Air Injection Pump schematic
 

Does anyone have a schematic for the Air Injection Pump (the emissions control pump on US spec cars)? I have the 2004 Electrical Guide from the sticky, but that document does not show any of the AIR system. Seems to be the only deficiency in that manual.

Thanks,
-Michael

Hi Michael,

That's strange! The 2005 Electrical Guide doesn't show the AIR system either, but the 2006 version does - see Figure 3.9 in the manual at this link:

http://www.jagrepair.com/images/Elec...al%20Guide.pdf


I'm also attaching the section on the AIR system from the Powertrain section of the Workshop Manual, which explains the system operation, identifies the components, and mentions that the air pump relay is located on the air pump mounting bracket.

What is prompting you to deal with the AIR system?

Cheers,

Don

Thank you Don! This 2006 electrical guide seems to have quite a bit more info than the '04 guide. I never noticed the 04 was missing the TPMS system as well.

My AIR system makes an "popping" (or sharp clicking) sound whenever I leave the car outside in the winter (below 40F). Just one of those minor annoying issues that are on the to-do list to fix. I had it in to the dealer under warrant, but they claimed they couldn't replicate it and that it was likely the air switching valve. From the operating description, the air diverter valve operates once at the beginning and once at the end of the air pump run cycle. I know a couple other people on the forum have had the same issue.

Anytime the temp is over 40F the pump runs sliently on startup. I'm guessing it's the pump itself. Maybe the motor bearings are worn and the end play causes the noise when cold.

Here's a video I captured of the noise a few years back.

That is really strange! I've never had to mess with the secondary air injection systems on any of our Jaguars. You might be able to isolate that sound with a little careful probing with a mechanic's stethoscope, as long as you keep the probe away from any belts, fans or other moving parts.

Yes--it is very strange. I have not heard an electric motor make a noise like this, but I've had the hood open and it's not coming from the diverter valve that sits in front of the belt drive. It definitely is loudest at the bumper where the pump motor is. The only other thing down there is the relay, which is not making that noise.

It's possible there may be some kind of relief valve internal to the pump that is acting up in the cold. If I could get a used air pump I might swap them and take mine apart to see what's inside.

The difficult part is that it can only be replicated at low ambients. I'd have to remove the wheel liner and park it out in the cold. Any time it's in my garage it never makes the noise (of course).