When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Been getting intermittent cold start P2258 codes:
P2258 Secondary Air Injection System Control A Circuit High
First things first, replaced the secondary air injection system relay.
The first cold start after the relay change and code clear, I got no codes. On the second cold start after the first, I got a new code:
1065 - Secondary air valve 1 has a short circuit to positive.
I did a thorough visual check around the electrical connectors and vacuum hoses, I couldn't see any splits or disconnects anywhere. The car is quite low mileage, 18700 miles. Has remap from MSL in Birmingham UK, Wavetrac diff and secondary cat delete.
I was looking for the pump itself for a visual check.. but I couldn't see it anywhere! Anybody know where it is?
Also, to help diagnosis - I am using iCarSoft. It would be useful for some way to manually trigger the secondary air injection system, instead of waiting overnight for the car to get cold. Is there any way to do this?
Being that your scan tool is limited do you have a vacuum pump or way to apply it? maybe even a gauge? Here's a quick run through of what to check. Have the engine running go straight to the valves. Remove the big fat line coming from the pump while you do this. Apply vacuum to each one at a time. Do you hear the valve opening? Should allow exhaust to escape from the large hole and sound like a deep low volume chug sound. That rules out the valves and passages in the cylinder head. You can also vacuum check the solenoid. With engine running does the vacuum line going into the solenoid have good vacuum? From here it gets tricky. You really need the system to actuate to test. Does the solenoid pass vacuum to the valves while actuated? When the pump is running it should sound like a small vacuum cleaner. The big fat line that feeds both valves - does it appear to be putting out a good amount of air? If all of those checks seem to be pretty legit i'd go after the oxygen sensors. Most common failure point is the pump - typically blows a fuse. However on a car of your low mileage i doubt it. You're likely looking for rodent damage on either the big fat line from the pump to feed the valves or a vacuum line. The solenoid and valves are uncommon and even more so clogged cylinder head ports. Oxygen sensors should be replaced every 50k or so, considering your mileage I doubt they're bad yet.
Thank you for that reply! I'll keep it all in mind when I start troubleshooting further.
Before I started it today, I had a good nose around the engine bay, I kid you not I must be blind but I can't see the pump from the engine bay. I can see where the fat hose goes near the passenger side front bumper area somewhere, but I can't see the pump. I can't see me having any sight of it unless I remove the undertray from below and look up into the bumper, or remove the bumper entirely. There is no sight of it through the front bumper views are blocked.
So, I started it today to see if error is reproduced (codes were cleared last cold start).
First I started monitoring on my diagnostic tool 'commanded secondary air injection status'. I wanted to compare if I could hear the pump compared to the air injection command from the car.
Right after starting it, I saw the status go to ON for about 1 second, then went to off again. No EML, no lights or any pump noises. I guess the car didn't want the system on this time, even though it was a cold start.
Then did another crank and this time status didn't change from OFF at all.
How on earth am I supposed to diagnose this thing if it doesn't even consistently get command from the ECU??
Just tried it again. This time the EML came on after about 3 seconds after crank, with the first code P2258. I did hear the pump this time, it came on several seconds after the EML was triggered, was on for a couple of seconds then went off again.
I wonder if it is some kind of weak electrical connection to the whole system..
Tried some more starts, I saw DTC's being stored but without EML being on. It's possible the EML is only lit after a certain amount of DTC's are stored maybe.
Anyway, I want to be as sure as possible before I start replacing things. I really can't hear the pump running to be honest and it's looking more and more likely. I can only remember hearing it once a few starts ago, although it was not very obvious and it only seemed on for a few seconds.
I took out the switchover valve today and inspected it, looks fine nothing out of the ordinary.
P2258 Secondary Air Injection System Control A Circuit High 1065 - Secondary air valve 1 has a short circuit to positive.
I may start with the switchover valve first as it's a lot easier to get to, and then if no luck will start investigating the pump.
Replaced the secondary air valve 1, switch over valve, whatever you want to call it today.
After replacement, the DTC still returned on a cold start. After having a further snoop around the engine bay.. there's another valve that was hidden under the cover. So I replaced this one with the old one, and fingers crossed next cold start I don't get any errors.
Decided to test the pump first before blindly removing and replacing it.
