LF CONTROL UNIT INSPECTION
2016 – MX-5 – Body and Accessories
LF CONTROL UNIT INSPECTION
1. Remove the scuff plate (RH). (See SCUFF PLATE REMOVAL/INSTALLATION.)
2. Remove the front side trim (RH). (See FRONT SIDE TRIM REMOVAL/INSTALLATION.)
3. Verify that the voltages of each of the terminals are as indicated in the terminal voltage table (reference).
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If the voltage is not as specified in the terminal voltage table (reference), inspect the parts under Inspection item(s) and related wiring harnesses.
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If the system does not work normally even though the inspection items or related wiring harnesses do not have any malfunction, replace the LF control unit. (See LF CONTROL UNIT REMOVAL/INSTALLATION.)
Terminal Voltage Table (Reference)
|
Terminal |
Signal name |
Connected to |
Measurement conditions |
Voltage (V) |
Inspection item (s) |
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A |
Request switch signal (RF) |
Request switch (RF) |
When request switch (RF) is pressed |
1.0 or less |
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When request switch (RF) is not pressed |
5.0 |
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B |
Power supply |
INTERIOR 15 A fuse |
Under any condition |
B+ |
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C |
Request switch signal (LF) |
Request switch (LF) |
When request switch (LF) is pressed |
1.0 or less |
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|
When request switch (LF) is not pressed |
5.0 |
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G |
Start stop unit signal |
Start stop unit |
Because this terminal is for communication, integrity determination using terminal voltage inspection is not possible. |
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|
H |
Keyless beeper power supply |
Keyless beeper |
When lock button on remote transmitter is pressed or front door request switch is pressed to lock |
Wave pattern (See Pattern 1.) |
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|
Except above |
1.0 or less |
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I |
Start stop unit signal |
Start stop unit |
Because this terminal is for communication, integrity determination using terminal voltage inspection is not possible. |
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J |
GROUND |
Keyless beeper |
Under any condition |
1.0 or less |
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K |
Keyless antenna (interior, front) |
Keyless antenna (interior, front) |
Because this terminal is for communication, integrity determination using terminal voltage inspection is not possible. |
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L |
GROUND |
Body ground |
Under any condition |
1.0 or less |
Body ground |
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M |
Keyless antenna (interior, front) |
Keyless antenna (interior, front) |
Because this terminal is for communication, integrity determination using terminal voltage inspection is not possible. |
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O |
Keyless antenna (exterior, LF) |
Keyless antenna (exterior, LF) |
Because this terminal is for communication, integrity determination using terminal voltage inspection is not possible. |
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P |
Keyless antenna (interior, rear) |
Keyless antenna (interior, rear) |
Because this terminal is for communication, integrity determination using terminal voltage inspection is not possible. |
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Q |
Keyless antenna (exterior, LF) |
Keyless antenna (exterior, LF) |
Because this terminal is for communication, integrity determination using terminal voltage inspection is not possible. |
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R |
Keyless antenna (interior, rear) |
Keyless antenna (interior, rear) |
Because this terminal is for communication, integrity determination using terminal voltage inspection is not possible. |
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S |
Keyless antenna (exterior, RF) |
Keyless antenna (exterior, RF) |
Because this terminal is for communication, integrity determination using terminal voltage inspection is not possible. |
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T |
Keyless antenna (interior, center) |
Keyless antenna (interior, center) |
Because this terminal is for communication, integrity determination using terminal voltage inspection is not possible. |
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U |
Keyless antenna (exterior, RF) |
Keyless antenna (exterior, RF) |
Because this terminal is for communication, integrity determination using terminal voltage inspection is not possible. |
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V |
Keyless antenna (interior, center) |
Keyless antenna (interior, center) |
Because this terminal is for communication, integrity determination using terminal voltage inspection is not possible. |
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W |
Keyless antenna (exterior, rear) |
Keyless antenna (exterior, rear) |
Because this terminal is for communication, integrity determination using terminal voltage inspection is not possible. |
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X |
Keyless antenna (exterior, rear) |
Keyless antenna (exterior, rear) |
Because this terminal is for communication, integrity determination using terminal voltage inspection is not possible. |
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Inspection Using an Oscilloscope (Reference)
Pattern 1
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LF control unit: H (+) ??? body ground (-)
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Oscilloscope setting: 2 V/DIV (Y), 100 ms/DIV (X), DC range