Hummer H1 Service Manual page 1138

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DTC P0238 - Turbocharger (TC) Boost Sensor Circuit High Voltage
Step
1 Important: Before clearing DTC(s) use the scan tool "Capture Info" to
record freeze frame and failure records for reference, as data will be lost
when "Clear Info" function is used.
Was the "On-Board Diagnostic (OBD) System Check" performed?
2 1. Scan tool connected.
2. Engine idling.
Does the scan tool display a Boost Pressure greater than or equal to the
specified value?
3 1. Turn the ignition "OFF".
2. Disconnect the Boost sensor electrical connector.
3. Turn the ignition "ON".
Does the scan tool display a Boost Pressure less than or equal to the speci-
fied value?
4 DTC is intermittent. If no additional DTCs are stored, refer to "Diagnostic
Aids". If additional DTCs are stored, refer to those chart(s).
Are additional DTCs stored?
5 1. Ignition ON, engine OFF>
2. With a J–39200 connected to ground, probe the 5 volt reference circuit at
the boost sensor harness.
Is voltage greater than the specified value?
6 1. Boost sensor disconnected.
2. Jumper the Boost sensor ground circuit at the harness with a test light
connected to B+.
Is the test light "ON".
7 Check the Boost sensor for a restriction.
Was a problem found.
8 Replace the faulty Boost sensor.
Is the action complete?
9 Check for a short to voltage in the Boost sensor signal circuit.
Was a problem found?
10 Check for a short to ground in the Boost sensor circuit.
Was a problem found?
11 Repair the Boost sensor circuit as necessary.
Is the action complete?
12 Replace the faulty PCM. Notice: If the PCM is faulty, the new PCM must
be programmed. Go to PCM replacement and programming procedures.
Is the action complete?
13 1. Using the Scan Tool, select "DTC", "Clear Info".
2. Start engine and idle at normal operating temperature.
3. Select "DTC", "Specific", then enter the DTC number which was set.
4. Operate vehicle within the conditions for setting this DTC as specified in
the supporting text.
Does the Scan Tool indicate that this diagnostic Ran and Passed?
14 Using the Scan Tool, select "Capture Info", "Review Info".
Are any DTCs displayed that have not been diagnosed?
05745159
Action
PCM/Tech 1 Scan Tool 73
Value(s) Yes
— Go to Step 2.
202 kPa Go to Step 3. Go to Step 4.
(4.8v)
9 kPa Go to Step 5.
— Go to the
Applicable
DTC table.
5.2v Go to Step 10.
— Go to Step 7. Go to Step 11.
— Go to Step 13. Go to Step 8.
— Go to Step 13.
— Go to Step 13. Go to Step 12.
— Go to Step 13. Go to Step 12.
— Go to Step 13.
— Go to Step 13.
— Go to Step 14. Go to Step 2.
— Go to the
applicable
DTC table
No
Go to OBD
System Check.
Go to Step 9.
Go to
Diagnostic
Aids.
Go to Step 6.
—
—
—
System OK.