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Has anyone had an EGR Code P0406???

140K views 59 replies 29 participants last post by  Maxxheadroom 
#1 ·
I just got a check engine light this morning - Checked the code: P0406 - EGR Sensor A - Circuit High. Did a search - no luck. Just wondering if anyone has experienced this before, and if so - what's the fix? My warranty, it's expired - of course!

Thanks guys.
 
#2 ·
Hey, me too! Just the past couple of days. Mine first came on after I put in an FM modulator, so I just figured it was griping about having something disconnected, and it went out. Then I took the FM-mod back out (POS!) and it came back, I figured the same thing, it went out again. I'm hoping its just coincidence and I didn't do something (seems unlikely)

Now its back on again (when I actually checked it). Doesn't seem to be running any differently. Of course the manual is so helpful, 4 out of the 8 or so diagnostics require either the starscan or a goofy pinout box for the PCM. :(

I'll have to do the tests I can when I get a chance. Seems doubtful it'd hurt anything to let it go for a couple of days(?)
 
#3 ·
P0406-EGR Position Sensor Circuit High
  • When Monitored: With the ignition on. Battery voltage greater than 10 volts.
  • Set Condition: EGR position sensor signal is greater than 4.89. One trip Fault.
Possible Causes
(K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO (F856) 5-VOLT SUPPLY CIRCUIT
(K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
(K34) EGR POSITION SENSOR SIGNAL CIRCUIT OPEN
(K900) SENSOR GROUND CIRCUIT OPEN
EGR SOLENOID ASSEMBLY
PCM

most likely cause: EGR assembly
 
#12 · (Edited)
P0406-EGR Position Sensor Circuit High
  • When Monitored: With the ignition on. Battery voltage greater than 10 volts.
  • Set Condition: EGR position sensor signal is greater than 4.89. One trip Fault.
Possible Causes
(K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO (F856) 5-VOLT SUPPLY CIRCUIT
(K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
(K34) EGR POSITION SENSOR SIGNAL CIRCUIT OPEN
(K900) SENSOR GROUND CIRCUIT OPEN
EGR SOLENOID ASSEMBLY
PCM

most likely cause: EGR assembly
How many trips to clear? This came up on my 5.7L today.

Jay
 
#5 ·
2.7L EGR is located at the rear of the right cylinder head.


  1. EGR system components and location. Upper tube (2), EGR valve (1), and Lower tube (3).

here is the complete diagnostic procedure:

P0406-EGR POSITION SENSOR CIRCUIT HIGH



For a complete wiring diagram Refer to Section 8W[/B].

  • When Monitored:
  • With the ignition on. Battery voltage greater than 10 volts.
  • Set Condition:[/B] EGR position sensor signal is greater than 4.89. One trip Fault.
Possible Causes[/B] (K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO (F856) 5-VOLT SUPPLY CIRCUIT (K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE (K34) EGR POSITION SENSOR SIGNAL CIRCUIT OPEN (K900) SENSOR GROUND CIRCUIT OPEN EGR SOLENOID ASSEMBLY PCM
[/B]
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).[/B]
Diagnostic Test

1. EGR POSITION SENSOR VOLTAGE ABOVE 4.5 VOLTS [/B]

Start the engine.
With the scan tool, read the EGR Position Sensor voltage.

Is the voltage above 4.5 volts?
Yes
  • Go To 2
No
2. (K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO THE (F856) 5-VOLT SUPPLY CIRCUIT [/B]


Turn the ignition off.
Disconnect the EGR Solenoid harness connector.
Disconnect the PCM harness connectors.
Measure the resistance between the (K34) EGR Position Sensor Signal circuit and the (F856) 5-volt Supply circuit in the EGR Solenoid harness connector.

Is the resistance below 100 ohms?
Yes
No
  • Go To 3
3. (K34) EGR POSITION SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE [/B]


Ignition on, engine not running.
Measure the voltage on the (K34) EGR Sensor Signal circuit in the EGR Solenoid harness connector.

