Codes: PO471 / PO652?

[Kevin778]

I have 2015 RAM.

It is deleted and tuned, and I also did a 2nd Gen swap, so I do not have an exhaust pressure sensor.

The PO471 does not always come on, but it is annoying enough, and recently, the PO652 also came on.

I'm just looking for suggestions on what to look for so I can fix it.

Thanks.

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[sootmaster]

Here is a detailed write-up on codes.

When addressing codes recorded, these steps can help understand what power+ is to the sensor and return to ecu and signal return neg—side of sensors.

For example, it is low if you get a P0652 sensor reference voltage of 2 circuits.

You get a lovely CEL and the lightning bolt on your dash.

I experienced a loss of power and terrible fuel economy, and it wasn't enjoyable.

This truck is a 2018 and has 305k miles.

My issue turned out to be my EGR back pressure sensor.

What I did to narrow down my problem:

This is your 5-volt system, and everything from the EGR to the AC pressure is off this 5V power.

So you have three things that could be going wrong.
• Maybe you have a fault ECM- not very likely.
• you have a short in your wiring- damaged wiring.
• you have a bad sensor in your 5V wiring.

The obvious start would be to look at all of the wiring on the 5V system at the plugs to ensure nothing got stripped due to friction throughout your driving years.

Here's where you will locate all of your sensors; it would be best to focus on it.

• All the plugs going to the EGR
• EGR back pressure sensor
• MAP sensor
• A/C pressure sensor
• Fuel pressure sensor
• Cam position sensor

If all of the wiring Is fine- this is when you find a reference point for your voltage.

I used the EGR plug as my 5V reference.

Using my multimeter, I only got 0.19-0.20 volts. WEIRD.

I plugged up my tuner, and I got to work.

What I did was turned my ignition on and I started unplugging each sensor starting at the A/C pressure.

Once I unplugged it, I cycled my key and got a code on my tuner from the AC sensor.

This told me my sensor was still suitable.

I also measured the volts at the sensor plug and got 4.95.

I returned to my reference plug, which still showed 0.19-.020 volts.

I cleared my codes and still left P0652, so I moved on.

Did the same procedure on the following sensors.

• MAP sensor
• Fuel rail pressure sensor
• Cam position sensor

All of those sensors checked out the same as the A/C sensor.

When I got to the EGR back pressure sensor and unplugged it, I didn't get a code stating it was not plugged in.

I referred back to my 5v reference plug, which now reads 4.95 volts instead of 0.19-0.20

I plugged it back in, and it dropped my reference volts back down to 0.19-0.20.

My problem was my EGR back pressure sensor.

OREILLYS PART NUMBER - VP34

I installed the new sensor.

Once I plugged it i, the lightning bolt went away, and I could clear away my P0652 CEL.

I hope this helps you!

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[AK Bob]

I have 2015 RAM.

It is deleted and tuned, and I also did a 2nd Gen swap, so I do not have an exhaust pressure sensor.

The PO471 does not always come on, but it is annoying enough, and recently, the PO652 also came on.

I'm just looking for suggestions on what to look for so I can fix it.

Thanks.

The troubleshooting information for your trouble codes is attached.

I suspect you may have a 5V reference voltage shortened to ground.

Even though you no longer use some of these sensors, the connectors and wiring are still connected to the PCM.

Follow the steps in P0652 and check the wiring for any signs of damage.

The disconnected plugs should be cleaned, insulated, and sealed from the elements.

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[watersupply189]

Awesome writeup!


2016 Ram Laramie 3500, G56, 6.7, CC, 4x4

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[sootmaster]

This would pertain to all truck & vehicle years and engines.

To address this, parts replacement will never cure it if you do not test circuits and find unlaying harness issues.

I would love to THANK YOU, Ak-Bob, for adding the code pinpoint test.

Be sure to PAY close attention to POSSIBLE reasons and other areas that could trigger the code.

I see many trying to diagnose codes, but there is no actual area where they can read all inputs for any code you may get.

Thank you.

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