Just want to give a shout out to all the people who rove these forums offering their wisdom and knowledge on Volvo's.
So my air pump was filled with water and rusted. I removed it and put in a new air pump from a used car (check the air pump and it in fact turns on and runs)
the light went away (YAY) and now a new code p0410 pops up, and in the morning I hear the air valve open and i hear chugging in the tubing but the air pump stays off.
code p0412 "Secondary Air Injection System Switching Valve A Circuit Malfunction"
so I don;t know what to do from here.
The solenoid works (tested and the valve opens each morning) the Relay works (tested it) only thing I can think is ECU signal continuity and I have no idea which pin and which wire need to be tested for conitnuity.
Can the waise and helpful members of MVS offer any insight into this issue? it would be greatly appreciated, need to pass smog so I can register the car and not be left with no ride.
1996 850 - po412 code after p0410 code fixed
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Klausc
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The Secondary Air Injection System (AIR) Switching Valve is the computer controlled valve that controls the air injection into the exhaust system of the engine (this valve may be integral to the AIR pump). This code deals with a problem on the circuit of the SOLENOID, not the operation of the AIR pump itself.
The AIR injection system reduces hydrocarbon emissions (HC) Carbon Monoxide (CO) and oxides of Nitrogen (NOx) by injecting fresh air into the exhaust ports of a cold engine or catalytic converter of a warm engine. This helps convert hydrocarbons into water vapor (H20) and Carbon Monoxide to Carbon Dioxide (CO2).
Generally the electric air pump is the most common type, although there may be belt driven air pumps with an electric clutch. The electric air pump is controlled by the PCM (Powertrain control module) which grounds the AIR pump relay control circuit and provides voltage to the AIR pump and solenoid valve (which may control a vacuum operated shut off valve or directly control air flow). There is a check-valve in the fresh air supply tube which prevents exhaust gasses from backing up into the AIR pump. The PCM monitors the driver that activates the AIR pump for faults. When the PCM commands the AIR pump relay on, the voltage of the control circuit would naturally be pulled close to zero. When the relay is commanded off, the control circuit would have battery voltage present. If the PCM sees a voltage that isn't what is expected, P0412 will set.
The AIR injection system reduces hydrocarbon emissions (HC) Carbon Monoxide (CO) and oxides of Nitrogen (NOx) by injecting fresh air into the exhaust ports of a cold engine or catalytic converter of a warm engine. This helps convert hydrocarbons into water vapor (H20) and Carbon Monoxide to Carbon Dioxide (CO2).
Generally the electric air pump is the most common type, although there may be belt driven air pumps with an electric clutch. The electric air pump is controlled by the PCM (Powertrain control module) which grounds the AIR pump relay control circuit and provides voltage to the AIR pump and solenoid valve (which may control a vacuum operated shut off valve or directly control air flow). There is a check-valve in the fresh air supply tube which prevents exhaust gasses from backing up into the AIR pump. The PCM monitors the driver that activates the AIR pump for faults. When the PCM commands the AIR pump relay on, the voltage of the control circuit would naturally be pulled close to zero. When the relay is commanded off, the control circuit would have battery voltage present. If the PCM sees a voltage that isn't what is expected, P0412 will set.
Klaus
If I had a larger garage, I could have more Volvos.
If I had a larger garage, I could have more Volvos.
Yes I can use google too, its the first thing that pops up when you type in "p0412".
I am just wondering what PIN from the wiring harness of the ECU to which wire end needs to be check for continuity. If thats all good, then how do I check that the ECU is ok?
My dilemma is that the relay works, the solenoid works, the air pump works, the air valve works and there are NO holes or tears in any of the hoses or any of the vacuum lines yet it still throws a code and I cant pass smog. Now the air pump does not turn on at all when hooked up to the system and put in its place BUT if I pull it out and hook up a battery to the connectors it turns on and blows air.
I am just wondering what PIN from the wiring harness of the ECU to which wire end needs to be check for continuity. If thats all good, then how do I check that the ECU is ok?
