Hummer H1 (2002+). Manual — part 77
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Transmission/Transfer Case 5-107
®
05745159
9
1.
After the repair is complete, use the scan tool to
select “DTC,” then “Clear in fold function.
2.
Select “Specific DTC” and enter DTC “P1810.”
3.
Operate the vehicle under the following condi-
tions:
• Turn the ignition switch “on” for at least 2 sec-
onds. Then start vehicle, idle for 5 seconds, then
drive vehicle in D4 until converter clutch locks
for 20 seconds.
—
—
Repair veri-
fied, exist
DTC table.
DTC P1810 Pressure Switch Circuit Fault (Cont’d)
Step
Action
Value
Yes
No
5-108
Transmission/Transfer Case
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®
DTC P1811 Maximum Adapt and Long Shift
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.
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.
Automatic
Transmission
Fluid
Pressure
Manual Valve
Position
Switch
(TFP)
Trans
Range C
Input
Trans
Range B
Input
Trans
Range A
Input
C34
P
R
N
D
E
C
Rev
Switch
Lo
Switch
D2
Switch
D3
Switch
D4
Switch
C32-S
C32-H
C32-K
764 PP
763 DB
762 OR
C29-B4
C29-B5
C29-B6
A / T ISS
High
A / T ISS
Low
Tw i s t e d
P a i r
B
C32-A
B
A
Auto Trans Input Shaft
Speed Sensor
A/T ISS
C27-D1
C27-D11
495 DB
496 GY
POWERTRAIN
CONTROL
MODULE
(PCM)
FUSE 2A
10A
EXTERIOR
C33-F
351 PK
C34
D
C
S
B
A
M
L
C32-G
C32-F
C32-E
C32-D
C32-C
C32-J
C32-H
C34-E
C27-C15
C27-C7
C28-C5
C28-C6
C28-C4
C29-B12
C27-C9
265 LB
264 RD
924 TN
315 YL
237 LG
359 BK
923 BR
PRESSURE
CONTROL
SOLENOID
(PCS)
TORQUE
CONVERTER
CLUTCH
SOLENOID
(TCC)
1-2 SHIFT
SOLENOID
(1-2)
2-3 SHIFT
SOLENOID
(2-3)
TRANSMISSION
FLUID
TEMPERATURE
SENSOR
(TFT)
PCS
LOW
PCS
HIGH
TCC PWM
SOLENOID
CONTROL
2-3 SS
CONTROL
1-2 SS
CONTROL
SENSOR
GROUND
TFT
SENSOR
SIGNAL
POWERTRAIN
CONTROL
MODULE
(PCM)
HOT IN RUN
AND START
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Transmission/Transfer Case 5-109
®
05745159
Conditions For Clearing DTC
• The DTC can be cleared using the scan tool. The DTC
will be cleared from history when the vehicle has
achieved 40 warm-up cycles without reported failure.
• PCM will cancel DTC default actions when the fault no
longer exists and ignition is cycled “Off” long enough to
power down the PCM.
Diagnostic Aids
• Inspect wiring for poor electrical connections at the
PCM and the 20-way connector Look for possible bent,
backed out, deformed or damaged terminals. Also,
check for chafed wire that could short to bare metal or
other wiring. Inspect for broken wire inside the insula-
tion.
• When diagnosing a possible intermittent short or open
condition, move wiring while observing test equipment
for a reading change.
Test Description
The numbers below refer to the step numbers on the diagnostic
chart.
2. This step tests for low fluid level which can cause delayed
shifts.
3. This step compares the indicated range signal from the
Range Signal Chart to the Automatic Transmission Fluid Pres-
sure Manual Valve Position Switch (TFP Val. Position Sw.)
selected gear range.
5. This step tests for low line pressure, which can cause de-
layed and long shifts.
15. When DTC P1811 sets, the PCM commands maximum line
pressure and does not inhibit TCC engagement. High engine
speed and maximum line pressure can cause the Torque Con-
verter to “balloon”.
5-110
Transmission/Transfer Case
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®
DTC P1811 Maximum Adapt and Long Shift
Step
Action
Value
Yes
No
1
Was the Powertrain ON-Board Diagnostic (OBD)
System Check performed?
—
Go to
Step 2
Go to OBD
Powertrain
System Check.
2
Have you performed the transmission fluid checking procedure?
—
Go to
Step 3
Go to Transmis-
sion Fluid Check-
ing Procedure.
3
1.
Install the scan tool.
2.
With the engine OFF, turn the ignition switch to the RUN
position.
Important
: Before clearing the DTC’s, use the scan tool in order
to record the Freeze Frame and Failure Records for reference.
The Clear Info function will erase the data.
3.
Turn the ignition switch to the RUN position.
4.
Record the DTC Freeze Frame Failure Records and DTC’s.
Use the scan tool snapshot mode in order to record the shift
times.
Important
: If any other engine or transmission DTC’s are set, re-
fer to their respective diagnostic tables first.
5.
Select TFP sw. A/B/C on the scan tool.
6.
Start the engine and apply the brake pedal.
7.
Select each gear range: D1, D2, D3, D4, N, R, and P.
Does each selected transmission range match the TFP Sw. A/B/C
display on the scan tool? Refer to the Range Signal table.
—
Go to
Step 7
4
1.
Drive the vehicle in D4 in order to obtain a 1-2, a 2-3, and a
3-4 shift time.
2.
Using the scan tool, review the shift time information for 1-
2, 2-3, and 3-4 shift times.
Were all of the shift times above the specified value?
1-2, or 2-3
upshifts:
1.25 seconds
3-4 upshifts:
6.38 seconds
Go to
Step 5
Go to Step 8
5
Perform the line pressure test. Refer to Line Pressure Test.
Is the line pressure within specifications?
—
Go to
Step 6
Go to Symptom
Diagnosis Table,
Low Line Pressure
6
1.
Remove the transmission oil pan. Refer to Transmission Oil
Pan Removal, in 4L80-E On-Vehicle Service.
2.
Inspect the pan and the fluid for contamination.
Is there excessive contamination in the transmission oil pan?
—
Go to
Unit
Repair
Go to Step 7
7
Inspect the transmission for fluid pressure loss in one
of the following areas:
• Valve Body Gasket
• Forward Clutch Seals
• Turbine Shaft Seals
Refer to Unit Repair.
Did you find and correct a problem?
—
Go to
Step 17
—
8
Inspect the 1-2, 2-3, and the 3-4 adapt cells on the scan tool.
Were any of the upshift adapt cells at their maximum adapt limit?
—
Go to
Step 9
Go to Diagnostic
Aids
9
Did the 3-4 shift time exceed the specified value?
6.38 seconds
Go to
Step 12
Go to Step 10
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