Hummer H1 Service Manual page 298

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Step
1 1. Connect scan tool.
2. Turn the ignition switch on.
3. Record "Freeze Frame" and "Failure Records."
4. Start engine, apply brake pedal and shift into D1, D2, D3,
D4, N, R, and P.
Does each selected transmission range match "TR Switch" on
the scan tool?
2 1. Raise vehicle on twist that allows wheels to turn freely.
2. Start engine and shift into D4 range. Use scan tool to
command 1st, 2nd, 3rd, and 4th gears while increasing
engine speed.
Was 1st gear commanded and not achieved, or 4th gear com-
manded and other than 4th gear occurred? (Road testing the
vehicle may be necessary).
3 Check the shift solenoid/hydraulic circuit for:
• An internal malfunction.
• Damaged seals on shift solenoids.
Was a problem found and corrected?
4 1. After repair is complete, use scan tool to select "DTC,"
then Clear Info" function.
2. Select "Specific DTC" and enter DTC "P0756."
3. Operate the vehicle under the following conditions (only
if traffic and road conditions permit):
• PCM must see the proper gear ratio for each com-
manded gear for greater than one second in D1, D2,
D3, and D4. Hold the throttle at 25% and accelerate to
55 mph.
05745159
DTC P0756 2-3 Shift Solenoid Valve Performance
Action
Transmission/Transfer Case
Value
—
Go to Step 2
—
Go to Step 3
—
Go to Step 4
—
5-99
Yes No
Go to Pres-
sure Switch
Assembly
Resistance
Check
Go to Diag-
nostic Aids
—
Repair veri-
fied, exist
— DTC table.