Have P1470 code on 1997 A8 ? EVAP LDP Leak Detection Pump electrical malfunction. Any idea were the pump is? What is the cause? What is the fix?

 

17878
P1470
EVAP Emission Contr.LDP Circ Electrical Malfunction

This code tells me that the LDP pump has an electrical failure which almost never happens on any audi. The pump is located in the right rear wheel well behind the plastic wheel guard. If you take off the fender liner you should see the LDP pump with a bunch of hoses connected to it. Check to see if there are and problems with the wiring and try to follow the wiring towards the front of the car looking for any damage. If you recently had a blown tire it could have damaged the wiring/lines by the right front which is pretty common. Other than that it could be just a faulty pump, but i must warn you, everyone that has replaced an LDP pump for that fault code has never fixed the car with a new LDP pump. Thats why im reluctant to think its a bad pump, go over everything carefully.

 

Thanks for your help. Do you happen to have a picture of the exact location, because I cannot find it for the life of me!!! I have looked under both wheel wells. There is some kind of EVAP canister/filter in the left wheel well, and just a black plastic chamber above the right wheel well around the fuel filler tube, but no pump. I have a diagram for the 2003, and it shows to be under the spare tire, but not in the 1997. (This may be a dumb question since the code is there, but did some models not have a pump?, like 1997 and something else be causing the problem? For instance, Could low engine vacuum (worn out engine? this one has 175,000 miles) at idle cause the code?) Anyway, I don't want to confuse the issue...Any additional help in finding the pump would be much appreciated. (FYI, I bought this car and supposedly only the fuel pump was bad, but once I replaced the pump, it has a noise when you put it in R, and Reverse slips / also seller said it had 140 psi compression, but I only get about 110 psi, so both engine and trans. need help!)

You mentioned it's not always the LDP pump? How have others fixed the code?

 

Yeah, if its not behind the right rear wheel well, its under the spare tire well. Get under the car and take off that plate, the pump should be on top of it. Some A6's have it there as well.
If a car didn't have an LDP pump there would be an EVAP system at all.

If you are having problems with the reverse gear in the trans its a 90% chance you will need a new tranny in the near future. Thats in the sticky above, there isn't a fix because no one in the united states is qualified to re-build that tranny.

 

Just to be clear, by 'right', you mean passenger side (in U.S) correct? There is no removable panel under the spare tire.

 

Yeah the passenger's side (U.S) Thats strange that its not there. I have no idea where it could be then, and i don't have access to the factory repair manuals to look it up now either.

 

Follow up on the solution...Sure enough, as I suspected, there is no LDP pump on an early 1997 A8. The previous owner had swapped the ECU with one dated ( 05.09.98 ), which I can only conclude was looking for the LDP pump. I managed to convince him to send me the original one. When I put the original ECU back in, dated ( 14.01.96 ), the P1470 code went away. Don't know why he swapped them in the first place. Original ECU works fine...

Unfortunately, It still has engine misfire codes (because he sold me a car with a worn out engine, 25 - 40 psi compression when cold, no vacuum leaks (except in the cylinders...hahaha), takes several attempts to keep it running when cold, engine vacuum 6 - 8 in. Hg @ idle, when warm), so I'll be overhauling it soon.

 

Well thats good you found the problem with the EVAP, but damn what a major blow for the motor Maybe Mahle makes some upgraded forged top pistons that should get you some higher compression! That would be cool.