RPMs do not rise above 3,200, codes P0406 and P0499

Tiny
MALLYBOY
  • MEMBER
  • 2004 DODGE CARAVAN
  • 3.3L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 93,400 MILES
I began to notice that when I depress the throttle pedal way down, instead of the RPMs to reach 4 000 RPMs at wide-open throttle-angle before it snooze, it will stop at 3,200 RPMs and begins to snooze. I diagnosed it and pick P0406 and P0499. What could be the reason why it doesn't reach wide open throttle?
Wednesday, September 1st, 2021 AT 3:45 AM

16 Replies

Tiny
KASEKENNY
  • MECHANIC
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More than likely the EGR issue is causing the PCM to not keep the air fuel mixture correct so the engine is bogging down.

Here are a couple issues that help with low power issues. Due to you having the EGR code, I would start with running through this testing.

https://www.2carpros.com/articles/symptoms-of-low-engine-power

https://www.2carpros.com/articles/engine-has-low-power-output

What I suspect is happening is the EGR is stuck open or closed and this is causing the PCM to alter the air fuel which makes it bog.

One way to confirm this is to monitor the o2 sensor data when this is happening. I bet they are getting rich and it causes it to bog.

I am attaching the info from the manual below so let's run through this and see if we can confirm this.

Let us know if you have questions. Thanks
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Thursday, September 2nd, 2021 AT 6:06 PM
Tiny
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I have check the EGR sensor using multimeter to check resistance using diagram, terminal 1, 2 and 3 has no continuity but terminal 4 an 6 has continuity. Meaning that it has internal failure. I also check voltage on terminal 1and2 it reads: terminal1:05.02volts and terminal2: 05.06volts but I haven't check NVLD. So I need to change it.
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Thursday, September 2nd, 2021 AT 11:00 PM
Tiny
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I am not sure I follow your testing because you are checking the resistance from the 5 volt supply to the signal wire pin 1 and 2 and you have no resistance?

Then you are checking 2 and 3 and have no resistance? If so, then yes it appears there is an open in the sensor. Thanks for that info.
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Friday, September 3rd, 2021 AT 11:16 AM
Tiny
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Then you are checking 2 and 3 and have no resistance? Yes I check resistance on the 1 and 3. Also check on 2 and 3, there was no resistance. Then I checked on 6 and 4, there was resistance.
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Friday, September 3rd, 2021 AT 12:46 PM
Tiny
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Okay. Looking at the wiring diagram, pin 4 and 6 are connected inside the solenoid as signal and ground. The connection between 2 and 3 should be there as well as that is a solenoid connection and pin 1 is the signal wire to the PCM on the position of the EGR. So that should be connected but is not as critical as 2 and 3.

When these circuits are connect as I am stating that means they would have resistance. If your meter is reading OL or 0 then this means there is infinite resistance or an open circuit.
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Saturday, September 4th, 2021 AT 8:17 AM
Tiny
MALLYBOY
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What I suspect is happening is the EGR is stuck open or closed and this is causing the PCM to alter the air fuel which makes it bog.

One way to confirm this is to monitor the o2 sensor data when this is happening. I bet they are getting rich and it causes it to bog. I have checked O2 sensor data, I attached the picture of the live data below. There was no O2 activity from short term fuel trim to long term.
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Saturday, September 4th, 2021 AT 10:23 AM
Tiny
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That is due to a scan tool or PCM/sensor issue. If this was a PCM/sensor issue then you should have codes pointing to the o2 sensors.

So that means I suspect you have a scan tool issue that is not able to monitor that data. That is pretty common on generic scan tools. Do you see something in there that says o2 sensor voltage?

If you have the voltage we can get the same info. Basically the o2 sensor will tell the PCM a voltage between.01 and.1 volts. Based on this voltage we can tell if it is rich or lean.

Most all scan tools can get that voltage so let us know about this and we can figure that part of it out. Thanks
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Saturday, September 4th, 2021 AT 7:06 PM
Tiny
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To answer your question about seeing something in there that says o2 sensor voltage?
Yes, I saw it. I attached the picture below.
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Sunday, September 5th, 2021 AT 3:05 AM
Tiny
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Yep. I think you are right. More than likely that EGR is stuck open. This shows that the mixture is lean. The lower the voltage the leaner the mixture. If it is close to.2 that is lean. Then.9 volts is rich.

The odd thing in this though is that your upstream sensor is lower then the downstream sensor. That tells me we may have an issue with the sensors as well. Basically that is telling us that there is more fuel after the converter then before it. The point of the converter is to reduce the emissions so I am surprised that we don't have a cat inefficiency code as well. The fact that we don't makes me concerned this is a scan tool issue as well.

However, let's address the EGR since we have codes for that.
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Sunday, September 5th, 2021 AT 8:17 AM
Tiny
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The odd thing in this though is that your upstream sensor is lower than the downstream sensor. Does it mean that upstream sensor should be greater than downstream on normal operating condition? If yes, what if I interchange downstream sensor to upstream position. And upstream sensor to downstream position. Would correct anything?
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Sunday, September 5th, 2021 AT 10:26 AM
Tiny
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Your thinking is correct but no it would not correct anything. If they are not reading correctly then it doesn't matter what position they are in, they will not give the PCM correct info. So it may change the issue but it will not fix things. Plus the upstream and downstream sensors are normally different. They have different part numbers so more then likely you will set other codes if you swap them.

Again this is assuming the scan tool is reading them correctly as I would expect you to have a cat inefficiency code with these numbers.
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Monday, September 6th, 2021 AT 6:31 AM
Tiny
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I used another Scan tool Bluedriver to read the O2 sensor voltage. I notice that as the engine temperature increases, the readings get lower. I attached the pictures below.
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Monday, September 6th, 2021 AT 6:36 AM
Tiny
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Okay. That is better. However, they are very low showing a lean condition. So we have additional air getting into the system or a fuel issue but with this EGR issue, I suspect you were correct that it is stuck open just dumping exhaust back into the intake leaning it out.
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Monday, September 6th, 2021 AT 6:39 AM
Tiny
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Again! How would I check resistance on NVLD using multimeter as it also displayed code:P0499? Is it on Pin1 and Pin3?
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Monday, September 6th, 2021 AT 6:56 AM
Tiny
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If I am sensing frustration from you toward me, I am not sure why. I don't see anywhere in this thread where you asked how to do that test. I provided the testing for both of these codes in my first response to you. The last page gives specific steps on how to test the resistance of the NVLD.

You are to measure the control side which is pin 2 and 3. Then means for an open to ground. I attached the wiring diagram again below for you to review.
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Monday, September 6th, 2021 AT 4:05 PM
Tiny
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Okay! Thank you so far.
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Monday, September 6th, 2021 AT 9:56 PM

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