Trouble Code P040B - Ex. Gas Temp Implausible signal
02-04-2023, 07:30 PM
#11
AudiWorld Super User
Thanks Wes....I did remove the intake tube and EGR pipe and cleaned the temp sensor - it was pretty dirty. I also discovered a very slight leak where the EGR pipe joins up to the intake tube, so I fixed that as well. My fingers are crossed that all is good. I did start her up and watched some live data and the sensor was reading temps. Also checked the coolant level - exactly where it should be, so at least all of those gaskets and seals I replaced are holding. I really do love this vehicle, and treat it with kid gloves, no hard acceleration, easy driving during warm up, nice long cruises...it's such a nice ride. I hope it understands my well-wishes and good intentions....and reciprocates :-)
So long as you enjoy your car, that's all that really matters IMHO, but please don't think you need to 'baby' it..3.0 TDI, both gen 1 and gen 2 engines, they are both runners. Just shorten up the oil change intervals, keep all the fluids/lubricants fresh, and find a good fuel additive to control water and boost cetane, anti-gel properties are a plus during winter too. 
Diesels like to be driven.
02-09-2023, 07:46 AM
#12
AudiWorld Member
Thread Starter
Hello 10Q7TDI_Prestige....well, the stupid CEL popped on during my drive up to Michigan, but no drivability issues at all for the entire 1,800 mile trip. I will try and check continuity of the sensor wires. Also would like to measure the resistance of the sensor itself, but I don't have a method of getting to the terminals inside the plug, maybe I'll get a male connector with wires - plug it in...and check it that way.
05-20-2023, 04:43 PM
#13
AudiWorld Super User
Hello 10Q7TDI_Prestige....well, the stupid CEL popped on during my drive up to Michigan, but no drivability issues at all for the entire 1,800 mile trip. I will try and check continuity of the sensor wires. Also would like to measure the resistance of the sensor itself, but I don't have a method of getting to the terminals inside the plug, maybe I'll get a male connector with wires - plug it in...and check it that way.
No CEL yet on the '10, but it is popping same trouble codes again on the pre-DPF temp sensor, and mentions the temp control valve as well, so curious. The TSB also mentioned quality control issues with the replacement EGR Coolers internal diaphragm, etc.
05-21-2023, 06:02 AM
#14
AudiWorld Member
Thread Starter
Hello 10Q7TDI_Prestige....shame-on-me....but still "playing this out". Life continues to throw some curve ***** our way. For over 35 years I worked in automotive, which is a fast paced, chaotic, and high-stress environment. A few years ago I left that "hot mess" and went into general manufacturing, what a change of pace...loved it, but now had to commute about a hundred miles a day. This long daily drive really kept the emissions system happy. But out of the blue, my previous employer asked me to return, which I did after some negotiation. Now my daily drive is only about 15 miles total - which is not good for the DPF regeneration cycle, sometimes I will extend my drive just to facilitate a good regen. Now that I'm back in the "fray" am working lots of hours, just no ambition left to dig into this issue yet. Still get the "implausible signal" code but have not observed any physical problems yet.
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-Wes- (05-21-2023)
05-21-2023, 08:37 PM
#15
AudiWorld Super User
Thanks for the update, and hope the job environment works out better this time. Stress is a silent killer.
Hey, Liqui Moly and others also make an additive to support DPF regens on TDIs not getting the longer drive times, and that just goes right into the fuel tank. You can always manipulate the RPMS higher by dropping into manual shift and drop couple gears to stay above 2000 so it'll build heat to support a regen cycle. Worst comes to worse you can kick off a manual regen too, but it's probably unlikely you'll need that.
You can also easily view in VCDS the status of DPF's soot/ash loading, pressure, last regen cycle, etc., etc. ad-nauseum. It's located under engine control module right around monitoring block 100, give or take a few. That's also, IIRC, where the adaptations relating to regeneration are for the DPF (engine control module).
Hey, Liqui Moly and others also make an additive to support DPF regens on TDIs not getting the longer drive times, and that just goes right into the fuel tank. You can always manipulate the RPMS higher by dropping into manual shift and drop couple gears to stay above 2000 so it'll build heat to support a regen cycle. Worst comes to worse you can kick off a manual regen too, but it's probably unlikely you'll need that.
You can also easily view in VCDS the status of DPF's soot/ash loading, pressure, last regen cycle, etc., etc. ad-nauseum. It's located under engine control module right around monitoring block 100, give or take a few. That's also, IIRC, where the adaptations relating to regeneration are for the DPF (engine control module).
11-13-2023, 02:26 PM
#16
AudiWorld Member
2014 3.0 TDI: Well after replacing the gaskets and seals for the Oil Cooler, EGR Cooler, and the Coolant Diverter Valve, and related items...all seemed well. An initial test drive of only about 5 miles and no issues. The next day I make my 40 mile drive to work and back with no issues. But the following day, just as the motor was getting up to operating temps, the CEL popped on. I had my laptop and VAG cable with me so I checked and got Code P040B...exhaust temp sensor bank 1 implausible signal. I was hoping it was related to all the work I just did, so I cleared the code and and continued driving - it did not return. Then at lunch time I was going out for a bite and within a mile the CEL popped on again, same issue. Now I'm a little worried. I checked the electrical connector it looked fine, unplugged - replugged, cleared the code and it did not come on again during the drive. Then on the way home it popped on again. I hooked up Vag-Com and logged some data for the exhaust temps of bank 1 and 2. Bank 1 hovered around 190C while bank 2 hovered around 245C. I don't know what the operating parameter are supposed to be, but based on the difference between banks 1 and 2....I assume the sensor may be bad. I will do some more testing tomorrow on this.
Any feedback on this is welcome....thanks gang!
Any feedback on this is welcome....thanks gang!
I had a leak in my oil cooler, had it replaced and also just got the same error code popup a few days later along with P245B
02-15-2024, 08:37 AM
#17
AudiWorld Member
Thread Starter
Hello MWAARNA,,,sorry for the late reply. I've just been living with it - so far no obvious issues after thousands of miles. I'm not even sure where exhaust temp sensor bank 1 is located. I am getting tired of seeing the CEL though, so sooner or later I need to address this.
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