Hummer H1 Service Manual page 1076

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No Scan Tool Data
Step
15 1. Ignition "OFF."
2. Disconnect the PCM Connectors.
3. Ignition "ON."
4. Check voltage on the DLC connector (pin 2).
Is voltage at the specified value?
16 Reprogram the EEPROM and retest.
Is serial data present?
17 System OK.
18 Repair short to ground on the MIL control circuit.
19 Reprogram the EEPROM and retest.
20 1. Check fuse number 7.
2. If fuse is blown, repair short to ground in the battery
feed circuit to the DLC connector (pin 16).
3. If the fuse is OK, repair open in the battery feed circuit
to the DLC connector (pin 16).
21 Repair open in circuit that did not light the test light.
Refer to Section 12 for ground distribution.
22 Refer to Section 12 for cigar lighter repair.
23 Faulty Scan Tool and/or cable.
24 Repair short to ground in the serial data line.
25 Repair short to voltage in the serial data line.
26 System OK.
27 1. Check serial data line for an open.
2. If OK, check PCM and DLC connections.
3. If OK, replace the PCM.
NOTE: If the PCM is faulty, the new PCM must be
programmed. Go to PCM replacement and pro-
gramming procedures.
Is the action complete?
28 Replace the faulty PCM.
NOTE: if the PCM is faulty, the new PCM must be
programmed. Go the PCM replacement and pro-
gramming procedures.
Is the action complete?
05745159
Action
PCM/Tech 1 Scan Tool 11
Value(s) Yes
0v Go to Step 28
— Go to Step 26
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— Go to OBD
System Check
— Go to OBD
System Check
No
Go to Step 25
Go to Step 28
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