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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29588
Experience:  GM Grand Master Technician 2007. 14 years experience.
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2012 duramax,diesel. california def issues....display says:"

Customer Question

2012 duramax,diesel. california def issues....display says:" diesel exaust fluid quality poor"
im thinking wafer filter on bottom of pump,or modulator on top of tank.or nozzle in the exaust system
i need help.over warrenty,and there is a recall on modulator but im over on miles
Submitted: 1 year ago.
Category: Chevy
Expert:  Roy replied 1 year ago.

good evening my name is ***** ***** I will assist

do you have a refractometer to check the def fluid??? It needs to be around 35%

I would also remove the def injector and make sure the passage is not clogged.

Roy

Customer: replied 1 year ago.
fluid is brand new.i can check passage tommorrow..where is the modulator thats on recall?
Customer: replied 1 year ago.
i pulled the pump and cleaned the wafer filter,tank was spotless for debries,christalizing
Expert:  Roy replied 1 year ago.

check the passage.

the modulator is in the pump.

what is the code that was showing??

Roy

Customer: replied 1 year ago.
i dont have a code reader,should i get one? not sure if it will help
Expert:  Roy replied 1 year ago.

you can have it read by a parts store for free.

the code will help in what direction to go. it will generate a flow chart to follow for the failure.

Roy

Customer: replied 1 year ago.
chevy has a recall on modulator.if its part of the pump i am willing to replace pump with will replace modulator,what do you think?
Expert:  Roy replied 1 year ago.

I think we need to start with the code to be sure we address the issue correctly. the modulator may be the issue but it is a guess right now. I hate to guess as it is wrong most of the time

Roy

Customer: replied 1 year ago.
ok will get code reader tommorrow
Expert:  Roy replied 1 year ago.

thanks, ***** ***** can work through the issue properly

Roy

Customer: replied 1 year ago.
codes:p20ee p2bad nox11, nox12,p203d,p205c.p21ab.p21b0.v029d.v010e.p22ao
def tank currently empty and light is illumited on dashalter clearing codes the following codes remained . p2bad/p20ee/p203d/p205c
Expert:  Roy replied 1 year ago.

have you added def yet?? that alone will set multiple codes

Roy

Customer: replied 1 year ago.
i havent so add def, clear codes and see what we got?
Expert:  Roy replied 1 year ago.

thats correct

Roy

Customer: replied 1 year ago.
new def added .same 4 codes remain... im am going to let idle for a few hours,,,by the way there is no pressure on output line from def pump to injector
Expert:  Roy replied 1 year ago.

ok

Customer: replied 1 year ago.
i ran for 2 hrs at idle
2 hrs at 2000 rpm
same four codes
mil status noX11 o ppm
noX12 0 ppm
Customer: replied 1 year ago.
where do we go from here?????
Expert:  Roy replied 1 year ago.

sorry, I am having computer problems here getting any info. I am opening this up to the other guys. someone will be along shortly.

do not respond or rate or it will stay locked to me

Roy

Expert:  GM Tech (Cam) replied 1 year ago.

Hi there, I am Cam. Can I get your name please?
wOuld a phone call help you out?

Expert:  GM Tech (Cam) replied 1 year ago.

Also can you post your mileage and Vin? There might be a special policy that covers these.

Customer: replied 1 year ago.
Rod dement..its over special warrenty @120000 miles
Expert:  GM Tech (Cam) replied 1 year ago.

Rod, ok. Too bad on that.

So looking at the codes, the level sensor code P203D is likely just that, a level sensor issue, the P205C does not come up.

As for the others, There are 2 possible options that I see, first the NOX sensor 2, second is the DOC (exhaust).

Most of these that I see are that NOX sensor 2. Are you able to drive it while watching the sensor reading?

Customer: replied 1 year ago.
No its down to the 4 mph limp mode
Expert:  GM Tech (Cam) replied 1 year ago.

Ok so still clearing codes again, those 4 still come back?
During the fluid test, what did the NOX 1 and Nox 2 PPM readings show?

Customer: replied 1 year ago.
Sensors showed nox 11 @0
[email protected]
This is after running 2 hrs at idle and 2 hrs @2000 rpm
Expert:  GM Tech (Cam) replied 1 year ago.

