Hummer H1 Service Manual page 289

5-90 Transmission/Transfer Case
.
Step
1 1. Connect scan tool.
2. Turn the ignition switch to on.
NOTE: Important: Before clearing DTC(s), use the
scan tool to record "Failure Records" for reference, as
data will be lost when the "Clear Info" function is used.
3. Record the DTC "Failure Records."
4. Start engine and shift into Park.
5. Using the transmission output control function on
the scan tool, apply 0.1 amp through 1.0 amp while
observing "PC Ref. Current" and "PC Act. Cur-
rent."
Is the "PC Act. Current" reading always within the indi-
cated value?
2 1. Turn ignition off.
2. Disconnect transmission 20-way connector.
3. Install the 05743837 Jumper Harness on the trans-
mission side of the 20-way connector.
4. Using the multimeter and Connector Test Adapter
Kit, measure the resistance between terminals "C"
and "D."
Is the resistance within indicated values?
3 1. Remove transmission oil pan.
2. Disconnect wiring harness at PCS.
3. Measure resistance of PCS.
Is resistance within indicated values?
4 Replace the PCS.
Is the replacement complete?
5 Repair internal wiring harness for open.
Is the repair complete?
6 Inspect/repair circuits 264 and 265 for short to ground
or poor connections.
Was a problem found?
7 Replace PCM.
Is the replacement complete?
8 1. After the repair is complete, use the scan tool to
select "DTC," then "Clear Info" function.
2. Select "Specific DTC" and enter DTC "P0748."
3. Ensure the following conditions are met:
• The PCS duty cycle is not at its electrical high or
DTC P0748 Pressure Control Solenoid - Electrical
Action
low limit (short cleared).
_____________________________________________
Value
0.16 amp
3-7 ohms
3-7 ohms
Yes
Go to Diag-
nostic Aids
Go to Step 6
Go to Step 5
—
Go to Step 8
—
Go to Step 8
—
Go to Step 8
—
Go to Step 8
—
—
®
No
Go to Step 2
Go to Step 3
Go to Step 4
—
—
Go to Step 7
—
Repair veri-
fied, exit DTC
table.