Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2002 Lexus SC 430FACTORY OEM SERVICE PROCEDURE
Diagnostic Trouble Code Chart
- DOOR ECU
Door ECU (driver's side, passenger's side)
DIAGNOSTIC TROUBLE CODE DEFINITIONSSAE code Item Diagnosis B1231 Driver's side jam protection limit switch malfunctions Power window regulator motor assembly LH open in limit switch system B1232 Driver's side jam protection sensor malfunctions Power window regulator motor assembly LH open or short in pulse sensor system B1233 Passenger's side jam protection limit switch malfunctions Power window regulator motor assembly RH open in limit switch system B1234 Passenger's side jam protection sensor malfunctions Power window regulator motor assembly RH open or short in pulse sensor system - TRANSPONDER KEY (IMMOBILISER) ECU
Immobilizer ECU
DIAGNOSIS CHARTSAE code Item Diagnosis B2780 Key unlock warning switch malfunctions Key unlock warning switch ON is not detected when the ignition switch is ON - MONITOR CODE NOTE:
- Monitor code shows the switch condition when a DTC is output.
- In case of that a code is indicated when the switch is not operated, it is detected that the switch is stuck.
In case of that a code is not indicated when the switch is operated, it is detected that the switch contact condition is bad.
DIAGNOSIS CHARTSAE code Item Diagnosis B1221 Driver's side switch 1 (operating) Power window switch of master switch or door unlock switch (for manual operation) is ON B1223 Passenger's side switch 1 (operating) Switch of the passenger's side regulator switch is ON
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.