PGM-FI MIL 23 blinks (O2 sensor heater/California type only) (Honda VTX 1800 C, 2001-2008) [Engine and systems: Fuel and control system]

Turn the ignition switch to "OFF".
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Disconnect the O2 sensor 4P connectors. Check for loose or poor contact on the O2 sensor 4P connector.
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Connect the O2 sensor connector. Short the service check connector (page 5-6). Start the engine and check that the MIL blinks.	Does not blink →	Loose or poor contact on the O2 sensor 4P connector.
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23 blinks
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Turn the ignition switch to "OFF".
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Disconnect the O2 sensor 4P connector. Measure the resistance at the sensor side connector White terminals. Connection: White - White Standard: 10-40 Ω	Out of range →	Faulty O2 sensor.
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Normal
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Check for continuity White terminal and ground. Connection: White - Ground Standard: No continuity	Continuity →	Faulty O2 sensor.
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No continuity
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Turn the ignition switch to "ON". Measure the voltage at the O2 sensor wire harness side connector terminals. Connection: Black/white (+) - Black/green (-) Standard: Battery voltage	Normal →	Turn the ignition switch to "OFF". Disconnect the ECM 22P connectors.
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↓		Turn the ignition switch to "ON". Measure the voltage at the O2 sensor wire harness side connector terminals. Connection: Black/white (+) - Black/green (-) Standard: Battery voltage
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↓		Battery voltage: Open circuit in O2 sensor Black/green wires. No voltage: Replace the ECM and inspect again.
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Measure the voltage at the O2 sensor wire harness side connector terminal and ground. Connection: Black/white (+) - Ground (-) Standard: Battery voltage	No voltage →	Open circuit in the Black/white wire between the O2 sensor and engine stop relay.
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Battery voltage
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Turn the ignition switch to "OFF".
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Connect the O2 sensor 4P connectors.
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Disconnect the ECM connectors. Connect the test harness to the wire harness connectors.
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Measure the voltage at the test harness terminals. Connection: В2 (+) - А16 (-) Standard: Battery voltage	No voltage →	Open circuit in the Black/green wire between the ECM connector and Ог sensor 4P connector.
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Battery voltage
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Replace the ECM and inspect again.

PGM-FI MIL 23 blinks (O2 sensor heater/California type only) (Honda VTX1800C)