Stratus L4-2.4L VIN X (1998)
EGR Backpressure Transducer: Testing and Inspection
The first part of this test will determine if the transducer diaphragm at the back-pressure has ruptured or is leaking. The second part of the test will
determine if engine vacuum (full manifold) is flowing from the inlet to the outlet side of the transducer.
NOTE: Electrical operation of the solenoid should be checked with the DRB scan tool before proceeding with the vacuum test.
1. Disconnect the rubber back-pressure hose from the fitting at the bottom of the transducer.
2. Connect a hand-held vacuum pump to this fitting.
3. Apply 10 inches of vacuum to this fitting.
4. If vacuum falls off, the transducer diaphragm is leaking.
5. Replace the transducer and EGR valve assembly. Connect the rubber hose to the transducer and proceed to next step for further testing.
6. Reconnect the hose to the EGR valve.
7. Remove the rubber hose at the vacuum inlet fitting on the EGR solenoid.
8. Connect a vacuum gauge to this disconnected hose.
9. Start the engine and bring to operating temperature. Hold engine speed at approximately 1,500 rpm.
10. Check for steady engine vacuum (full manifold) at this hose. If engine vacuum is not present, check vacuum line to engine and repair as necessary
before proceeding to next step.
11. Connect the hose to the vacuum inlet fitting on the solenoid.
12. Disconnect the rubber hose at the vacuum outlet hose on the transducer.
13. Connect a vacuum gauge to this fitting.
14. Disconnect the electrical connector from the solenoid. This will simulate an open circuit. A DTC will be set in the PCM that must be erased after
testing is complete.
15. Start the engine and bring to operating temperature.
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Hold the engine speed at approximately 2,000 rpm while checking for vacuum (full manifold) at this fitting.
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To allow full manifold vacuum to flow through the valve, exhaust back-pressure must be present at valve. It must be high enough to hold the
bleed valve in the transducer protion of the valve closed.
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Have a helper momentarily -- for a second or two -- hold a rag over the tailpipe opening to build some exhaust back-pressure while observing
the vacuum gauge. Heavy gloves should be worn.
CAUTION: Do not cover the tailpipe opening for an extended period of time as damage to components or overheating may result.
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As temporary back-pressure is built, full manifold vacuum should be observed at the outlet fitting.
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Without back-pressure, and engine at approximately 2,000 rpm, the gauge reading will be low. This low reading is normal.
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At idle speed, the gauge reading will be erratic. This is also normal.
16. If full manifold vacuum is not present at the outlet fitting, but was present at the inlet fitting, replace the transducer and EGR valve assembly.
Refer to EGR Valve Replacement.
NOTE: The EGR valve, valve control and attaching hoses are serviced as one assembly.
