Cadillac Owners Forum banner

1 - 20 of 49 Posts

·
Registered
2006 Cadillac DTS
Joined
·
62 Posts
Discussion Starter #1 (Edited)
So I have been trying to trace down why I have a P0411 code for insufficient flow because i need my car inspected. Apparently I have a leak in the gasket that is in between the exhaust manifold and the Catalytic Converter, and another leak on the flex pipe that connects to the EGR valve. I was thinking of taking a wire brush and cleaning up the area real good and applying furnace cement, and unsure the fix for the EGR flex pipe, but I can clearly hear a leak there also. Any recommendations of what I should do, I have used furnace cement for other car exhaust leaks, works like a charm. EGR system clears as ready, so is this a contributing factor to the P0411 code? Also note that i replaced the check valve, and the air pump supplies plenty of air. attaching a video to show the issues.
 

·
Registered
2006 Cadillac DTS
Joined
·
62 Posts
Discussion Starter #2
Re: P0300 Cadillac DTS Exhaust Leak before Catalytic Converter

I accidentally posted a P0300 code in my title for this thread, it is actually a P0411.
 

·
Registered
2006 Cadillac DTS
Joined
·
62 Posts
Discussion Starter #3
Re: P0300 Cadillac DTS Exhaust Leak before Catalytic Converter

Bump. ALso note, do you guys think running exhaust wrap will be the fix for the EGR flex pipe? Wrap with furnace cement/ exhaust wrap, and then apply a adjustable clamp. My idea, any others? Also I fixed the leak at the gasket connecting to the catalytic converter using furnace cement.
 

·
Registered
2006 Cadillac DTS
Joined
·
62 Posts
Discussion Starter #5
Wow, you're asking about duct tape and furnace glue on a Caddy forum. Why not fix it right, it's a Caddy...
Lets see, less then 10 dollar fix v. fixes that will be over 1000 dollars. Temp fixes will serve my purpose atm. Nobody said anything about duct tape, though it has its purpose... unless your giving me the money to make the correct fix (You should, its a caddy) otherwise its getting a temp fix until I have the money for such. Back to my original question, Can a leak at the EGR be a contributing factor to a P0411 code?
 

·
Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
Joined
·
70,295 Posts

·
Registered
2006 Cadillac DTS
Joined
·
62 Posts
Discussion Starter #7
P 0411 has nothing to do with EGR. AIR and EGR are very different systems.

https://www.cadillacforums.com/forums/cadillac-dts-forum-2006-through-2012/807426-acronyms.html

Unfortunately the P 0411 definition itself doesn't give you much to go on.

Always post the definitions for any codes found.

http://www.cadillacfaq.com/faq/answers/dtccode.html
I was thinking the exhaust escaping from the flex pipe at the EGR would possibly contribute to the p0411 insufficient flow being its before the catalytic converter. Stopped these two leaks and still same code came back after resetting the codes. Any other ideas? Replaced check valve, repaired leaks, maybe i need to check for leaks on the front manifold and down. If all else you think throwing a new pump will make any difference?
 

·
2006 DTS perf
2006 DTS Performance Lux III
Joined
·
1,223 Posts
I was thinking the exhaust escaping from the flex pipe at the EGR would possibly contribute to the p0411 insufficient flow being its before the catalytic converter. Stopped these two leaks and still same code came back after resetting the codes. Any other ideas? Replaced check valve, repaired leaks, maybe i need to check for leaks on the front manifold and down. If all else you think throwing a new pump will make any difference?
Try wrapping that egr pipe and seal the exhaust leak. If the code clears I would go to rockauto and get the egr pipe they're not that much and it would be a permanent fix. Another possible cause could be an 02 sensor on the way out but still working enough not to throw a code. I hope you resolve it with the quick fixes. I like the shop vac on the exhaust never thought of that its a good way to look for leaks.
 

