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Change of AIR-pump


Jan Olsson

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I just replaced the AIR-pump on my STS (had codes P0416 and eventually P0410) A straight forward job which involves raising and jacking the vehicle, removing the lower splash-shield and remove the old pump (located with one screw and two nuts). The real challenge was to change the old inlet air hose from the old to the new design. The old design was mounted with a filter assembly that was mounted right behind and beneath the left headlight but the new pump had a new hose design. That particular hose was made to be situated just behind the headlamps and was quite tricky to get in place. Well now that job is done and the tires needed to be rotated so I took care of that too. The next few days I will keep my eyes on the SES-light but I think that the problem is solved. I noticed some new external oil leaks. The valve gaskets also leaks a bit and there seem to be a small leak from the lower half case. The engine is oily but there is never a drop on the parking lot. The new one however will be addressed the next oil change. The oil level switch and the oil cooler lines that seem to be leaking where the hoses are crimped to the pipes.

I just recovered somewhat from some illness, high fever followed by a cold made the sweat run down my nose and drip on the floor besides the temperature of 60F in the garage. Normally I would say that this isn't a hard job and doesn't require special tools. I'm grateful to the guys (and girls) at Cadillac who made such a easy worked car. This is relatively speaking of course since it is fully packed with just about everything. Somebody obviously gave this a real thought.

 

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You make it sound easy.  Congratulations on your success.

If you have an oil leak that only happens when the car is running, it's from a pressurized oil line.  I'm sure you thought of torquing the oil pan bolts.  You might also change the oil pressure switch; I once fixed a similar oil leak that way.

Sorry about your virus or bug.  My wife caught something like that at the airport in August and we've seen it around town lately.  It starts as a stomach bug and turns into a short flu-like illness with queasy stomach.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Thanks Jim! I just ordered new oil lines and a new oil level switch since it also is leaking.

Well the code P0410 came back again. The pump sure needed to be replaced because it sounded loud and screechy and smelled burned electrical motor quite bad. I checked the vacuum lines and the little check valve but they are in perfect order. I doubt that the two main air valves are both shot simultaneously so what remains for me to check is the fresh air tube from the pump and the operation of that little valve mounted on the rear cam cover. Hopefully I get some time for that tomorrow!

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The P0416 (Secondary Air Injection System Switching Valve B Circuit Open) may be a clue.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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DTC P0410

Circuit Description

The secondary air injection (AIR) pump used on this vehicle lower tail pipe emissions during start-up. The AIR system consists of the following items:

  • The AIR pump
  • The shut-off valves
  • The vacuum control solenoid valve
  • The system hoses/piping
  • The AIR relay, fuses, and related wiring

The powertrain control module (PCM) uses the AIR relay to control the AIR pump. The PCM also controls the AIR vacuum control solenoid valve that supplies vacuum to the AIR shut-off valves. With the AIR system inactive, the AIR shut-off valves prevent air flow in either direction. With the AIR system active, the PCM applies ground to the AIR relay, and the vacuum control solenoid valve. Fresh air flows from the pump, through the system hoses, past the shut-off valves, and into the exhaust stream. The air helps the catalyst quickly reach normal working temperature, thus lowering the tail pipe emissions on a start-up. The PCM tests the AIR system for the following conditions:

  • AIR system, overall system including both banks, and results in DTC P0410
  • AIR system bank 1 (DTC P1415)
  • AIR system bank 2 (DTC P1416)
  • AIR relay (DTC P0418)
  • AIR vacuum control solenoid (DTC P0412)

The PCM runs two tests to diagnose the AIR system: Passive, and Active. Both tests involve a response from the fuel control heated oxygen sensors (HO2S) bank 1 sensor 1 and HO2S bank 2 sensor 2. If both passive tests pass, the PCM takes no further action. If either part of the passive test fails, or is inconclusive, the PCM initiates the Active tests. If the PCM determines that the HO2S voltages did not respond as expected during the tests, DTC P0410. For further information concerning the AIR system and system tests, refer to Secondary Air Injection System Description .

