Test reading, telematics unit (468)
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Test reading, telematics unit (468)
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The following pages include values and instructions for measuring signals and levels on the main instrument unit and its control module.
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Note the test conditions and use common sense when assessing the test result.
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First check that the control module has a power supply and is grounded.
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Then check all sensor inputs and signals from other systems.
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Finally, check the control module outputs. Remember that the test readings do not indicate whether the actuator is working.
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If any reading is not OK, consult the wiring diagram to trace the leads, connectors or components which should be checked more thoroughly.
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The specified test readings refer to those obtained with a calibrated Fluke 88/97.
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The test values %(+) and ms(+) indicate the pulse ratio and pulse duration of the signal. A test instrument capable of giving pulse ratio and pulse duration readings should be used. The (+) symbol indicates a positive trigger pulse, TRIG+.
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Control module connections
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K1
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Pin
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Component/Function
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In/Out
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Test conditions
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Across
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Test reading
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1-3
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No connection
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4
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Microphone +
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In
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Ignition ON
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4-5
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5.5 V
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5
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Microphone -
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In
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Ignition ON
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5-4
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5.5 V
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6-7
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No connection
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8
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Airbag + (OnStar)
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In
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Ignition ON
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8-B-
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0-1 V
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9
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SOS button (OnStar)
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In
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Ignition ON
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9-B-
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3.3 V
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10
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+30
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In
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Ignition ON
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10-B-
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B+
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11-19
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No connection
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20
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Ground
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In
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Ignition ON
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20-B+
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B+
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1 OPT
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Optic TX
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Out
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Signal cannot be tested
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2 OPT
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Optic RX
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In
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Signal cannot be tested
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K2
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Pin
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Component/Function
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In/Out
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Test conditions
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Across
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Test reading
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1
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GSM/AMPS antenna signal
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Signal cannot be tested
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2
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GSM/AMPS antenna ground
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Signal cannot be tested
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K3
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Pin
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Component/Function
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In/Out
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Test conditions
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Across
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Test reading
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1
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GPS antenna signal
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Signal cannot be tested
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2
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GPS antenna ground
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Signal cannot be tested
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K5
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Pin
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Component/Function
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In/Out
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Test conditions
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Across
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Test reading
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1
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Bluetooth antenna signal
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Signal cannot be tested
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2
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Bluetooth antenna ground
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Signal cannot be tested
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