·
Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
Joined
·
70,295 Posts
Remember that there will always be one or two cylinders open to atmosphere in a V-8 engine = all the valves are never closed at the same time, so a hissy/airy noise (with shop vac) could simply be air flowing through an open cylinder. Each cylinder has valve overlap where the intake and exhaust valves are partially open at the same time.

You can ALWAYS move some air through a V-8 exhaust-cylinder-intake-air filter tract forwards or backwards. A tad less so in a 6, maybe not always in a 4 - depends on valve opening height and timing events.

Here's a sample cam timing/overlap diagram.

E = Exhaust
I = Intake
O = Opens
C = Closes
TDC = Top Dead Center
BDC = Bottom Dead Center
 

Attachments

·
Registered
2006 Cadillac DTS
Joined
·
62 Posts
Discussion Starter #10
Try wrapping that egr pipe and seal the exhaust leak. If the code clears I would go to rockauto and get the egr pipe they're not that much and it would be a permanent fix. Another possible cause could be an 02 sensor on the way out but still working enough not to throw a code. I hope you resolve it with the quick fixes. I like the shop vac on the exhaust never thought of that its a good way to look for leaks.
If it is the o2 sensor, then is it the upstream or the downstream that checks for the lean condition to make sure the secondary air is working correctly?
 

·
Registered
Joined
·
757 Posts
DTC Descriptor DTC P0411 Secondary Air Injection (AIR) System Incorrect Air Flow Detected
Diagnostic Fault Information
Circuit Short to Ground Open/High Resistance Short to Voltage
AIR Pump Control Voltage Supply P0411 P0411 P2444
AIR Pump Ground P0411
AIR Pump Relay Coil Ignition Supply P0102, P0412, P0418 P0418 P0690
AIR Pump Coil Relay Control P0418 P0418 P0411, P0418, P0690, P2431
AIR Pump Relay Switch B+ Supply P0411 P0411
AIR Solenoid Control Voltage Supply P0411 P0411 P2440
AIR Solenoid Ground P0411
AIR Solenoid Relay Coil Ignition Supply P0412 P0411, P0412 P0690
AIR Solenoid Relay coil Control P0412 P0412 P0411, P0412, P0690
AIR Solenoid Relay Switch B+ Supply P0411 P0411
Circuit/System Description The secondary air injection (AIR) system aids in the reduction of hydrocarbon emissions during a cold start. The system forces fresh filtered air into the exhaust stream in order to accelerate the catalyst operation. The secondary AIR injection pump provides filtered air on demand to the AIR solenoid check valve assembly. The AIR solenoid valve assembly controls the flow of air from the AIR pump to the exhaust manifold. The AIR pump relay supplies the current needed to operate the AIR pump. The AIR solenoid valve assembly has an integral check valve, pressure sensor, and solenoid valve. The pressure sensor monitors the air flow pressure from the AIR pump. The engine control module (ECM) supplies the internal pressure sensor with a 5-volt reference, a low reference, and a signal circuit. The signal circuit provides the control module with a voltage relative to internal air pressure changes.
The AIR diagnostic uses 3 phases to test the AIR system:

  • DTCs P0411 and P2430 run during Phase 1
  • DTCs P2430 and P2440 run during Phase 2
  • DTC P2444 runs during Phase 3
During phase 1, both the AIR pump and the solenoid valve are activated. Normal secondary air function occurs. Expected system pressure is 8–15 kPa above BARO.
During phase 2, only the AIR pump is activated. The solenoid valve is closed. Pressure sensor performance and solenoid valve deactivation are tested. Expected system pressure is 15–22 kPa above BARO.
During phase 3, neither the AIR pump nor the solenoid valve is activated. AIR pump deactivation is tested. Expected system pressure equals BARO.
In all 3 phases, testing is accomplished by comparing the measured pressure against the expected pressure. The control module can detect faults in the AIR pump, AIR solenoid, pressure sensor, and the exhaust check valve. The pressure sensor can also detect leaks and restrictions in the secondary AIR system plumbing.
 