Conditions for Running the DTC

Passive Tests

  • DTCs P0102, P0103 P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0151, P0152, P0153, P0154, P0155, P0157, P0158, P0161, P0200, P0300, P0335, P0336, P0351, P0352, P0353, P0354, P0355, P0356, P0357, P0358, P0506, P0507, P1133, P1134, P1138, or P1171 are not set.
  • The engine is running for more than 2 seconds.
  • The engine speed is more than 1000 RPM.
  • The throttle is steady.
  • The engine load is less than 80 percent .
  • The system voltage is more than 10.5 volts.
  • The mass air flow (MAF) is less than 35 g/s.
  • The air fuel ratio is more than 11.1:1
  • The engine coolant temperature (ECT) is between 5-110°C (41-230°F).
  • The intake air temperature (IAT) is between 5-72.5°C (41-162.5°F).
  • The power enrichment, or deceleration fuel cut-off (DFCO) not active.
  • The start up engine coolant temperature (ECT) is between 5-80°C (41-176°F).

Active Tests

  • The engine is running.
  • The engine speed is more than 1000 RPM.
  • The throttle is steady.
  • The engine load is less than 80 percent .
  • The system voltage is more than 10.5 volts.
  • The mass air flow (MAF) is less than 75 g/s.
  • The fuel system is in Closed Loop operation.
  • The evaporative emission (EVAP) purge is active.
  • The engine coolant temperature (ECT) is more than 68°C (154°F).
  • The short term fuel trim is between -3 and +3 percent.
  • The fuel trim is in cells 4, 5, or 6.

Conditions for Setting the DTC

Passive Tests

  • During the operation of the AIR pump, the HO2S voltage for both fuel control sensors is above 300 mV for 12 seconds, 350 mV for 9 seconds on a hot start.
  • When the AIR pump is turned OFF, the HO2S voltage for both fuel control sensors is below 600 mV for 25 seconds, 7 seconds on a hot start.
  • The condition is present for 3 occurrences.

Active Test

The HO2S voltage for both fuel control sensors is above 250 mV for 3 occurrences.

Action Taken When the DTC Sets

  • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
  • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

  • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
  • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
  • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
  • Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

  • An intermittent may be caused by any of the following conditions:
    • Low system air flow may cause this DTC to set.
    • Excessive exhaust system back-pressure
    • Moisture, water, or debris ingestion into the AIR pump.
    • Pinched, kinked, heat damaged, or deteriorated hoses or vacuum lines
    • Restrictions in the pump inlet, duct, or filter
  • If the condition is intermittent, refer to Intermittent Conditions .

 

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Hmm. I have checked all vacuum lines, the bypass valve and the solenoid. Everything works. That leaves the fresh air hoses from pump to the main valves and the valves itself. Since I had the P1416 code before (miswrote it before) I guess that the bank two valve likely is the culprit. I have to remove it and test it to be sure and because my wife has to work this weekend and some nights that will have to wait for now.

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You said that the old pump had been overheated.  The pump is supposed to run only for a few seconds after startup.  I believe that this is to help light off the CAT and start open-loop operation, after which the AIR pump is not needed.

A couple of things struck me as possible things to look at in the FSM write-up:

  • The P0410 code can be set by low air flow.
  • The P1416 code was set first, meaning that the Bank 2 Sensor 1 HO2S was calling the failure first.  When both HO2S sensors remained above 350 mv (0.35 Volts), both banks were failing so it set P0410.
  • The codes are set for low HO2S voltages, which mean lean measured A/F ratios - too much air, so the valves may not be turning off.

I posted the FSM writeup on P0410.  I can excerpt the troubleshooting chart that follows; I didn't upload it yesterday because its very long, and it refers to a Tech II often.  Also note that the HTML used in the DVD for the FSM pages isn't completely compatible as interpreted after cut-and-paste, so I have to strip the formatting and reformat the material using the Forum editor.  Since the troubleshooting chart is in the form of an HTML table, I will have to find another way, such as copying to Excel, then copying to a post - and I have not had good luck copying tables from Excel to Forum posts.

But I have found it a simple matter to read the FSM tables and produce a simple DIY procedure that does not require an FSM.

If you have a code reader handy that can read the freeze-frame data associated with the P0410, that may tell us valuable things.  Also, an OBD engine analyzer can do things like look at the HO2S waveforms and tell us the health of the CAT and HO2S' themselves.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Does the check engine light come on within 30 seconds of a cold start? Or does it come on when driving? During the 30 seconds of a cold start up, can you check that you have (if vacume controlled) vacume to the valves connected to the exhaust.  When you disconnect the air pump hose during the first 30 seconds of a cold start, you should hear the pump running, and feel air blowing out the tube from the pump.  On the other end of the tubes, you should feel hot exhaust air coming out.

worst thing is you can have a partially plugged up cat or restricted exhaust flow, and the air pump can not force air into the exhaust system - so the upstream O2 wavelength can not be detected by the downstream O2 sensor. So the p0410 is triggered. 

