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Neal, Pontiac Mechanic
Category: Pontiac
Satisfied Customers: 8351
Experience:  Experienced in most makes. Many years in family business.
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2001 Pontiac Bonneville SSEI: 3.8 Lt Supercharged V6..Vin..stall

Resolved Question:

Car: 2001 Pontiac Bonneville SSEI
Engine: 3.8 Lt Supercharged V6 (Engine Vin Code 1)
Mileage: 204000

When the car reaches operating temperature (200 degrees) running for maybe 35 minutes or so it starts to have idle issue. When moving slow or not moving at all the engine starts to pulse like its going to stall. Sometimes it does stall, and when I try to start it, it will start but then just die out if you dont rev the engine. You have to keep the engine reving above 1500 rpms or it will cut off. Sometimes it won't start at all after this. When on the highway it drives pretty good, but it has occassional power surges. After you get off the highway it will then have problems idling correct and want to cut off.

Things Ive Done:

I ran the codes and originally got a Mass Air Flow Sensor and EGR Valve (Closed) codes. I cleaned the Mass Air Flow sensor and that code went away. Then I replaced the EGR Valve, that code still comes up. I checked the hose going to it and it is not blocked with carbon. Even when the EGR valve closed code is cleared it will run and then come back on after the car has warmed up to operating temperature (200 degrees).

I have also replace the Throttle Position Sensor, Crankshaft Position Sensor, and Cam Shaft Position Sensor within the last 2 days. After doing this the car ran better but, then after running about 35 minutes it goes right back to the same problem. I have checked the fuel filter and all vaccum hose lines and they seem okay. I havent found and shorted or stripped wires to any of the sensors or spark plugs either.

Hope you can help

Submitted: 5 years ago.
Category: Pontiac
Expert:  Neal replied 5 years ago.

I'm Neal and I am here to assist you. Only accept when you are happy with my assistance. If I can't help I will open your Question to other experts.


So the only code is the egr code now?


What is the exact code?




This question will remain open and I will continue to work with you even after you accept. The question will remain active for 7 days after our last communication.

Customer: replied 5 years ago.

Yes, the only code I get is code P1404

Expert:  Neal replied 5 years ago.

It sounds like your problem is going ot be in the wiring or a bad connection at the pcm. Here is the info and diagnostic procedure if you want to try and track the issue down yourself.



The Powertrain Control Module (PCM) monitors the Exhaust Gas Recirculation (EGR) valve pintle position input to ensure that the valve responds properly to commands from the PCM. When the ignition switch is turned ON, the PCM learns the EGR learned minimum position. The PCM compares the EGR learned minimum position to the EGR position sensor when the EGR valve is commanded closed. If the EGR position sensor indicates that the EGR valve is still open when the PCM is commanding the EGR valve closed, this DTC will set.

The system voltage greater than 10 volts.

The EGR valve is enabled.

^ The EGR position sensor is 0.2 volts more than the EGR learned minimum position when the Desired EGR Position is commanded to 0 percent.
^ The above condition is present for 80 seconds.

^ The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

^ The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC "Last Test Failed" clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
^ Use a scan tool in order to clear the MIL and the DTC.

Inspect for the following condition:

Excessive deposits on the EGR valve pintle or seat Remove the EGR valve and check for deposits that may interfere with the EGR valve pintle extending completely or cause the pintle to stick.

If the problem is intermittent, refer to Intermittent Conditions. See: Computers and Control Systems > Initial Inspection and Diagnostic Overview > Intermittent Conditions






The numbers below refer to the step numbers on the diagnostic table:
2. This step verifies that the malfunction is present.
4. If DTC P1404 will only set under certain conditions, the malfunction may be intermittent. Refer to Diagnostic Aids. If an intermittent wiring problem is not present, test for a faulty connection at the PCM or the EGR valve. If the connections are OK and DTC P1404 continues to set, replace the EGR valve.

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