·
Registered
2006 Cadillac DTS
Joined
·
62 Posts
Discussion Starter #12
also forgot to note, I did take it to a local garage, and they checked the check valve and air pump through commands without issue. The guy at the shop recommended replacing the check valve which I did, to no success against the code.
 

·
Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
Joined
·
70,295 Posts
"if it is the O2 sensor..........."

AIR operates briefly during cold starts or when coolant temp is below a set value in order to quickly light off the cat. At those times O2 sensors are not active. At loop change coolant temp - about 160 degrees depending on ambient temperature - the emissions sensors activate and the AIR system is OFF.

The O2 sensors, either pre-or post- cat, do not affect AIR operation (or vice versa) because the sensors are inactive when AIR operates.
 

·
Registered
2006 Cadillac DTS
Joined
·
62 Posts
Discussion Starter #15
"if it is the O2 sensor..........."

AIR operates briefly during cold starts or when coolant temp is below a set value in order to quickly light off the cat. At those times O2 sensors are not active. At loop change coolant temp - about 160 degrees depending on ambient temperature - the emissions sensors activate and the AIR system is OFF.

The O2 sensors, either pre-or post- cat, do not affect AIR operation (or vice versa) because the sensors are inactive when AIR operates.
Ok so its purely based upon pressure? 8–15 kPa above BARO according to danogs post.
 

·
Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
Joined
·
70,295 Posts
Pressure and monitored electrical functions within the AIR system.

EGR doesn't operate until emissions loop change, then it meters exhaust gases into the incoming fuel/air mixture - depending on throttle opening/power demand - to slightly cool the combustion temperature thus lowering nitrous oxides emissions. A leaking EGR system could screw up fuel mixture ratios.
 

·
Registered
2006 Cadillac DTS
Joined
·
62 Posts
Discussion Starter #17 (Edited)
I have the online haynes manual for the vehicle and it said the relay was located right behind the coolant reservoir. So I had a look and I found this, two different connectors wires completely cut off and no signs where they go. No clue if this is the relay or what they control. Maybe someone knows. IMG_20190318_170925.jpg
IMG_20190318_170906.jpg
 

Attachments

·
Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
Joined
·
70,295 Posts
On my 2002 STS the AIR relay is gray/blue, clipped to that same strut tower as yours. The correct wiring schematic is in the paper GM/Helm service manuals (eBay) or in a subscription to the GM/Cadillac online service manuals at www.alldatadiy.com. Even the online Haynes is far too generic for our cars.

Some Devilles had two AIR pumps, not sure about the later "DTS" - which is not a Deville.

See the blue connector up right of the fuse box? That's the relay and its electrical connector, hung on a clip on the strut tower.
 

Attachments

·
Registered
2006 Cadillac DTS
Joined
·
62 Posts
Discussion Starter #19
On my 2002 STS the AIR relay is gray/blue, clipped to that same strut tower as yours. The correct wiring schematic is in the paper GM/Helm service manuals (eBay) or in a subscription to the GM/Cadillac online service manuals at www.alldatadiy.com. Even the online Haynes is far too generic for our cars.

Some Devilles had two AIR pumps, not sure about the later "DTS" - which is not a Deville.
ya the DTS only has the one air pump on the driver side. Was looking for wiring diagrams but not seeing any online that are specific. Can you tell on yours where those wires trace to? maybe its similar enough to give me direction where to look. Annoying the previous owners just cut these wires... Looks like maybe I will have to stop by caddy dealer and see if I can get them to print off for the secondary air system :-/. Or spend looks like 200 bucks for wiring diagrams.
 

·
Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
Joined
·
70,295 Posts
Wiring physical placement - maybe tomorrow. I'm riding shotgun in the Explorer on the way to a group dinner. 27 miles to go ........

Do the Alldata trick - your car is quite different from mine. As well as wiring color ID markings.
 
1 - 20 of 49 Posts
Top