Is the voltage above 0 volts?
Yes
No
  • Go To 4
4. EGR SOLENOID ASSEMBLY [/B]


Turn the ignition off.
Connect the PCM harness connectors.
Connect a jumper wire between the (K34) EGR Position Sensor Signal circuit and the (K900) Sensor ground circuit.
With the scan tool, monitor the EGR Position Sensor voltage.
Ignition on, engine not running.

Is the voltage below 0.5 of a volt?
Yes
No
  • Go To 5
  • NOTE: Remove the jumper wire before continuing.
5. (K34) EGR POSITION SENSOR SIGNAL CIRCUIT OPEN [/B]


Turn the ignition off.
Disconnect the PCM harness connectors.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (K34) EGR Position Sensor Signal circuit from the EGR Solenoid harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?
Yes
  • Go To 6
No
6. (K900) SENSOR GROUND CIRCUIT OPEN [/B]


Measure the resistance of the (K900) Sensor ground circuit from the EGR Solenoid harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 30 ohms?
Yes
  • Go To 7
No
7. PCM [/B]

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?
Yes
No
 
#10 ·
not sure about USA but here in Canada, the only things covered by the extended emissions warranty are the catalysts and the PCM.

my check engine light just came on yesterday. went to auto zone and EGR came up on the test. does this have to do with gas? i just put some gas in my car about 10 minutes before the check engine light came on.
totally unrelated.
 
#13 ·
I think they get clogged up and stick. Mine was running pretty rough while I had the code, I tried to get the dealer to cover it under warranty but no go. I was past the 24k mark which seemed silly to me, its a failed part, no? Anyway, they wanted $340.... new valve($35) and clean throttle body($5). I just laughed them off...see you guys next time, I can do that myself, thanks. I actually wound up getting a used 1 from a member that did the EGR delete, funny thing was, his looked rougher than mine(rust and what not) but worked great. So, the cost was a $5 can of carb. cleaner for the throttle body and I paid shipping and through Nick a few extra bux for his troubles! Gotta love this place!! If you plan on doing this, just a heads up on the bottom mounting bolts, you'll need a small 10mm socket(1/4" inch short socket) and probably a longer one too, couple tight spots under there, but simple enough. I think some guys have even gotten away with removing the jammed EGR valve and knocking it loose...I didn't even bother. ANYWAY, I plan on an SRT header/exhaust upgrade and EGR delete, so I'll have a high milage but functional valve up for grabs(pay for shipping)
 
#14 ·
Cool, thanks. It went off after two drive cycles so I am just going to wait and see. A new one is $54 on rockauto.com

Jay
 
#22 ·
are you replacing just the valve of the vale and hose?

i just replaced mine a few months back. super easy -well except for one of the bottom bolts on the EGR itself.

1) remove 2 bolts holding the hose to the EGR.. the hose just gets pulled out of the throttle body with a gentle tug (theres a large rubber gasket in there that will give some resistance but just yank)
2) remove 2 bolts holding EGR to engine block-the one PITA is the bottom left, youll need a socket extension or a stubby wrench). careful not to drop the bolts down the abyss.
 
#16 ·
Got this code this morning- 200 miles from home and low on cash. Swell!
 
#18 ·
Couple of bolts on the front of the passenger side cylinder head for 5.7s. 112000 miles but hasn't happened....yet.
 
#21 ·
Thanks for all the info here guys!

I just got my Maggie back from the body shop after being rear-ended and put 40mi on it when the CEL came on...

I checked the code and got a P0406...

Ran to AutoZone and grabbed a new EGR Valve, Gaskets and a ratcheting 10mm wrench....

Had it installed in less than 30min and only cost $40!

So easy a Caveman could do it!
 
#23 ·
Thanks! I looked it over today, looks straight forward, but will probably take forever because that is how it goes for me.

Did anyone have any drivability issues? My CEL is out but I am getting some pretty noticeable surging and hesitation on light throttle under load, like a slight grade. Almost like a standard that needs to down shift a gear. MDS is off when this happens.

