Thread: C1A20-64 (68) Pressure increases too slow when filling reservoir

C1A20-64 (68) Pressure increases too
slow when filling reservoir - Algorithm
based failure - signal plausibility failure

Hi All

Looking for some feedback

D4 AMK Air Compressor last replaced with genuine about 6 years and 70K km ago

Last week after getting 2 new tyres and driving home I got the above code

I think the timing was co-incidental, I can't see what the tyre shop could have done to cause issues.

I did also replace battery 2 days before this.

To prevent further issues I got it to normal ride height and disabled by putting into build mode with Gap IID.

I understand this can be issues other than compressor such as a leak or bunged up.

In the week since disabling the corners haven't dropped, I think rulling out air bag leak, or hoses and valve outlets to the corners.

I did get this error last year at 2 different times doing water crossings, which I chalked down to a potential wiring issue.

Last year I did open up and there was no breakdown of the beads or powder / gum build up. I didn't have seal kits but the seals looked healthy enough so replaced beads and put back on. Checked again yesterday and beads are good and no powder / gumming.

Did some more testing last night
- using gap iid and service test valves the back and front raised quickly using what's in reservoir, which I think means valve blocks and lines are ok
- enabled compressor, put it down to access mode, then into off road mode, monitoring gap iid, with valves closed, it took over 7 minutes for gallery pressure to rise from about 165 to 240 PSI which I assume is too slow, can anyone confirm. It cut out with fault code again
- I sprayed sudsy water around centre valve block, compressor and reservoir and while it was dark no obvious leaks bubbling
- I disabled compressor while reservoir was open and filling while gallery was at high pressures, over maybe 10 minutes pressure dropped by maybe 6 or 7 psi

To rule out other issues before spending $s on a new compressor what else should I do
- replace seals
- could the front or rear valve be leakeding i.e. just at connection back to central valve block, if corners are not dropping ?
- anything else ?
- pressure sensor replacement ?

I replaced filter and dryer and o-rings, but ended up replacing compressor and all good. I suspect there was a hairline crack or something and compressor is bdes up getting wet