Code 2-3-1 (Lambda Control Rich Or Lean In Part Load Range); Or Code 2-3-2 (Lambda Control Rich Or Lean At Idle)
- Control unit receives information from oxygen sensor on whether fuel/air mixture is too rich or too lean in part-load and idling ranges. Control unit adap-tive system compensates for this by making mixture leaner or richer as necessary. If mixture must be compensated excessively, a fault code is set.
- Start engine. Connect voltmeter between terminals No. 1 and 2 in starter motor 2-pin connector. Voltmeter should indicate battery voltage. If no voltage is present, check fuse No. 30.
- Stop engine. Disconnect starter motor connector. Connect ohmmeter between starter motor connector terminals No. 1 and 2. Ohmmeter should show 3-13 ohms, depending on resistor temperature.
- Connect Measuring Unit (999-3070 ) to ECU. See CONNECTING MEASURING UNIT TO ECU . Start engine. Connect voltmeter between terminals No. 28 and 30. After a short interval, voltmeter should oscillate between 0.1-1.0 volt.
- If voltage remains constant a zero volts, sensor is interpreting fuel/air mixture as lean. If voltage is constant at one volt, sensor is interpreting fuel/air mixture as rich.
- If either fault code 2-3-1 or 2-3-2 is displayed and voltmeter is oscillating between 0.1-1.0 volt, Lambda control is correctly adjusting CO content even though ECU is indicating fault.