Hummer H1 Service Manual page 308

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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".
05745159
Transmission/Transfer Case 5-109