Jay
 
#24 ·
Did anyone have any drivability issues? My CEL is out but I am getting some pretty noticeable surging and hesitation on light throttle under load, like a slight grade. Almost like a standard that needs to down shift a gear. MDS is off when this happens.

Jay
Same here. The light went out for about a day, but is now back on. I'm now debating whether to replace the EGR valve, or just clean the old one and replace the gasket. Since I just got paid, I'll likely spring for the new valve...
 
#25 ·
I decided to shell out the $40 bucks at Auto Zone. It was a fairly straightforward replacement, except for the fact that I had to use five separate wrenches to get the four bolts out and back in...
 
#26 ·
drivability sucked for me before my swap. as you mentioned, i honestly thought the transmission wasnt shifting properly. most noticeable was under light load, and while cruising at highway speeds. i know i need a trans service (its just time) ...but those symptoms went away after the egr, gaskets, and hose replacement.
 
#36 ·
Thanks for the follow up. My CEL has not been on for about 10 days, and I have not changed it yet. My camshaft sensor did go bad and not it has been running great, so I am playing the waiting game. Glad to see you got it back to good!

Jay
I have those issue as noted in the 1st quote. I replaced my cam position sensor, runs much better. At 115k I think once I get the new EGR in it will be a lot better. No CEL's just never ran as smooth as I think it should.
 
#27 ·
Thanks for the follow up. My CEL has not been on for about 10 days, and I have not changed it yet. My camshaft sensor did go bad and not it has been running great, so I am playing the waiting game. Glad to see you got it back to good!

Jay
 
#28 ·
ya that part of it worked out well. installed it myself and saved a tonne of money. but now my axle boot managed to give itself a tiny pinhole and all the lube leaked out. im now grounded until i can scrounge up money for a new rear right axle.
 
#29 ·
Code P 0406 is on for me as well, I am getting the ssame symptoms you guys had.. Was going to go out today to buy the EGR valve.. what do I tell the clerk I'm looking for, just the EGR valve for a 05' Maggie R/T ??
 
#31 ·
Yes. Make sure he's looking it up for the 5.7, its totally different on the v6. Should come with a gasket too, and you wont need the tube if he asks.(copper tube) Also, when I tried to get the dealer to cover this under warr(didn't happen) the diagnosis was to clean the throttle body also. They wanted about $400 for the egr replace/TB cleaned.... I think it was a grand total of $5 for a can or carb cleaner, and I actually picked a member's used EGR for $10, and had the pleasure of laughing at the dealer, "I'm all set, thanks" ....dealer, "you'll need the code cleared!", me, "...yup, I got it." My original thought was for the $100 deductible it was worth it to have them do it and have a brand new 1, but, wasn't the case. 1 other thing, if you clean the throttle body, you'll need(or should) re-calibrate the throttle; simple, turn key to on, wait few seconds, slowly press the gas to the floor, slowly let it up, n thats it I believe
Ugh - I wish I had checked the price at the 'Zone first.
I was shocked myself. The guy that works here has a chally and said he gets a lot of stuff from rockauto also.
 
#32 ·
Just priced it... $85, I unplugged it for now, runs smooth. But in crappy tire, got in it and it wouldn't start the first try.. (fired up on the 2nd attempt)
 
#35 · (Edited)
A BWD EGR is $65 at advance with all gaskets needed. It took me 45 min from hood up to hood down on the magnum.

Double start condition for me was cleared by changing the cam position sensor.


Jay

Via Tapatalk
 
#38 ·
A BWD EGR is $65 at advance with all gaskets needed. It took me 45 min from good up to good down on the magnum.

Double start condition for me was cleared by changing the cam position sensor.

Jay

Via Tapatalk
Oh great, lol... What's the cam sensor cost ? Don't have advanced around here... (I just made an offer on a Predator to do the EGR delete)
 
#41 ·
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