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System Functional Check

NOTE: To ensure proper operation of the EGR system all passages and moving parts must be free from plugging or sticking as a result of deposits. Clean or replace components and hoses as necessary.
  1. Warm engine to operating temperature. Attach a tachometer to the engine. Run engine at idle in Neutral an additional 70 seconds. Accelerate the engine abruptly to approximately 2000 RPM, but not over 3000 RPM.
  2. During this procedure, check the EGR valve stem for movement. Visible movement of the valve stem should occur. Repeat test to confirm operation. Movement of the stem indicates that the control system is functioning correctly.
  3. If EGR valve stem does not move, check for cracked, leaking, disconnected or plugged hoses. Verify correct hose routing. Disconnect hose harness from EGR valve/transducer and connect a vacuum pump to harness.
  4. Start engine and raise engine speed to 2000 RPM and hold. Apply 10 in. Hg vacuum to EGR while checking for EGR valve movement. If no movement occurs, replace EGR valve/transducer assembly.
  5. If valve opens approximately 1/8", hold vacuum constant and check for valve diaphragm leakage. Valve should remain open for at least 30 seconds. If leakage occurs, replace valve/transducer assembly. If valve is okay, check control system.
  6. If EGR valve stem did not move in step 2), but operates normally on external vacuum source, remove throttle body and check port in throttle bore for blockage. Use a solvent to remove deposits and check flow with light air pressure. Normal operation should be restored.
  7. If engine will not idle, or if engine stalls or idles very rough or slow, check for leaking EGR valve. With engine running, remove vacuum hose from EGR valve. If removing the vacuum hose does not correct rough idle, remove EGR valve/transducer assembly. Check valve for proper seating. Replace assembly as necessary.
  8. Also check EGR-to-intake manifold tube for leak. On 2.2L and 2.5L models, loosen tube and tighten to 25 ft. lbs. (34 N.m). On 3.0L models, remove tube and inspect gasket. Tube end should be uniformly indented on gasket, with no signs of leakage.
  9. If there are signs of leakage, replace gaskets and tighten flange nuts to 17 ft. lbs. (23 N.m). If leak persists, replace EGR tube and gaskets.
CHARGE TEMPERATURE SENSOR RESISTANCE

Temperature: °F (°C) Ohms
-40 to 20 (-40 to -7) 382,000-22,000
50-100 (10-38) 36,000-3300
140-245 (60-118) 3900-176
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