EGR trouble codes P040B and P2457 Fixed!

I have a 2008 Sprinter 3 liter V6 144" wheel base with 52,000 miles. My UltraGauge scanner started showing 2 trouble codes: P040B was EGR Sensor B Circuit Hi and
P2457 was EGR cooling system performance. Finally the check engine symbol went on. However, everything continued to run fine. Both trouble codes were fixed by replacing the rear temp. sensor.

There are two EGR temp. sensors. They both look the same (see 1st photo) but they are not. One is located in front near the oil dip stick (see 2nd photo) and the other is in the rear, but you can hardly see it from under the hood or from under the truck. (see 4th photo) which is pointing to it from under the hood.

I removed the front sensor, cleaned it with brake cleaner and the trouble codes did not change. So I purchased a new sensor from ebay part # 68012052AB for $128, thinking it was the front sensor because their picture look like the one it took out.

When I got the new sensor the electrical plug end would not fit in the front. It was configured different. (see 3rd photo) for front plug. Notice the slot is off to the side and it is black. Now (see 4th photo) notice the slot is in the middle and it is white. I found out that I had purchased a rear temp. sensor. I installed it in the rear and trouble codes went away!

The rear temp sensor is on the exhaust pipe in front of the catalytic converter. You can barely see the top angle of it. It is removed by feeling for it from under the van and using a 17 mm open end wrench to loosen the nut.

I hope this fix helps someone. I do appreciate the forum.

It could be that just cleaning the rear EGR temp. sensor would have worked to solve the problem. I did not try that.

2009 Freightliner Diesel, Passenger Van (built in Dusseldorf facility and shipped as a completed vehicle to US)
I am NOT nearly as savvy as "Deancm" aka Mr. Fix It -- and had to rely upon an MB dealer to "nail me" -- OOPS -- I mean resolve my P040B issue.

The FIX in my instance was the Outside Temp Sensor. Noted on the repair invoice as 007-542-13-18 with a part charge of $32.63.
They also charged me a diagnostic fee of $169 -- plus a "supplies" cost of $16.90. TOTAL CHARGES: $218.53 plus tax. OUCH!

Dean, Nice write up. Great text with details and excellent pics too.

How's the new rear sensor treating that CEL code after 2 1/2 mths? My '08 MB/Sprinter NCV3 chassis w 40k mi has been throwing those codes off/on for 5mths. I've been living in a mess between the last few days of my EGR warranty and delays from the dealer to replace it until I'm now 8wks out of warranty. I've been all over those sensors with cleaner until they look like new (including the EGR valve) with continued P040 CEL codes. After my last visit to the dealer when they reset the CEL yet again they said I needed to just replace the "defective" upper sensor at $135 on my dime because they denied it was under warranty as an EGR part.


For the life of me I can't see any correlation with an EGR CEL and Bucket lists fix with that outside air temp sensor. Sounds like he's been using my dealer who resets the code and finds a part to blame it on rather than hit the target problem. Hope his issue is truly solved, along with yours.

The consensus from those in the know on this site seems to be that my cooler is probably fouled too, causing a restriction that won't pass this soot effectively. Still searching for reliability in my recently purchased Sprinter.

Thanks for any updates. Mike

Landyacht said:

Dean, Nice write up. Great text with details and excellent pics too.

For the life of me I can't see any correlation with an EGR CEL and Bucket lists fix with that outside air temp sensor. Sounds like he's been using my dealer who resets the code and finds a part to blame it on rather than hit the target problem. Hope his issue is truly solved, along with yours.

Thanks for any updates. Mike

Click to expand...

+2 ^^^^^^^^^^^^^^
Think bucket list will be back at the dealer for another $169 fee

My EGR sensor replacement update:

NO GO for me. P040B CEL returned after only 300mi...... as expected because the cooler is probably fouled. It was joined by a P0676(?) glow plug warning light that comes and goes. Probably an unrelated issue with the Glowplug warning but I'm mystified by the endless variety of codes this beast is showing. Oh yeah, the transmission has also started doing the downshift rumble/shuddder between 2nd and 1st too. Joy.

Seems like I have two choices on my EGR code. Clean/replace the sensors/EGR valve/Swirl valve/cooler to keep it stock ($2500-$3500?) or buy a $600 Eco-tune and bypass all the hypersensitive emissions sniffers entirely.

That leaves me with the Glow plug and transmission gremlins to eject..... so far. Just sayin'. Mike

Late follow up to my troubles for those who find this in a search. Last year I reluctantly did the Green Diesel eng re-tune and rather shockingly it definitely solved my EGR and temp sensor fouling AND boosted my torque just as it promised. If you search my profile for other posts you'll find my input on other threads but suffice to say that I fixed my MB mess by doing the very easy (after paying $600 price tag) re-tune. It's been a year and the GDE re-tune has been the best money I've spent. Just do it if it'll work on your model year chassis.

As for the Glow plugs..... well eventually 5 of 6 failed and I replaced them after much cussing and knuckle busting (actually only about 4hrs). Between the retune to disable the EGR and Ekas valves and replacing the GPs my CEL is now OFF for the first time since shortly after buying the Sprinter. We'll see how long that lasts .

Feel free to email or PM if you have issues or questions. Happy to save you from my CEL drama. Fair winds, Mike

Hi Deancm. My problems with the P040B & P2457 codes have re-emerged. So, will try and follow your excellent post and see if that RESOLVES my issue(s). My Sprinter only has 46,000 miles on it. If that doesn't work, then the Green Engine engine re-tune (what is that?) may be the next step. I really don't like the Sprinter dealership service department in my area and try avoiding them as much as possible. ANy advice would be greatly appreciated.

DoingTheBucketList said:

Hi Deancm. My problems with the P040B & P2457 codes have re-emerged. So, will try and follow your excellent post and see if that RESOLVES my issue(s). My Sprinter only has 46,000 miles on it. If that doesn't work, then the Green Engine engine re-tune (what is that?) may be the next step. I really don't like the Sprinter dealership service department in my area and try avoiding them as much as possible. ANy advice would be greatly appreciated.

Click to expand...

See this thread:
https://sprinter-source.com/forum/showthread.php?t=30548

Weird, I have a 2007 Sprinter 3.0 V6 with the same codes. I ordered the rear sensor and received the white connector version with the central slot as per your last pic. However both my front and rear sensors have the same connector like the front black one, with the slot above pin one. I'll have to return this and order another.