OK, NOX 1 should be 80-120 and 2 should be 70% less than this when running. This makes me think that either your scanner is showing you wrong or the sensors are bad.

Customer: replied 1 year ago.
I will try reading again....any certain rpm during test?
Expert:  GM Tech (Cam) replied 1 year ago.

Normally i get these while driving, so maybe 1500?

Customer: replied 1 year ago.
Ok..will try in a min
Expert:  GM Tech (Cam) replied 1 year ago.

ok

Customer: replied 1 year ago.
Nox 11 is 129
Nox 12 is 0
Customer: replied 1 year ago.
P205c code shows "redunctant tank temperature sensor circit low"
Expert:  GM Tech (Cam) replied 1 year ago.

Did NOX 2 show anything more than 0 at any time?

OK, right it did not show up as an individual code. Lets chase that. Below are the diagnosis for that code.
"

Install any components or connectors that have been removed or replaced during diagnosis. Perform any adjustment, programming, or setup procedures that are required when a component or module is removed or replaced. Clear the DTCs. Ignition Off, all vehicle systems Off, this may take up to 2 minutes.

Note:

The diesel exhaust fluid (DEF) and ambient air temperatures must be greater than −7°C (19°F) before proceeding with this procedure.

Exhaust Gas Temperature (EGT) sensor 2 must be less than 200°C (392°F) prior to running the Reductant System Leak Test.

Ignition On, command the Reductant System Leak Test On with a scan tool. Allow the pressure to build for 30 s. Observe the scan tool Reductant Pressure sensor parameter. The reading should be between 400–600 kPa (58–94 psi) and there should be no leaks in the system. Ignition Off, all vehicle systems Off, this may take up to 2 minutes. Engine idling for 30 s. Ignition Off, all vehicle systems Off, this may take up to 2 minutes. Ignition On. Perform the Reductant System Data Reset with a scan tool in order to clear the DEF lamp.

If the DEF lamp does not turn Off

A condition with the system still exists.

If the DEF lamp turns Off

Perform the Reductant System Malfunction Warning Test with a scan tool in order to clear the Service Emission System message, if displayed.

If the Service Emission System message does not turn Off

A condition with the system still exists.

If the Service Emission System message turns Off

All OK.

Customer: replied 1 year ago.
Not sure if my scan tool can do that test
Nox 12 is now reading 1017 ppm
Nox 11 is at 112
Customer: replied 1 year ago.
Nox 11 is now 134
Nox 12 is at 1946
Expert:  GM Tech (Cam) replied 1 year ago.

Wow, ok the sensor cannot tell the difference between NOX and DEF so it may be saturated. Did you check to see if the injector was leaking?

Customer: replied 1 year ago.
No
Customer: replied 1 year ago.
Pulled def injector,no leaks
Expert:  GM Tech (Cam) replied 1 year ago.

Ok so can you do a service regen on the Exhaust filter then to burn up any extra DEF in the system?

Customer: replied 1 year ago.
Tell me how...
Nox 11/12 read 0 with vechile running and injector not installed
Expert:  GM Tech (Cam) replied 1 year ago.

OK, Does your scanner allow you to so a service regeneration?

Customer: replied 1 year ago.
No....i reinstalled injector...
Nox 11 @0
Nox 12 @0
Expert:  GM Tech (Cam) replied 1 year ago.

Ok, we need to do that, But for now, do the other 2 codes set still?

Customer: replied 1 year ago.
Not sure if this is def psi on scanner
Dpf1. Dp (psi) reads .2 up to .6
Dpf1 int 234 degrees
Dpf1 out. 189 degrees
Customer: replied 1 year ago.
All 4 codes still remain
Expert:  GM Tech (Cam) replied 1 year ago.

No, not pressure but the levels. Here is the specific testing for the level sensor.

Inspect the wire harness on the B213 Reductant Level Sensor for damage.

If damage is found

Replace the B213 Reductant Level Sensor.

If no damage is found

Disconnect the harness connector at the B213 Reductant Level Sensor side of the B212 Reductant Sensor Module.

Note: The reductant tank level must be full to ensure accurate resistance readings.

