Code P0410 - Did the SAS Delete but Code Persists

ryanmcgrim · Post by **ryanmcgrim** » 20 May 2016, 13:54

I've got a 96 Volvo 850 NA that has been throwing a p0410 code. It's now time to get it inspected and I am having a heck of a time getting this CEL light off.

I saw Robert's video about doing a SAS delete by purchasing a diode and soldering it into the ECU.

I purchased a 1N4003-E3/54 STANDARD, 1A, 200V, DO-204AL Diode and soldered it between pin 32 and 37 with the gray line towards pin 37.

I put the ecu back in, cleared the code, and unplugged the air pump at the power wire (the connection with 2 main wires going to it).

Started the car, and the CEL immediately came back on. Cleared it again with the car running, and it stayed off until shutting the car off and turning it back on again. It appears to come back on immediately after startup every time.

I rechecked a bunch of forums to make sure I had done the procedure right, which I did (except for a few random older posts that actually said to connect to 38 instead of 37, but I could not verify this so I thought nothing of it.

I determined that I must have burned out the diode while soldering (i'm not the best at it).

I bought a 10 pack of Diodes (VISHAY GENERAL SEMICONDUCTOR 1N4003-E3/54 STANDARD DIODE, 1A, 200V, DO-204AL (10 pieces)) and tried soldering in another one, more quickly using less heat, and did a pretty good job. Put the ECU back in and cleared codes, p0410 still comes back everytime after startup.

Can someone point me in the right direction as far as order of operations for diagnosing this issue? I thought this diode deleted the SAS system, so no other pieces could be causing this issue? Not sure what else to try, and I've only got until next week to get this to pass inspection. Please Help!!!

ryanmcgrim · Post by **ryanmcgrim** » 23 May 2016, 09:47

I've been trying to do a lot of reading on this subject while I wait for someone who knows more than me to chime in.

It would appear that doing the diode dix to the ECU, will allow the pump to be removed, but I would still need to keep the Solenoid, vacuum lines and relay(which is attached to the pump on my 96 model).

Therefore it is possible that one of these other SAS components is faulty and continuing to cause the p0410 code to come up?

Does anyone know how to test the components that need to stay after an SAS delete?

Thanks so much.

Post by **erikv11** » 23 May 2016, 11:10

Good to know Robert has now added SAS delete to his collection of videos. I've never watched that one so I don't know what's in there, but yes there is confusion out there about this trick so I always direct people to the same thread, written by the people who figured out and where it is explained simply and completely: http://volvospeed.com/vs_forum/topic/14 ... with-pics/

You can't test the diode on the ECU, but using a voltmeter you can check the one you took off to see if it was cooked. If it wasn't then you know the problem is indeed elsewhere.

As explained in the original thread, you can get rid of all the vacuum lines too, long with the pump and the SAS valve. If it is still throwing a code, and you are not cooking diodes, then the first place to look is definitely the solenoid. I don't know how to test it though, I would just swap in a spare ... Relays are easy to test, again I can't recite a procedure but google is your friend.

Post by **sleddriver** » 26 May 2016, 00:27

When I did this delete last year, I seem to recall there was a mistake in the original post. Either a pin miscount OR counting from the wrong end of a connector. Can't quite remember. However it did work for me fortunately as yet another blower motor had died and I wasn't looking forward to spending ANY on another one!

What a PITA system.......

Post by **erikv11** » 26 May 2016, 00:57

The original post from VS is/was/always has been clean. There was a pin identity mistake the first time someone at MVS made a post about it, pointed out later in the thread. And there was a video up at VS with a pin counting mistake in it. But that post I linked up there is clean, 100% correct: the proper pins are named and counted off correctly.

ryanmcgrim · Post by **ryanmcgrim** » 26 May 2016, 11:43

Thanks for all the help guys. You are all correct, the first post on the SAS (including pictures) identified the wrong pin (b38 it think instead of 37), but I saw that and went through everything before I soldered the diode in. Looks like I'll be testing the solenoid and the relay (which in my year, 96, was physically attached to the pump connector instead of the up where the other relays are, under the hood fuses.

I'll try to get a procedure to test these two things and update here when I know what's going on.

Thanks again!

Post by **MrAl** » 26 May 2016, 19:26

Hello there,

Sorry to hear about your problem, i know it can be a pain to deal with this.
I had a problem with the 410 code too when i first got my car over a year ago. I went the route of replacing the air pump though so never did the diode trick.

Having over 40 years experience in electronics in the design and testing of various types of systems, i can help a little i think.
FIrst, the 1N4000 series diodes are very common and in the standard leaded package (like you have 10 of) are very hardy devices. Even with some overheating it is doubtful that you blew out the diode because of that, as long as the leads are not cut too short, say about 1/2 inch or longer like 1 inch each. Soldering should be done in about 3 seconds or less, but making sure the solder joint is done right because if the diode does not make good contact with the connection point it wont work right.

A property of all diodes is that they are polarized. Unlike resistors diodes have a polarity that must be observed when installing in any circuit. The end with the 'band' is the cathode, and the other end is the anode. The diode can only conduct when the anode is made more positive than the cathode, although any installation drawing should have this already figured out and drawn appropriately.
What this means though is that there is a possibility of installing the diode backwards. If that's the case, then you would simply turn it around and solder it that way instead.

So my first question is, did you connect the diode observing the correct polarity, which would probably come from any drawing or schematic or photograph you were going by?

My second question assumes that before you connected the diode and cleared the 410 code it took some time (minutes, hours) before the CEL would come back on to indicate the 410 error code, and that after you installed the diode it came on almost immediately after the car was started after first clearing the code again. Thus i assume that the failure behavior was different before you installed the diode than after you installed the diode, so the diode did change the time it took for the CEL to come back on.

If this is the case, then my next question is, what happens if you take out the diode and put back the air pump? Does the original behavior come back again, or does the CEL come right back on again like it did after the diode install?
I ask this to possibly find out if something else got damaged during the diode soldering operation. If the original behavior does not return, then maybe something else got damaged on the computer board or even something else like a loose connector or wire that broke off.

So that's two questions:
1. Is the diode installed with the correct polarity?
2. Does the same behavior return after removing the diode (and probably putting back the air pump)?

Post by **erikv11** » 26 May 2016, 20:14

If you do remove the diode, be sure to check it, see if it is cooked. Heck check the ones you haven't installed, make sure they are all good.

Gerd · Post by **Gerd** » 07 Nov 2020, 16:30

Hey guys. I am trying to do the diode 32-37 jump and I have a small issue. On my Bosch ecu, I can find the "30" on the outside of the unit but no numbers inside. And it seems to me like it is set up opposite to the unit RobertDIY modified in his video. Attaching images.
Not a big deal as I won't be putting solder on it until I know for sure what is what but if someone has a link to an image that is similar to mine with the 32 and 37 pins marked out, that would be great.

I am assuming it is the outside wires with the 32 being 3 in from the gap and the 37 5 after that but you know what assume gets you ...

Thanks

: I tapped the 30 with a Sharpie.; IMG_0005.jpg (95.16 KiB) Viewed 1880 times

: this is obviously from the inside but I cannot find reference numbers; IMG_0006.jpg (199.28 KiB) Viewed 1880 times

Richard99 · Post by **Richard99** » 07 Nov 2020, 17:20

Should just replace pump + check valve