I used the onboard air compressor to inflate all 4 tires from 15psi to 34/37psi. The first two tires worked fine but when I started the third tire the display showed “E4” and stopped working. I had to turn it off and back on several times as well as let it rest and turn on again. It took ages to inflate the last two tires. I need to be able to rely on the compressor so any ideas what the error is and how to resolve? I couldn’t find anything in the install instructions or online.

 

First guess is what I feared about that unit, duty cycle. It can't run the full 1/2 hour or so (ok a little less if not to 48-50 psi) it would need to reinflate all four tires non-stop. I bet it shut down to prevent damage from overheating.

 

What do you expect when you only pay a grand for a compressor? You get a toy.

Yeah, exactly what KevM says. Those little guys get thermal overload pretty quickly and take a while to cool off enough to finish the job.

You can:

1) use it to put “just enough” air in the tires to get back to a proper compressor, say 22-25 pounds each

2) fill two and wait 15 minutes before filling other two

3) see if a good shop can replace with a Viair P400, which will do the job all in one sitting, in my experience. The Viair comes with alligator clips for battery posts, but you could hardwire one in wherever the factory one is wired, I just don’t know what that looks like.

 

That’s what I thought. Very disappointing. My old Defender has an ARB compressor fitted in the engine bay and could inflate 6-8 tires in one go with no issues. Does anyone have access to the user manual and any reference to an E4 error?

 

E4 error is because it can't pick up a pressure in to tyre. Sometimes the can be that the hose connecting to the compressor isn't connected correctly. I pulled the cover off fixed up the cover mount around the outlet so it could connect properly and it's been good ever since.


Quite comfortably pumps up all 4 tyres, just takes a while
The only peev I have is that when pumping up Schrader (on my bike) valves, if it over inflates and has to drop a bit of pressure, because the Schrader valve locks out, the compressor then looses it's pressure reading and E4 error comes up again. So I have to take the hose off, plug it onto a tyre with standard valve (this clears E4) then reconnect again to the Schrader valve to continue inflating