My dilemma is that the relay works, the solenoid works, the air pump works, the air valve works and there are NO holes or tears in any of the hoses or any of the vacuum lines yet it still throws a code and I cant pass smog. Now the air pump does not turn on at all when hooked up to the system and put in its place BUT if I pull it out and hook up a battery to the connectors it turns on and blows air.
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jblackburn
- MVS Moderator
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First of all, is fuse #8 and its socket OK?
Pin B38 from the ECU will connect to pin 85 of the SAS relay. That is what signals the pump to turn on.
Pin 30 should connect to the chassis ground along with the starter.
Pin 86 should be getting power from the car's main relay (any time ignition key is on).
Pin 87 receives input from front O2 sensor (if you don't have other O2 sensor codes, don't bother with this one).
Hope this helps.
Pin B38 from the ECU will connect to pin 85 of the SAS relay. That is what signals the pump to turn on.
Pin 30 should connect to the chassis ground along with the starter.
Pin 86 should be getting power from the car's main relay (any time ignition key is on).
Pin 87 receives input from front O2 sensor (if you don't have other O2 sensor codes, don't bother with this one).
Hope this helps.
'98 S70 T5
2016 Chevy Cruze Premier
A learning experience is one of those things that says, "You know that thing you just did? Don't do that."
mercuic: Long live the tractor motor!
2016 Chevy Cruze Premier
A learning experience is one of those things that says, "You know that thing you just did? Don't do that."
mercuic: Long live the tractor motor!
Yes the fuse was good (not sure how to check socket) but your information was very specific and very helpful jblackburn.
All the pins and wires still were showing positive for continuity so I went to a friend who was parting out a Volvo very similar to mine and grabbed his ECU.
I popped it in my car and voila! the car turns on and the air pump kicks on for about 90 seconds then turns off. Functions like normal.
I tested the solenoid, the air pump, the relay separately to see if they function and they worked.
I checked continuity on the wire from the air pump to the relay, from the relay to the ECU PINS from the solenoid to where the solenoid wires went. I tested all wires in every combination possible.
I checked all hoses and vacuum lines for cracks.
Still check engine, turned out to be the ECU.
what someone very knowledgable (works at a dealer) about volvos told me about swapping the ECU:
putting an ECU from a 1997 850 GLT into 1996 850 basemodel shouldn't cause any issues especially if your emissions code is the same. Emissions code is the 7th number on the VIN. This is specifically what I was told.
in my case:
if you look at your BOSCH ECU all the numbers with a barcode on-top matched up and out of the two strings of numbers under the BOSCH logo just the top one matched. and it plugs in and functions fine no lights on the dash any my car runs great!
I don't know much and I don't have much help to offer or knowledge but I hope someone finds this post/thread helpful.
All the pins and wires still were showing positive for continuity so I went to a friend who was parting out a Volvo very similar to mine and grabbed his ECU.
I popped it in my car and voila! the car turns on and the air pump kicks on for about 90 seconds then turns off. Functions like normal.
I tested the solenoid, the air pump, the relay separately to see if they function and they worked.
I checked continuity on the wire from the air pump to the relay, from the relay to the ECU PINS from the solenoid to where the solenoid wires went. I tested all wires in every combination possible.
I checked all hoses and vacuum lines for cracks.
Still check engine, turned out to be the ECU.
what someone very knowledgable (works at a dealer) about volvos told me about swapping the ECU:
putting an ECU from a 1997 850 GLT into 1996 850 basemodel shouldn't cause any issues especially if your emissions code is the same. Emissions code is the 7th number on the VIN. This is specifically what I was told.
in my case:
if you look at your BOSCH ECU all the numbers with a barcode on-top matched up and out of the two strings of numbers under the BOSCH logo just the top one matched. and it plugs in and functions fine no lights on the dash any my car runs great!
I don't know much and I don't have much help to offer or knowledge but I hope someone finds this post/thread helpful.
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