I am not sure how your car controls the exhaust valves, but it is sometimes an electrical solenoid that sends vacume to open the valve so the air pump sends fresh air inth the exhaust stream.  You might want to check that each valve gets good vacuum during the first 30 seconds of a cold start.

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21 hours ago, Cadillac Jim said:

You said that the old pump had been overheated.  The pump is supposed to run only for a few seconds after startup.  I believe that this is to help light off the CAT and start open-loop operation, after which the AIR pump is not needed.

A couple of things struck me as possible things to look at in the FSM write-up:

  • The P0410 code can be set by low air flow.
  • The P1416 code was set first, meaning that the Bank 2 Sensor 1 HO2S was calling the failure first.  When both HO2S sensors remained above 350 mv (0.35 Volts), both banks were failing so it set P0410.
  • The codes are set for low HO2S voltages, which mean lean measured A/F ratios - too much air, so the valves may not be turning off.

I posted the FSM writeup on P0410.  I can excerpt the troubleshooting chart that follows; I didn't upload it yesterday because its very long, and it refers to a Tech II often.  Also note that the HTML used in the DVD for the FSM pages isn't completely compatible as interpreted after cut-and-paste, so I have to strip the formatting and reformat the material using the Forum editor.  Since the troubleshooting chart is in the form of an HTML table, I will have to find another way, such as copying to Excel, then copying to a post - and I have not had good luck copying tables from Excel to Forum posts.

But I have found it a simple matter to read the FSM tables and produce a simple DIY procedure that does not require an FSM.

If you have a code reader handy that can read the freeze-frame data associated with the P0410, that may tell us valuable things.  Also, an OBD engine analyzer can do things like look at the HO2S waveforms and tell us the health of the CAT and HO2S' themselves.

I thought the pump was shot due to old age and many miles but it sems likely that an open valve would cause it to fry. I have got the FSM so that info won't be needed but thanks anyway! I had the cylinder one bank O2-sensor replaced a while ago. The others are still original. I don't think that the work done on the sensor is related because it took months after that until I got the codes. Just in case I checked the fresh air-lines but they seem to be in order. However I tried to suck on the control vacuum tube to the bank 2 valve to see if I could get a vacuum on that valve but that didn't work. Since there is only a small vacuum chamber it indicates that the valve is defect. I sure hope that it is not a restricted cat. My stupid Jaguar has got two clogged ones...

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20 hours ago, winterset said:

Does the check engine light come on within 30 seconds of a cold start? Or does it come on when driving? During the 30 seconds of a cold start up, can you check that you have (if vacume controlled) vacume to the valves connected to the exhaust.  When you disconnect the air pump hose during the first 30 seconds of a cold start, you should hear the pump running, and feel air blowing out the tube from the pump.  On the other end of the tubes, you should feel hot exhaust air coming out.

worst thing is you can have a partially plugged up cat or restricted exhaust flow, and the air pump can not force air into the exhaust system - so the upstream O2 wavelength can not be detected by the downstream O2 sensor. So the p0410 is triggered. 

I am not sure how your car controls the exhaust valves, but it is sometimes an electrical solenoid that sends vacume to open the valve so the air pump sends fresh air inth the exhaust stream.  You might want to check that each valve gets good vacuum during the first 30 seconds of a cold start.

It comes on after a bit of driving. That is I believe when the car has heated up enough for the system to make some self tests. The vacuum system curcuit is fully functional. However I did try to see if I could create a vaccum by sucking on the hose connected to that valve and that didn't work. I'm quite convinced that the valve is the problem but I will have to remove it and check further.

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On September 8, 2016 at 1:55 PM, Jan Olsson said:

It comes on after a bit of driving. That is I believe when the car has heated up enough for the system to make some self tests. The vacuum system curcuit is fully functional. However I did try to see if I could create a vaccum by sucking on the hose connected to that valve and that didn't work. I'm quite convinced that the valve is the problem but I will have to remove it and check further.

