STEP 1. Check the heated oxygen sensor (rear).
(1) Disconnect heated oxygen sensor (rear) connector and connect test harness special tool, MB991658, to the connector on the heated oxygen sensor (rear) side.
(2) Measure the resistance between heated oxygen sensor connector terminal power supply line and terminal OHRL line.
(3) Standard value: 4.5 - 8.0 ohms [at 20°C (68°F)]
Is the measured resistance between 4.5 and 8.0 ohms [at 20°C (68°F)]?
Go to Step 2. Replace the heated oxygen sensor (rear). Then go to Step 8.