Test readings, control module connections
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Test readings, control module connections
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The following pages contain values and instructions for obtaining readings of signals and levels on the heater.
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Note the test conditions and use your common sense when judging the test results.
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Unless otherwise stated, the test readings presented are with the ignition switch in the ON position.
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First check that the control module is supplied with current and 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 or not the actuator is in working order.
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If any reading is not OK, consult the wiring diagram to trace the leads, connectors or components which ought to be checked more thoroughly.
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The test readings given apply to a correctly calibrated Fluke 88/97.
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The readings %(+) and ms(+) indicate the pulse ratio and pulse duration. A test instrument capable of measuring both pulse ratio and pulse duration must be used. The + sign denotes a positive trigger pulse (TRIG+).
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> = greater than; < = less than;
»
= approximately equal to; ∼= alternating current
Pins with no additional comments have no pin connection. (LP = LOGIC PROBE; P = select pulse; p = perceptible pulses)
Pin
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Component/Function
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Input/Output
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Test conditions
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Across
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Test reading
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See
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1
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+30
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1-B+
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< 0.5 V
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2
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Ground
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2-B-
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< 0.1 V
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3
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MCC/ACC
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4
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Fuel pump
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Output
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4-2
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»
10 Ohm
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5
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No connection
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6
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Main relay, heater
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7
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No connection
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8
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No connection
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> = greater than; < = less than;
»
= approximately equal to; ∼= alternating current
Pins with no additional comments have no pin connection. (LP = LOGIC PROBE; P = select pulse; p = perceptible pulses)
Pin
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Component/Function
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Input/Output
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Test conditions
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Across
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Test reading
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See
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1
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Water pump +
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Output
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2
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Water pump -
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Output
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3
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Combustion air fan -
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Output
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4
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Combustion air fan +
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Output
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5
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Glow plug +
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Output
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5-6
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0,8 - 0,9 Ohm
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6
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Glow plug -
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Output
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5-6
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0,8 - 0,9 Ohm
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7
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No connection
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8
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No connection
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9
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Engine coolant temperature sensor 2
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Input
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9-10
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As in diagram
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10
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Engine coolant temperature sensor 2
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Input
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9-10
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As in diagram
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11
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Engine coolant temperature sensor 1
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Input
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11-12
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As in diagram
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12
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Engine coolant temperature sensor 1
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Input
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11-12
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As in diagram
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13
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Flame temperature sensor
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Input
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13-14
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As in diagram
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14
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Flame temperature sensor
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Input
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13-14
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As in diagram
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