Hummer H1 Service Manual page 280

____________________________________________
®
Step
1
Was the Powertrain On-Board Diagnostic (OBD) Sys-
tem Check performed?
2
Perform the Transmission Fluid Checking Procedure.
Refer to Transmission Fluid Checking Procedure.
Is the Procedure complete?
3 1. Install the scan tool.
2. With the engine OFF, turn the ignition switch to
the RUN position.
Important: Before clearing the DTCs, use the
scan tool in order to record the Failure Records for
reference. Using the Clear Info function erases the
stored Failure Records from the PCM.
3. Record the DTC Freeze Frame and Failure
Records, then clear the DTCs.
4. Start the engine.
5. Apply the parking brake, and select each transmis-
sion range: D1, D2, D3, D4, N, R, and P.
Does the scan tool TFP Switch A/B/C display match
each selected gear range? (Refer to the Range Signal
table).
4 1. Drive the vehicle in Reverse and D4.
2. Hold the vehicle speed above 11 km/h (7mph) for
greater than 2 seconds in the specified gear range.
3. Use the scan tool snapshot mode in order to record
the transmission gear ratio for each commanded
gear range: Reverse, 1st, 2nd, 3rd and 4th.
Are the gear ratios within the parameters for each spec-
ified gear range?
5 1. Connect the J–21867 Pressure Gauge to the trans-
mission line pressure tap.
2. Perform the Line Pressure Checking Procedure.
Refer to Line Pressure Check Procedure.
Is the line pressure within specifications for each
selected gear range?
6 1. Remove the transmission oil pan.
Refer to Changing the Fluid and Filter, in On-Vehi-
cle Service.
2. Inspect the oil pan and the fluid for contamination.
Did you find excessive contamination?
7 Inspect the transmission for the following problems:
• Sticking shift valves
• Stuck apply pistions
Did you find the condition?
05745159
DTC P0730 Incorrect Gear Ratio
Action
Transmission/Transfer Case
Value
–
Go to Step 2
–
Go to Step 3
–
Go to Step 4
Rev–2.04-2.12
1st–2.52-2.42
2nd–1.45-1.50
3rd–0.98-1.02
4th–0.73-0.77
Refer to Diag-
nostic Aids
–
Go to Step 6
Go to
Transmission
– Overhaul
Procedure, in
Unit Repair
–
Go to Step 10
5-81
Yes No
Go to Power-
train OBD
System Check
Go to Trans-
mission Fluid
Checking Pro-
cedure
Refer to DTC
P1810 TFP
Valve Postion
Switch CKT
Malfunction in
this section
Go to Step 5
Go to Step 8
Go to Step 7
Go to
Transmission
Overhaul
Procedure, in
Unit Repair.