Hummer H1 Service Manual page 274

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Step
3
1. Turn the ignition OFF.
2. Disconnect the OSS Sensor connector from the
OSS Sensor.
3. Connect a J– 39200 DVOM (covered in Electrical
Section 12) on AC Voltage scale between terminals
A and B at the OSS Sensor.
4. Turn the ignition to the RUN position, and start the
engine.
5. Place the transmission in D3 range.
6. With the wheels rotating, slowly accelerate to 2000
engine RPM and hold.
Does the voltage drop or fluctuate at 2000 RPM?
4 1. Turn the ignition OFF.
2. Reconnect the OSS sensor harness to the sensor.
3. Disconnect the VSS Buffer Module harness con-
nector from the component.
4. Turn the ignition ON and turn the engine OFF.
5. Set the J– 39200 DVOM on AC volts.
6. Connect the J– 39200 DVOM between terminals 7
and 12 of the VSS Buffer Module harness connec-
tor.
7. Start the engine.
8. Place the transmission in D3 range.
9. With the wheels rotating, slowly accelerate to 2000
engine RPM and hold steady.
Does the voltage drop or fluctuate at 2000 RPM?
5 Inspect circuit 821 and circuit 822 for an intermittent
Did you find a problem?
6 Inspect circuit 821 and circuit 822 for an intermittent
short together or a short to ground.
Did you find a problem?
7 With the engine OFF, turn the ignition switch ON.
Select DC volts, and inspect for ignition voltage at ter-
minal 9 of the VSS Buffer Module harness.
Is the voltage greater than the specified value?
8 Repair the intermittent open or high resistance in circuit
39.
Is the repair complete?
9
1. Connect the J– 39200 DVOM between terminals 8
and 9 of the VSS Buffer Module harness connector.
Set the DVOM on DC volts.
2. Turn the ignition to the Run position.
Is the voltage greater than the specified value?
10 Repair the open or high resistance in circuit 451.
Is the repair complete?
05745159
DTC P0723 Output Speed Sensor Intermittent (Cont'd)
Action
Transmission/Transfer Case
Value
—
Go to Step 17
Above 0.5 volts
AC
Go to Step 5
__
Go to Step 12
__ Go to Step 12
10.5 volts DC
Go to Step 9
__
Go to Step 21
10.5 volts DC
Go to Step 11
__
Go to Step 21
5-75
Yes No
Go to Step 4
Go to Step 7
Go to Step 6
__
Go to Step 8
__
Go to Step 10
__