Verify the resistance is between 9.6-10.2 kΩ between the ground circuit terminal 7 and the terminals listed below at the B213 Reductant Level Sensor wire harness.

Terminal 4 for level sensor 3

Terminal 5 for level sensor 2

Terminal 6 for level sensor 1

If not between 9.6-10.2 kΩ

Replace the B213 Reductant Level Sensor.

If between 9.6-10.2 kΩ

Replace the B212 Reductant Sensor Module.

Customer: replied 1 year ago.
Nox 11 now at 129
Nox 12 at 0This is frustrating
Customer: replied 1 year ago.
Now
11 at 164
12 at 2700
Expert:  GM Tech (Cam) replied 1 year ago.

Ok, if I may, my gut feeling is you have a bad NOX sensor 2.

Customer: replied 1 year ago.
K..im willing to try..which one is that
Expert:  GM Tech (Cam) replied 1 year ago.

The rear most one on the frame.

Customer: replied 1 year ago.
K...will order on and get back too you
Expert:  GM Tech (Cam) replied 1 year ago.

Ok, I hope as well it works. In the mean time, diagnose the level sensor issue to be sure that’s not also an issue.

Customer: replied 1 year ago.
Is that the issue eveone is having and the cause of the recall?
Expert:  GM Tech (Cam) replied 1 year ago.

Its not a recall but a special policy. Yes this is very similar to many others. Exactly the same I cannot say because I am not confident of the scanner your using.

Customer: replied 1 year ago.
Would a more expensive scanner let me do a regen?
Expert:  GM Tech (Cam) replied 1 year ago.

Yes, that I am 100% sure.

Customer: replied 1 year ago.
Get parts on thurs
Nox sensor was in middle of system,egt sensor was at end
Expert:  GM Tech (Cam) replied 1 year ago.

Yes but there are only 2 NOX sensors, one at turbo and one in the DOC.

Customer: replied 1 year ago.
I got one near muffler, last item in exaust was a exaust gas temp sensor,figured thats good
Expert:  GM Tech (Cam) replied 1 year ago.

Yes I agree. No codes for that sensor, so lets leave it be. Just the NOX sensor there.

Customer: replied 1 year ago.
i pulled the def pump and found major electric burn in the level sensor,im going to order a new pump as well at the same time
Expert:  GM Tech (Cam) replied 1 year ago.

Stand by with the NOX sensor then if you can. Now that we have identified some other major issue, Lets deal with that. OR get the NOX sensor but leave package sealed.

Customer: replied 1 year ago.
Will do
Expert:  GM Tech (Cam) replied 1 year ago.

Yup, that would do it.

Expert:  GM Tech (Cam) replied 1 year ago.

Any updates?

Customer: replied 1 year ago.
Yea..wrong part was ordered by dealer,have to wait till after christmas now
Expert:  GM Tech (Cam) replied 1 year ago.

ok

Customer: replied 1 year ago.
parts finally shipped..new resevior.nox sensor position one.nox sensor position 2
same four codes remain
truck was run for two hrs an 2000 rpm
Expert:  GM Tech (Cam) replied 1 year ago.

None of the previous relies show. Remind me the codes, parts and procedure you used to clear the codes.

Customer: replied 1 year ago.
p20cc
p203d
p205c
p2bad
Customer: replied 1 year ago.
parts
nox position one sensor
nox position 2 sensor
reservior level sensor in def tank(previos one was burned)
Expert:  GM Tech (Cam) replied 1 year ago.

Ok, what procedure did you use to clear those codes? Simply replacing parts does not do it. These are very particular. Did I post any documents to follow for clearing it?

Customer: replied 1 year ago.
just used code reader
allowed truck to ran at 2000 rpm for two hrs to hopefully regen
nox sensors read normal numbers now
Customer: replied 1 year ago.
no documents were posted
Expert:  GM Tech (Cam) replied 1 year ago.

Ok, this is where we run into troubles. WE need a FULL FUNCTIONED scanner first to command each reductant heater on, then to perform a fluid quality test, then to do a regen and finally to do a tamper reset. The first 3 most aftermarket scanner will do, the tamper reset is a gm only thing.

Its not as simple as resetting codes, the system requires these steps to re-enable the system.