Exhaust Gas Recirculation: Testing and Inspection

Fig. 58 Checking EGR control system circuit.:

1. Make a thorough visual check of system, wiping away oil as necessary to facilitate inspection. Replace any broken or cracked hoses and ensure that electrical connectors are securely connected.
2. With engine off, inspect EGR control valve and throttle chamber or body for any indication of binding or sticking by moving diaphragm/rod upward with vacuum pump.
3. On 1983 Maxima, check system circuit with voltmeter as shown,Fig. 58 If voltmeter readings are correct testing of system for 1983 Maxima is completed.
4. Start engine to check operation of EGR control valve and throttle valve. Place finger on diaphragm of EGR control valve to ensure that valve functions. Be careful that finger does not get caught between diaphragm and body of EGR control valve.
5. When engine coolant temperature is below 104°F, ensure that control valve does not operate and throttle valve is open when engine speed is raised from idle.
6. When engine coolant temperature is above 104°F, ensure that EGR control valve operates and throttle valve is closed at idle.
7. Slowly increase engine speed and ensure that throttle valve opens and EGR control valve then closes.
8. If EGR control valve operates and/or throttle valve is closed in step 5, check water temperature sensor.
9. If water temperature sensor appears normal, replace EGR control unit.
10. If EGR control valve and/or throttle valve do not operate properly in step 6, check them as follows:
a. Run engine at idle.
b. On 1982 Maxima and 1983 Sentra, disconnect harness connector at solenoid valve and check that EGR control valve operates normally and throttle valve closes normally. If they do not operate normally, check solenoid valves, EGR control valve, and throttle diaphragm independently. If they operate normally, check revolution sensor, potentiometer, and electrical circuits and, if they appear normal, replace EGR control unit.
c. On 1983 Maxima, disconnect harness connector. Apply battery voltage at yellow (+) and black(-) terminals to check throttle valve. Apply battery voltage at green and black (-) terminals to check that EGR control valve is half open. Apply battery voltage at green (+), white (+) and black (-) terminals to check that EGR control valve is fully open. If throttle valve and EGR control valve do not operate properly, check solenoid valves, EGR control valve and throttle diaphragm independently. If they operate normally, check revolution sensor, potentiometer and electrical circuits and, if they appear normal, replace EGR control unit
d. On 1984-86 Sentra disconnect electrical connector from solenoid valve, then apply 12 volts to connector and ensure EGR control valve operates normally and throttle valve closes normally.