Hi all, I've had some VAP headers installed on my Aston Martin DBS - she sounds amazing despite giving up the renowned throaty Aston growl. She has a stage 3 tune for the primary/secondary cat removals with the CEL cleared however, after restarting my car am receiving the "emission system service required" message that stays constant again with a P0141 and P0161 error (apparently to do with the O2 sensors on bank 1 and bank 2) - does anyone know how to repair this?

Separately did anyone feel a significant increase in power (probaby yes if you own a DB9) because I haven't found any change. Also, is there anyway to remap the throttle box so it can be more sensitive in non-sport mode?

 

Hi @DBS down under

These codes, P0141, 0161, are O2 sensor heater circuit errors. With headers, (on a number of other cars on which I've worked) heater circuit errors are pretty common because the O2 sensors are physically moved much further away from the engine. So the engine, which contributes to a lot of the O2 sensor temps the ECU is expecting to see are no longer there and the O2 sensor is only relying on its own internal heater which, typically, is not enough on cold start warmup.

That's the explanation, of what's happening, but how you fix it is the challenge. I could manipulate these in the tune. You said you have a stage 3 tune. If it were my car, I'd probably seek the tuner out (if you're not a canned tune) to see what they have to offer.

Hope this helps,

 

Thanks bwings, that does - I've emailed Velocity AP so hope that the tune can be modified and that's the only issue. It's going to be a pain for the mechanic to replace O2 sensor-related parts if it's a mechanical problem...

 

I've given you the wrong diagnosis in post #2. Too early in the morning and I wasn't concentrating yet.

Let me try again - These codes are both sensor 2 codes on both banks, and not sensor 1s. With sensor 2 codes, and CATless, the downstream sensors check for oxygen past the CATS. When they get too much unburned fuel they report failures. But same as above, these can be adjusted in the tune if there is no startup diagnostics built into the EMS, but these faults are for heater circuits, so possibly the check the downstream sensors are doing are tuned out already, just the heat circuits failing.

If you have a Velocity tune you're in good hands, and this is where you should go for answers.

 

A relatively low cost option if it’s not tune related would be to replace the o2 sensors and see if it solves the problem. If they haven’t been replaced in a while who knows maybe moving them around during the header install has contributed to their demise if they are older sensors.

 

If you have our ECU Tuning, you will need a specific file for our headers if you have added them, and not adjusted the tune. https://www.velocityap.com/ecu-file-upload/ - just upload your file here along with all the modifications and your order number for the parts you are adding.

 

Thanks Stuart, I've done so and have been emailing Chris who suggested that I need to do a few drive cycles before the errors disappear. Do you know how many km/miles this would constitute (just so I know when I should follow up with VAP and/or my mechanic).

 

Chris will know. And also just to be clear - I'm just stating that you need a specific file for the headers, and for the O2 locations, not to fix those codes. If the HEGO circuits aren't working properly there's a wiring continuity issue somewhere, or an issue with the sensors themselves.

 

Hi Stuart/Bwings, thanks for your guidance - I brought the car back to my mechanic who plugged back in the downstream sensors and tiewrapped them to the frame, CELs no longer appearing in the dash cluster.

Side note: for those contemplating the VAP headers/tune, I would highly recommend. For a catless set-up, my DBS seems to rev more freely and feels more torquey with a slight improvement in fuel consumption although you'll find it hard to resist aggressive driving. The noise is addictive; head-turning is an understatement. One thing to note, is you'll need to drive it a couple of hundred km to notice both the improvement in sound and performance (presumably the headers baking in affects the sound and the ECU tune needs to learn the new parameters). Catless set up also makes your garage and cabin smell like a petrol station. Am very happy, but my neighbours not so much!!