EG-423 ENGINE — 2JZ-GE ENGINE TROUBLESHOOTING 3 Check voltage between terminals HT1, HT2 of engine control module connector and body ground. SST ECM B 73, 72 HT1 HT2 FI6890 P C Warm up engine to normal operating temperature. Measure voltage between terminals HT1, HT2 of engine control module connector and body ground. when engine is idling and racing at 4,000 rpm. OK Voltage Idling 0 V Racing at 4,000 rpm 9 - 14 V Hint In the 4,000 rpm racing check, continue engine racing at 4,000 rpm for approx. 20 seconds or more. NG Check and replace engine control module. OK Replace main heated oxygen sensor.* *: It is probable the oxygen sensor has deteriorated. Usually, this cannot be confirmed by visual inspection. Reference INSPECTION USING OSCILLOSCOPE Ox Signal Waveform 1 V 0 V 200 msec./Division • With the engine racing (4,000 rpm) measure waveform between terminals OX1, OX2 and E1 of engine control module. HINT: The correct waveform is as shown, oscillating between approx. 0.1 V nd 0.9 V 1 V 0 V 200 msec./Division If the oxygen sensor has deteriorated, the amplitude of the voltage will be reduced as shown on the left. FI6514 FI6515