Hummer H1 Service Manual page 1161

96 PCM/Tech 1 Scan Tool
DTC P0571 - Cruise Brake Switch Circuit
Step
1 Important: Before clearing DTC(s) use the scan tool "Capture Info"
Was the "On-Board Diagnostic (OBD) System Check" performed?
2 1. Scan tool installed.
2. Ignition "ON", engine "OFF".
3. Apply brakes.
Does scan tool display Cruise Brake switch "Closed" and then "Open" when
brake is released?
3 Apply brakes again.
Does scan tool display Brake switch "Closed" and then "Open" when brake is
released?
4 1. Ignition "ON", engine "OFF".
2. Stop lamp switch disconnected.
3. With test light connected to ground, probe normally open feed circuit (termi-
nal "B"). Is the test light "ON"?
5 1. Disconnect stop lamp switch.
2. Jumper normally open (terminal "A") feed circuit and the normally open sig-
nal circuits (terminal "B") together.
Does scan tool display Cruise Brake switch "Closed"?
6 1. Ignition "ON", engine "OFF".
2. Stop lamp switch disconnected.
3. With test light connected to ground, probe normally closed feed circuit (ter-
minal "F").
Is the test light "ON"?
7 1. Stop lamp switch disconnected.
2. Jumper normally closed (terminal "F") feed circuit and the normally closed
signal circuits (terminal "E") together.
Does scan tool display Cruise Brake switch "Closed"?
8 DTC is intermittent. If no additional DTCs are stored, refer to "Diagnostic
Aids". If additional DTCs are stored, refer to those charts(s) first.
Are additional DTCs stored?
9 Check normally open signal circuit (terminal "B") for an open or short to
ground.
Is action complete?
10 Check normally open Cruise Brake switch signal circuit for an open or short to
ground.
Was a repair performed?
11 Check normally open Cruise Brake switch signal circuit for a poor connection
at PCM.
Was a repair performed?
12 Check normally closed feed circuit (terminal "F") for an open or short to
ground.
Is action complete?
13 Check normally closed Cruise Brake switch signal circuit for an open or short
to ground.
Was a repair performed?
14 Check normally closed Cruise Brake switch signal circuit for a poor connection
at PCM.
Is action complete?
15 Replace stop lamp switch.
Is action complete?
_____________________________________________________
Action Value(s) Yes
— Go to Step 2.
— Go to Step 3.
— Go to Step 8.
— Go to Step 5.
— Go to Step 6. Go to Step 10.
— Go to Step 7. Go to Step 12.
— Go to Step 6. Go to Step 14.
— Go to
applicable
DTC table.
— Go to Step 17.
— Go to Step 17. Go to Step 11.
— Go to Step 17. Go to Step 16.
— Go to Step 17.
— Go to Step 17. Go to Step 14.
— Go to Step 17.
— Go to Step 17.
®
No
Go to OBD
System Check.
Go to Step 4.
Go to Step 6.
Go to Step 9.
Go to
Diagnostic Aids
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