Control
Models up to 1988
1. The oxygen sensor is installed in the exhaust manifold. Disconnect the sensor connector.
2. Start the engine and set the mode to 3000 rpm. Wait 2 minutes.
3. Raise the RPM to 4000 and quickly close the throttle four or five times.
4. Increase the rpm to 5000, reset to 2000 and turn off the ignition. Quickly measure the voltage between the sensor connector and "weight": it must be below 0.4 volts
Pic. 3.4 When checking the oxygen sensor, use a digital voltmeter
5. Disconnect the MAP sensor vacuum hose from the throttle body and connect the vacuum pump. Apply vacuum and measure the voltage again. It must be greater than 0.6 volts.
6. If steps 4, 5 are not met, replace the sensor.
Models since 1988
7. Turn off the ignition.
8. Remove the fuse "HAZARD" in the fuse panel (see chapter 12) for 10 seconds to reset the EMU memory.
9. Check the fuel pressure in the system (see chapter 4).
10. With normal fuel pressure, start and warm up the engine.
11. Block the rear wheels and set the parking brake. Raise the front of the car and place it on stands.
12. Engage second gear and let the engine run for 15 minutes at 2000 rpm. Do not close the throttle during operation!
13. If the indicator lights up "CHECK ENGINE" or code 1 will be displayed on the EMU, check the connection "mass" wires on the thermostat housing and a contact in the oxygen sensor connector.
14. Disconnect the oxygen sensor connector and measure the voltage between the sensor contact and "weight" (see fig. 3.4).
15. Warm up the engine to operating temperature, then run the engine at 4000 rpm for 10 seconds and return to idle. The voltage at the sensor at 4000 rpm should be 0.6 volts and drop to 0.4 volts during deceleration to idle.
16. If the voltage is too high or low, replace the sensor.
17. If the sensor test gave a positive result, but the error code is still on, contact a service station.
Replacement
Attention: even with the ignition off, the cooling fan can turn on at any time - disconnect the negative cable from the battery.
18. Disconnect the sensor electrical connector.
19. Turn out the gauge.
20. Apply some non-stick paste to the threads of the new sensor and install it in the exhaust manifold.
21. Connect an electric socket.