Forum Chat #48 – Emissions error, crying wolf? Aston Martin emissions error help

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Welcome to BamfordRose and another forum chat. This week it’s the return of the perennial emissions service required error message on the dashboard.

Together with the staple comment of ‘Which oil should I use?’ The emissions error on the Aston Martin cars at least forms a staple part of any Facebook or forum. That’s because the error pops up quite often.

I’ve covered this subject before with error codes and symptoms and faults, which are serious, which need to be checked out and don’t drive the car. And we’ve covered codes which aren’t serious which are just emissions related like lambda sensors or secondary air EGR, faults on those sorts of circuits, which if appear don’t really cause any consequence to driving the car. Why I’m mentioning it again now is because I’ve seen a worrying trend on online forums probably because the system is crying wolf so often of advice to owners that post a cry for help saying what should I do. And the advice is to take it for an Italian tune up. Take it for a spirited drive. It’ll sort itself out.

So, whether it’s V8 or V12, for emissions systems such as the fuel pump or fuel tank leak detection system, this is going to identify if the fuel tank cap was left off for instance or there was a leak in the system, any one of those the error light will come on. Maybe the canister purge circuit is malfunctioned, so this is the gas that vents off from the tank that runs through the charcoal canister and back into the inlet manifold so that the car is consuming its own vapors, its own gases. Perhaps there’s a leak in that system. Something with secondary air injection, so this is the pump that runs immediately after cold start just to inject some fresh air into the exhaust system so it lights the catalyst off quicker, so it starts converting gas quicker. Maybe it’s the EGR system, this is Exhaust Gas Recirculation that’s going to take spent gas from the exhaust manifold and probably to about a dilution of five percent and feed it back into the inlet manifold in an attempt to reduce nitrous oxide emissions. Or it could be the lambda sensor. It’s got a slow response. I mean this is the most common reason for the emissions error light on the dashboard to pop up.

So, any one of those errors, it’s okay to run the car and not attend to the fault code or the problem. But if it was misfire and this will be a code starting p3 and then whatever the cylinder, so 08 for cylinder 8p308, or if it was a catalyst efficiency problem p420 or p430, or if it was anything to do with the electronic throttle pedal or the electronic throttle blade, throttle body, those problems should definitely not be ignored because continuing to use the car could put the engine at risk or you could risk a breakdown because the car goes into a limp home or a shutdown mode.

So, it’s all about plugging into the car with an OBD scan tool, read the code yourself, very easy to do, the diagnostic port is in the footwell directly above the pedals, it’s simple to plug an OBD scan tool into that port, read the codes and very quickly get the exact code that the system is troubled with. And then reset it if it’s inconsequential or if it’s one of the more serious ones then get to a garage pretty quick to have a little bit of diagnostic work done. But because the system cries wolf so often and by that, I mean it will trigger one of those non-critical emissions system problems, often you see on forums that the advice is to just give it an Italian tune up.

Now if you did that and it was for a misfire, then you’re continuing to run the engine in that misfiring state, especially if it was a V12, that’s a bad thing to do because we all know about cat ingestion. So, I’ve selected a couple of OBD scan tools and at the cheap end you can see this one that I picture here. This will be effective enough just to plug into the port, get the engine management system codes, understand what the problem is and then reset it or visit the garage. And now this more intelligent scan tool that I picture here, this will actually be able to read other modules on the car instead of the engine controller. So, you’ll be able to read and reset some airbag faults, some brake module or somebody module codes. Now not just for the Aston, but this more intelligent bit of kit that I feature here will work on lots of cars and you can download software files for each car to the device and then go and use it in the car.

So, for your 100 or so quid, what you’re doing here is buying a bit of kit that you can use for the rest of your driving career on many many cars. I was at an MOT station the other day and this is just your honest back street garage, it doesn’t specialize in anything. And a sign on the wall in their office said, a read of fault codes is a standard charge of 50 pounds. So, the outlay here of 100 quid or so for the more intelligent bit kit for the rest of your driving career, it’s certainly going to make this kit a good investment to make.

And also, if you do get a problem which even though you can’t fix it at home, at least when you go to a garage, you are more armed with information about what the problem is with your car and more in control of understanding what the fix required is. As I’ve said before in a previous video, if it’s the more simpler cheaper bit of kit, it’s only going to read the engine module, no other modules and on a V12, it’s not going to read the secondary ECU because to communicate with the second ECU it has to go through the body control module and the cheaper bit of kit won’t do that whereas the more expensive bit kit I feature here will do that.

When you read the fault codes what you’re looking for is a code which triggered the freeze frame. And on the more intelligent bit of kit, it will specifically list the fault code which triggered the freeze frame, so this is the actual cause, this is the actual problem. Now, if it was a serious fault like faults with the electronic throttle pedal or the throttle body motor itself, any fault with those triggers a limp home mode and that will be like a p2106 forced shutdown. Now those codes are the symptoms or the effect of the actual root cause of the problem.

I often get a phone call saying, Hey! I’ve plugged into my car. I’ve got p2106. What’s wrong? Well, p2106 is just telling you that it’s shut down. It’s not actually telling you what the real fault is. The real fault will be something else and on that more intelligent bit of kit, it will say to you in the fault code. Read the code which triggered the freeze frame.

Arm yourself with a good OBD scan tool and if you get an error message on your dashboard, plug in, understand what it is yourself and then make a decision from that point whether to drive the car further or whether to seek help pretty quick. And although the system does cry wolf, just treat every error message on the dashboard as a point of caution and without understanding what that fault code is definitely do not take it on an Italian tune up or just keep running and running and hope it will go away. Because by doing that, if it’s one of the more severe reasons, it could result in quite a catastrophic fix being required.

Hope you like that forum chat. As ever, it really helps us if you can like, comment and subscribe and we’ll see you on the next one.

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