urs4hb

Hey guys im not a big forum poster but was hoping to get some help or thoughts on this allroad ive got.

Diagnosing a 03 Audi Allroad apr chip and all stock
17964/P1556 - Charge Pressure Control: Negative Deviation
No other codes

I just purchased this car with no previous owner history and it being in what seems to me, limp mode or not boosting. The Only code that pops is the P1556/17964 - Charge Pressure Control: Negative Deviation. I've done much testing and Diagnosis with the car such as pressure testing it up to 15psi and it being ok. All related turbo boost controlling parts (n75, bypass valves EX.. have been tested or exchanged with known good units from other cars....they all are in spec. The car runs as smooth as ever. You can hear the turbos lightly spool 3-4 psi or so and then drops off. I checked the waste gate actuators and they seem to be normal and you can hear the flap close in the down pipe. Any thoughts as to having bad turbos or are the precats and cats being so plugged up the turbos cant spool? I get no puffing or weird noises from the turbos either. Also could anything with the exhaust gas check valves (not egr things) on the backside of the cyl heads have anything to do with it?

Another thought is the car I think has a apr chip. I can start the EMCS process threw the cruise button. When doing the EMCS process the CEL blinking 5 times and then blinks twice really fast meaning program 2? No matter how long I hold the set button in it continues this sequence of 5 blinks and then two fast blinks not allowing me to access any other programs such as valet or whatever other programs the chip package came with for the previous owner?

Does anyone know of the possibility of when a new battery was put in or the battery went dead this locked the ecu with the 5 digit code and or put it in valet mode or Security Lockout? Any thoughts on this matter would be great? if you need any more info please let me know.

Thanks

dariussquared

i need to bring this thread back from the dead. I have nearly the exact same issue and am unable to find the cause. Were you able to find it?

2004 allroad with APR throwing P1556, audible boost leak sound. pressure test passes, N75 passes.

Jay Markow

Let me add some meat to this thread.

in the last two days, I replaced both Exhaust Gas Temp sensors with the upgraded boards from Poland (see that thread). We replaced both EGS Boards with no real issues.

With the engine was exposed I had a plan to replaced the Turbo/Boost Control Solenoid and Fuel Injection Pressure Valve.

On start up no codes. On test drive all good through four or five accelerations, then lurches, engine light, ABS, Suspension lights all came on. We limped back, low power lurching.

This AM, I reset all codes to get it out of limp mode. I was able to limp her home, stopping, resetting, any accetlation above bare minumuim casued lurches and same codes.

These same codes came up...

16487 Mass Air Flow P0103 Signal to High
17965 Charge Pressure Control. P1557 Positive Deviation.
16524 Oxygen Sensor B1 S2 P0140 No Activity (this was known, I have new one, just not replacing until I did EGS first).

From Ross Tech wiki site these code show:

16487/P0103/000259 - Mass Air Flow (MAF) (G70): Signal too High

Possible Symptoms

• Probably no serious malfunctions
• Loss of power

Possible Causes

• Wiring and/or connections (short circuit?)
• Mass Air Flow (MAF) (G70) defective

Possible Solutions

• