Hummer H1 Service Manual page 1149

84 PCM/Tech 1 Scan Tool
DTC P0370 - Timing Reference High Resolution
Step
9 1. Turn the ignition OFF.
2. Disconnect the PCM.
3. Check the high resolution signal circuit for and open, short ot ground, or
short to the sensor ground circuit.
4. If the high resolutin signal circuit is open or shorted to ground, repair as
necessary.
5. Was the high resolution signal circuit open or shorted to ground?
10 Check the high resolution signal circuit for a poor connection at the PCM
and replace terminal if necessary.
Did the terminal require replacement?
11 Replace the injection pump.
Important: If injection pump is malfunctioning, the new injection pump
must be timed.
Is the action complete?
12 Replace the PCM.
Important: The new PCM must be programmed.
Is the action complete?
13 Replace the electrical harness filter.
Is the action complete?
14 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.
Does the Scan Tool indicate that this diagnostic Ran and Passed?
15 Using the Scan Tool, select "Capture Info", "Review Info".
Are any DTCs displayed that have not been diagnosed?
_____________________________________________________
Action Value(s) Yes
— Go to Step 14. Go to Step 11.
— Go to Step 14. Go to Step 12.
— Go to Step 14.
— Go to Step 14.
— Go to Step 14.
— Go to Step 15. Go to Step 2.
— Go to the
DTC table
®
No
—
—
—
System OK.