The self test for the secondary air injection system is only performed during it's operational stage which is around the first minute after a cold start.  Again, not sure of the particulars of your system, but could it be your car has a sensor that is telling obd2 that the valve is stuck in an open state? One thing for certain is that under normal conditions, this apparatus is idle and completely unused after that minute.  The easiest way to check is after a drive, disconnect the line coming from the valves, and make sure there are no hot exhaust gases flowing out in the direction towards the air pump.

if one or both valves are broken or melted, a early stage restricted exhaust can be a cause. Btw, you can get away with only one side working, and it will not set a code and it will still perform its function as far as 02 waveform detections.

i once filled in my melted valve with cement on one side to stop the hot exhaust gases from coming out, and the other side performed the job solo for years. - this was a chevy though.

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3 hours ago, winterset said:

The self test for the secondary air injection system is only performed during it's operational stage which is around the first minute after a cold start.  Again, not sure of the particulars of your system, but could it be your car has a sensor that is telling obd2 that the valve is stuck in an open state? One thing for certain is that under normal conditions, this apparatus is idle and completely unused after that minute.  The easiest way to check is after a drive, disconnect the line coming from the valves, and make sure there are no hot exhaust gases flowing out in the direction towards the air pump.

if one or both valves are broken or melted, a early stage restricted exhaust can be a cause. Btw, you can get away with only one side working, and it will not set a code and it will still perform its function as far as 02 waveform detections.

i once filled in my melted valve with cement on one side to stop the hot exhaust gases from coming out, and the other side performed the job solo for years. - this was a chevy though.

I'll remember that Logan once said that the code usually sets after 5-10 minutes of driving or something like that. Before I changed the pump the old one was loud enough that I could hear it inside the car while driving and I'm quite positive that after about 5-10 minutes the pump came on and suddenly the SES light whent on. I cleared the codes just to see if I was able to see some pattern when it set and it always set the second cold start after the code was reset and after 5-10 minutes of driving. However I changed the valve today (because the old one couldn't contain vacuum). I found a used one for about 60$ from a car with only 30 k on it. Time will tell if it was the cause. I cleared the codes and performed one drive. I haope that the SES won't light up next time I drive.

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I changed the faulty valve yesterday and after three cold starts there still isn't a SES-light. It seems that the valve was what set the code. The car seems to run smother and it even may have got a bit higher MPG. But it is way to soon to verify that. After a couple of weeks driving to and from work I'll see if that is a fact or just my imagination. Next thing on the to-do list is new oil lines, oil level sensor and wiper blades ;)

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Yes!  Often-neglected things are the oil cooler lines for both the engine (STS/ETC/DTS, not SLS/ESC/Deville) and transmission oil cooler lines.  The heat exchanger tanks in the radiator tanks are things to watch, too.

It needs an oil level sensor?  I didn't know that those gave trouble.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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There is a PCM-controlled secondary AIR solenoid-controlled vacuum valve that takes vacuum from the throttle body and applies it to the two AIR shutoff valves.  I don't see a sensor for the valves.  The PCM will have the voltages on the valve solenoid coil but the only way it could tell whether the valves are working is through the HO2S waveforms, through analysis.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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21 hours ago, Cadillac Jim said:

Yes!  Often-neglected things are the oil cooler lines for both the engine (STS/ETC/DTS, not SLS/ESC/Deville) and transmission oil cooler lines.  The heat exchanger tanks in the radiator tanks are things to watch, too.

It needs an oil level sensor?  I didn't know that those gave trouble.

The oil cooler lines for the engine oil cooler are leaking a bit. I'll look carefully at the transmission lines to while I'm at it! Well the sensor is fine but to see what dimension of O-ring I need I have to remove it so I thought I buy a new complete unit to save some time when the other parts arrive. I would hate to let the r&r wait just because I didn't find the right size and quality of o-ring in time. Thats what happened when I replaced o-rings on the oil cooler lines a couple of years ago. That's not where they are leaking by the way ;)

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15 hours ago, winterset said:

Congrats. Was the valve vacume controled, or electromechanical? If electric, how many wires were in the plug? I am curious if it had a way to detect it's position.

Thanks! It is vacuum controlled by a pilot vacuum valve that activates both the main valves at the same time. The PCM checks if they operate as they are supposed to do by estimating what oxygen level the O2-sensors should see when the AIR-pump is running. If the expected value doesn't match then the system does a series of self checks and tries to determine on what cylinder bank the problem lies. I had a P1416 code once but after that only P0410. What gave me the clue was the initial P1416 code.

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