EGR Valve Leakage Test
If the engine will not idle, stalls while idling or the idle is rough or slow, the poppet valve, located at the base of the EGR valve, may be leaking in the closed position.
Electric EGR Transducer Solenoid Test
NOTE: Before disconnecting any vacuum hoses, place an identification mark on each of them for correct installation.
- The engine should be OFF for the following test.
- Disconnect the rubber hose from the fitting at the top (vacuum motor) side of the EGR valve, and perform the following:
- Connect a hand-held vacuum pump to this fitting.
- Apply 15 in. (51 kPa) of vacuum to the pump, then observe the gauge reading on the pump.
- If the vacuum falls off, the diaphragm in the EGR valve has ruptured.
- Replace the EGR valve, as outlined later in this section.
NOTE: The EGR valve, valve control and attaching hoses are replaced as an assembly.
- Go on to the next step.
- A small metal fitting (backpressure fitting) is located at the base of the EGR valve. A rubber backpressure hose connects it to the backpressure fitting on the EGR valve control. Disconnect this hose from the EGR valve fitting.
- Remove the air cleaner inlet tube from the throttle body.
- Using compressed air from an air nozzle with a rubber tip, apply about 50 psi (345 kPa) of regulated air to the metal backpressure fitting on the EGR valve.
- By hand, open the throttle to the wide open position. Air should NOT be heard coming from the intake manifold while applying air pressure to the fitting.
- If air CAN be heard coming from the intake manifold, the poppet valve is leaking at the bottom of the EGR valve. Replace the EGR valve.
- Label, then disconnect each vacuum hose from the electric EGR transducer solenoid.
- Disengage the wiring harness connector from the transducer solenoid.
- Plug vacuum hose nipple A.
- Connect a hand-held vacuum pump to hose nipple B.
- Connect a positive pressure-type hand pump to hose nipple C.
Fig. 3: Testing apparatus arrangement for the electric EGR transducer solenoid
- Using 2 jumper wires, connect one between the transducer solenoid terminal and positive battery terminal, and the second wire to the remaining solenoid terminal.
- Connect and disconnect the second jumper wire to the negative battery terminal side, while applying vacuum and positive pressure to check airtightness. With vacuum applied, this test should produce the following results:
- Jumper wire disconnected and positive pressure not applied should produce a vacuum leak.
- Jumper wire disconnected and positive pressure applied should maintain vacuum.
- Jumper wire connected and positive pressure not applied should maintain vacuum.
Fig. 4: Measuring resistance between the solenoid terminals
- Using an ohmmeter, measure resistance between the transducer solenoid terminals.
- On 2.0L and 2.4L engines, the ohmmeter should read 25–35 ohms at approximately 68°F (20°C). On 2.5L engines, the ohmmeter should read 31–41 ohms at approximately 68°F (20°C).
- If the resistance measures out of specifications, replace the electric EGR transducer solenoid.