EGR System

With engine stopped, visually inspect entire EGR system and clean as necessary. Replace hoses that are cracked or broken. Inspect EGR valve(s) for signs of binding or sticking by moving valve diaphragm upwards with finger.

Fig 1: 200SX EGR System
Courtesy of NISSAN NORTH AMERICA, INC.
With engine running, check operation of EGR valve(s) and thermal vacuum valve by placing finger on diaphragm of EGR valve and checking diaphragm movement.
With engine coolant temperature below "Closed" value, increase engine speed to 3000-3500 RPM (2000-2500 RPM on Pickup and 200SX). EGR valve diaphragm should remain closed.
With engine coolant temperature above "Open" value, increase engine speed to 3000-3500 RPM (2000-2500 RPM on Pickup and 200SX). EGR valve diaphragm should open and allow exhaust gas recirculation.
If EGR valve does not operate as indicated, disconnect EGR valve-to-thermal vacuum valve vacuum hose at EGR valve and air pipe line (200SX only).
Increase engine speed to 3000-3500 RPM (2000-2500 RPM on Pickup and 200SX). Check for vacuum at end of disconnected hose.

If vacuum is present, check EGR, VVT, thermal vacuum, and vacuum delay valves on Pickup, Sentra, 210 and 310. If vacuum is present, on all others, replace EGR valve(s). If vacuum is weak or not present, replace TVV.

THERMAL VACUUM VALVE SPECIFICATIONS

Application

Valve Closed Above °F (°C)

Valve Open Below °F (°C)

Maxima & 280ZX

⁽¹⁾

⁽²⁾

Pickup, Stanza & 210

140 (60)

Sentra & 310

122 (50)

200SX

104 (40)

⁽¹⁾	Between 131 (55) and 203 (95).

⁽²⁾	Below 131 (55) and Above 203 (95).