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b. Vehicle has a 2-wire sensor:
While the engine is off determine which of the 2 wires has a low resistance between the wire and
the sensor body. This is the heater power for the sensor. Wire analog output 1 directly to the
other wire. Leave the heater power wire unconnected but make sure it cannot ground itself or see
above.
c. Vehicle has a 3-wire sensor:
Typically the 3 wires are: heater power, Ground, and sensor element connection.
Generally they have 1 black wire and 2 white wires. Connect the black wire from the EFI
computer to analog output 1 of the meter. Leave the other wires unconnected but make sure they
cannot contact any metal parts or see above. If the wiring colors are different, then heater power
can simply be determined by measuring the voltage on the wires when the engine is running. The
wire showing 12V or more is the heater power. The sensor element connection voltage fluctuates
around 0.45V when the car is warmed up. Wire analog output 1 directly to this wire. The Ground
connection has low resistance to chassis ground (less than 1 Ohm). Measure while the engine is
off.
d. Vehicle has a 4-wire sensor
Typically the 4 wires are: heater power, heater ground, sensor ground, and sensor element
connection. Proceed as for the 3-wire sensor.
Appendix A: LC-1 Cable Pinouts
A1. Sensor Interface Connector (Standard DIN-5 female)
Lambda Meter Signal Wire Colors
Bosch LSU4.2
1 Pump+ red
2 Sens+ black
3 Heater - white
4 Pump-/Sens- yellow
5 Heater + gray
