Problem with my 1997 CHEVY LUMINA
V6
CHECK ENGINE LIGHT
codes = EGR VALVE
work done to repair = REPLACED EGR VALVE, CODE WENT OFF FOR 1 DAY
OR 2
THEN CAME BACK ON
tech = JK
question = I HAVE A 97 CHEVY LUMINA, GAS TANK HAS A LEAK IN IT.
ANYTHING OVER 1/2 TANK DRIPS OUT. CHECK ENGINE LIGHT IS ON,
COMPUTER SAID EGR
VALVE NEEDED TO BE REPLACE. I REPLACED, LIGHT WENT OFF. 2 DAYS
LATER
LIGHT BACK ON. COMPUTER STILL SAYS EGR VALVE. COULD THE SMALL
GAS  LEAK BE
CAUSED FUMES TO SET OFF THE EGR VALVE SENSOR?







JK:
Probable cause for this code, assuming the wiring at the valve is good;
is a plugged EGR passage. There is a passage under the EGR valve that goes
into  the upper intake manifold, just beyond the throttle plate. This gets plugged
with  carbon, and does not allow the EGR to function properly, thus giving the
code.
CHEVY DASH WARNING LIGHTS
The exhaust gas recirculation (EGR) system is used to lower oxides of nitrogen (NOx)
emission levels caused by high combustion temperature. It does this by decreasing  
combustion temperature.

The main element of the system is the EGR valve. The EGR valve feeds small  
amounts of exhaust gas back into the combustion chamber. With the fuel/air mixture
thus diluted, combustion temperatures are reduced.

If a problem with the EGR system will not allow the PCM to control pintle position  
properly, DTC P0404 should set. The PCM also tests for EGR flow. If incorrect flow is
detected, DTC P0401 should set. See DTC list for other EGR codes.
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