X X
forward/n
low/high X X X X
1st/2nd X X X
F28365
F
1234
12
Blinks Blinks
Blinks Faster
Blink
345678
NR T N
F4288
A
B
C
D
E
F
G
H
J
K
L
M
N
P
R
S
T
U
V
1 2
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