Hummer H1 Service Manual page 307

5-108 Transmission/Transfer Case
DTC P1811 Maximum Adapt and Long Shift
Automatic
Transmission
Fluid
Pressure
Manual Valve
D2
Position
Switch
Switch
(TFP)
D4 D3
Switch Switch
D
P
C34
C32-H
C32-S
C29-B5
C29-B4
Trans Trans
Range C Range B
Input Input
Circuit Description
The Powertrain Control Module (PCM) compares the mea-
sured gear ratio to the known actual value. This allows the
PCM to determine the actual gear range of the transmission.
When an upshift is commanded, the PCM measures the inter-
val during which the gear ratio leaves the current range and
changes to reflect the commanded upshift. This interval is ex-
pressed on the scan tool as Shift Time. When this interval has
exceeded a predetermined limit, the PCM utilizes the shift
adapts to attempt to shorten the shift time.
If the PCM detects that the maximum allowable shift time has
been exceeded, and that the upshift adapts have reached their
upper limit, then DTC P1811 sets. DTC P1811 is a type D
DTC.
Auto Trans Input Shaft
Lo
Switch
Rev
Switch
E C
R N
C32-K
Tw i s t e d
C29-B6
Trans
Range A
Input
___________________________________________
TORQUE
CONVERTER
PRESSURE
CLUTCH
CONTROL
SOLENOID
SOLENOID
(TCC)
(PCS)
Speed Sensor
A/T ISS
D C
C34
A
B
C32-F
C32-G
P a i r C32-A B
C27-C15 C27-C7
C27-D1 C27-D11
PCS PCS TCC PWM
LOW HIGH SOLENOID
A / T ISS A / T ISS
CONTROL
High Low
POWERTRAIN
CONTROL
MODULE
(PCM)
Conditions For Setting DTC
• The engine must be running for greater than 5 seconds.
• One of the following conditions exists, with the adapt
cells at the maximum pressure allowed for 5 consecu-
tive occurrences of one shift.
- The 1-2 or the 2-3 upshifts are greater than 1.25
seconds.
- The 3-4 upshifts are greater than 6.38 seconds.
Action Taken When DTC Sets
• The PCM will default the transmission to maximum line
pressure.
• The PCM will freeze shift adapts.
HOT IN RUN
AND START
FUSE 2A
10A
EXTERIOR
C33-F
C34-E
1-2 SHIFT
SOLENOID
(1-2)
2-3 SHIFT
SOLENOID
(2-3)
S B A
C32-E C32-D C32-C
C28-C5 C28-C6 C28-C4
2-3 SS 1-2 SS
CONTROL CONTROL
POWERTRAIN
CONTROL
MODULE
(PCM)
®
TRANSMISSION
FLUID
TEMPERATURE
SENSOR
(TFT)
M L
C32-J C32-H
C29-B12 C27-C9
SENSOR TFT
GROUND SENSOR
SIGNAL