DTC Help Needed

[VetPet]

I'm getting a P1416 "Secondary Air Injection (AIR) System Bank 2" trouble code and am looking for the diagnostic chart. If anyone could provide one it would be greatly appreciated. I have a 2001 C5, LS1.

Thanks,

[eboggs_jkvl]

Usually the check valves. When we see the code we say replace them both.


http://www.ls2.com/boggs/torques/enginetorques.htm


The codes are there.

[VetPet]

Thanks kindly eboggs. I've had quite a few issues with secondary air injection system. Could you tell me where the check valves are located in the system?

[joecar]

On metal tubes bolted to the exhaust manifolds, one per bank.

[VetPet]

I can see the check valve that's on the driver's side but I can't see the one on the passenger side. Is it hidden somewhere near the back of the engine near the firewall and can you access it without too much trouble? My car is a 2001 C5 with the LS1. I need to get at it so I can perform some of the diagnostics.

Thanks

[joecar]

On your car, passenger side AIR check valve is located to the rear of driver side (bank 1) head and has a tube crossing to passenger side (bank 2) exhaust manifold (towards rear of manifold)...

From the passenger side, look toward rear of exhaust manifold, you should see a tube bolted to the manifold (2 bolts)... follow this tube as it goes behind the engine and to the rear of driver side head.

It sure is hidden...

[VetPet]

Thanks Joecar. I just had a repair done recently to fix a vacuum hose at the rear of the engine that was giving me a P0410 code (secondary air injection system) also. Do you think the check valve could have been damaged because the vacuum line controlling the air pump was melted? Could exhaust have gone back towards the check valve & damaged it because of this?

[joecar]

The check valve is designed to block [hot] exhaust backflowing...

The hot side if the check valve is a steel tube, the cold side is a rubber hose...

If a check valve had failed, it would allow hot exhaust to backflow into the rubber hose which would have damaged the hose and any surrounding plastic components.

The AIR plumbing usually develops internal condensation after engine cool down, and when combined with exhaust gases when engine is running, the check valves get corroded internally, they weaken and let exhaust gas thru... so over time the check valves will fail just be virtue of their environment.

[joecar]

From the GM service manual:

Secondary Air Injection (AIR) System Description

The secondary air injection (AIR) system helps reduce exhaust emissions. The system forces fresh filtered air into the exhaust stream in order to accelerate the catalyst operation.
The system includes the following components:

1. The AIR pump --The AIR pump supplies filtered air through the secondary air injection system into the exhaust stream. The control module provides ground for the pump relay, then the battery voltage is applied to the pump. The filter is the only serviceable part of the pump.

2. The AIR vacuum control solenoid --The AIR vacuum control solenoid controls the AIR Shut OFF Valve. When the secondary air injection system is enabled, the control module provides a ground to the solenoid. Enabling the solenoid allows the engine vacuum to be applied to the AIR shut off valve.

3. The AIR shut off valve--The AIR shut off valve is vacuum operated. When the secondary air injection system is enabled, vacuum is applied to the valve. The vacuum opens the valve, and allows air from the AIR Pump to flow to the check valves.

4. The check valves--The check valves prevent back flow of the exhaust gases into the secondary air injection system. An inoperative AIR pump that had shown indications of exhaust gases in the outlet port would indicate a check valve failure.

5. The plumbing --The plumbing carries the air from the pump to the exhaust stream. The plumbing includes the hoses, the pipes, and the clamps. You can test the plumbing for leaks using a soapy water solution. With the AIR pump running, the bubbles with form if a leak exists.

Results of Incorrect Operation

If no air flow enters the exhaust stream, the start-up emission levels will rise. The control module can detect a system flow problem using the pre-catalyst HO2S and the short term fuel trim. If a system flow problem exists, the HO2S voltage will not indicate an expected lean condition. The short term fuel trim will not increase, and a DTC will set.
If incorrect voltage is present on the vacuum control solenoid or on the pump relay control circuits, the device will not operate. The control module will detect this condition, and a DTC will set.
If a secondary air injection fault is detected. the following DTCs can set:

P0410--A system flow problem has been detected.
P0412--A vacuum control solenoid control circuit problem has been detected.
P0418--A pump relay control circuit problem has been detected.
P1415--A Bank 1 flow problem has been detected.
P1416--A Bank 2 flow problem has been detected.

[VetPet]

Thanks Joecar, This problem is probably related to the P0410 code I had a while ago. The vacuum line at the back of the intake going to the air pump valve was melted so I probably had a weak check valve on bank 2 to begin with. Once I fixed the line I had vacuum to operate the air pump valve which allowed air into the injection system again. It sounds like the check valve may be stuck closed and not allowing air into bank 2 this time. It's probably a good idea for me to change both check valves.