I shorted the relay connections first in the fuse box, and the pump turned on. Surely this would rule out a pump issue. Relay itself is new, so the system must be capable of getting power. Fuses will be OK too.
I then started it cold, and sure enough the code came straight back.
1065 - Secondary air valve 1 has a short circuit to positive.
Now while I was nosing around in the engine bay, maybe about 1 or 2 minutes AFTER starting the car, I heard the pump switch on and I'm sure I heard the switchover valves click, can't tell if it was both but definitely heard at least one. The pump started at moderate speed then soon after went quite loud for about 10 seconds, and then stopped. But it sounded all normal and healthy. I didn't hear any hissing or air leaks that were obvious.
I'm gobsmacked now, it must be some kind of control input somewhere but no idea what it could be. Also this check seems to happen before the pump itself turns on, straight after starting cold, so the check must be done on engine start.
Another thing that is baffling me is that the code states 'secondary air valve'. The secondary air valves are the big metal vacuum valve I believe, but this is passive/vacuum controlled so how could this report a DTC? I don't see any electrical connectors on them either.
I do have the secondary cats removed, I wonder if the problem had started after this? Is there anything around that area that could trigger this problem?
Did a little more digging today. Only a small portion of the harness is visible, as it goes under the intakes and then around the back of the engine somewhere and I think it comes out the engine ECU area.
I traced the harness as much as I could and honestly couldn't find anything odd anywhere.
I did some more troubleshooting, this time I disconnected both air switchover valves, to see how the DTC's would react and see at least which one was causing the short circuit error.
This was interesting, after cold starting with both disconnected, I got a new error code for each:
Secondary valve 1 has an electrical fault!
Secondary valve 2 has an electrical fault!
Which leads me to believe both harnesses are at least live as it's detecting disconnection of the valves. It's also worth noting, the pump did not come on at all for this duration of a few minutes with both valves disconnected.
I then connected the left hand side one (I don't know which valve is 1 or 2 yet relating to the error codes). As soon as I connected, the pump came on and did it's thing for about 5 seconds. It's obvious that connecting the valve let the system activate.
The Secondary valve 1 has an electrical fault! also changed from current to historic, so now we know that it's definitely the left hand side valve that is number 1.
I also got another code for the other side:
I can't remember exactly but the code was, but it was something to do with secondary air flow not being sufficient in bank 2. Expected, as valve 2 was still disconnected, yet the system had started already.
So from all of this.. I feel the system is fully functional, but some small control is interfering with it somewhere. No idea what this could be. We know the harnesses are working as system is reacting to changes to it, and know the pumps functional. Relay is new. Valve 1 is also new.
There is one thing I want to try next, which was an observation from my last test. When I was waiting for the system to activate after cold starting, the system actually came on as soon as I started fiddling with the valve 1 electrical connector. I thought this was a coincidence, but maybe it wasn't I wonder if it is a bad connection on this side. I will try this tomorrow.
I got the multimeter out today to measure and monitor voltages. I measured in both switchover valve harnesses. Consistent behaviour in both, ~8.4v at ignition on on each side, and goes to 0v a minute or two at ignition off. I didn't bother measuring the voltage at engine on, or when the system is active. I'm confident the power levels and the system itself is OK, especially considering the plethora of codes I got when I disconnected the valves in the earlier test.
Once again, a couple of minutes after cold start, I heard the pump kick in. This time I was monitoring on the iCarSoft the pump and valve status. From what I remember, the pump turned on first, then one valve was activated for a few seconds, then pump went faster, then second valve, then pump went really fast, and then after a few seconds everything turned off. I can hear the exhaust note change also when it activates.
I would hope this is normal operation, maybe someone could compare with their C63 if the cold start sequence is similar? It would be useful to know if we have to wait a couple of mins after engine start to hear the pump, or if it starts straight away on other cars. Every information document I read seems to stay pump stays on for a minute or two, mine only stays on for several seconds.
I haven't vacuum tested the metal valves, I do have a vacuum tester kit I wonder if this is worth doing or if it could cause my symptoms. Only 19k though on my car, but who knows.
The one thing that is completely consistent, is that the DTC get's raised on a cold start, pretty much straight away after engine start. I have never seen it appear again on subsequent starts, even if I turn it off after a short start and turn it on again.
01-28-2022, 05:59 AM
