Exhaust Gas Recirculation: Testing and Inspection
SYSTEM INSPECTIONEGR Valve:
NOTE: Check condition of wiring harness, vacuum lines, and connectors before checking sensors or switches.
1. Start engine.
2. Accelerate engine and verify that EGR valve diaphragm does not move while engine is still cold.
3. Warm engine to operating temperature and run at idle.
WARNING: Use care when checking EGR valve; surrounding area is hot.
4. Accelerate engine and check that EGR valve diaphragm moves upward.
SOLENOID VALVE (EGR, VENT SIDE)
Fig. 153 Solenoid Vent Side:
1. Disconnect vacuum hoses.
2. Blow through vent hose and make sure air flows.
3. Disconnect valve connector.
4. Apply 12V and ground valve as shown.
5. Blow through vent hose and make sure air does not flow.
6. If not correct, replace valves.
SOLENOID VALVE (EGR, VACUUM SIDE)
Fig. 154 Solenoid Vacuum Side:
1. Disconnect vacuum hoses.
2. Blow through hose and make sure air does not flow.
3. Disconnect valve connector.
4. Apply 12V and ground to valve as shown.
5. Blow through hose and make sure air flows.
6. If not correct, replace valves.
EGR POSITION SENSOR RESISTANCE INSPECTION
EGR Position Sensor Connector Identification:
1. Disconnect sensor connector.
2. Check resistance between terminals as shown.
Terminals Resistance
A - B 5K ohms
A - C 0.7 - 5K ohms
B - C 0.7 - 5K ohms
EGR CONTROL VALVE
Checking EGR Valve:
1. Manually actuate the valve by pushing on the diaphragm with finger.
2. Check that the spring resistance is present and the diaphragm moves freely with no sticking or binding.
NOTE: Before replacing the EGR control valve, check the intake air and control systems.
Checking EGR Valve Operation:
3. Warm up the engine and run it at idle.
4. Connect a vacuum pump to the valve and apply vacuum.
5. Check that the engine runs roughly or stalls at more than 0-60 mmHg (1.6-2.4 in.Hg).
6. If not correct, replace the EGR control valve.
VACUUM CHAMBER
1. Disconnect the vacuum hoses from the vacuum chamber, and remove it.
Vacuum Pump Connection -- Vacuum Chamber:
2. Connect the vacuum pump to the vacuum chamber as shown.
3. Apply vacuum and check that no vacuum is held.
4. If not correct, replace the vacuum chamber.
Vacuum Pump Connection -- Vacuum Chamber:
5. Connect the vacuum pump to the vacuum chamber as shown.
6. Apply vacuum and check that vacuum is held
7. If not correct, replace the vacuum chamber.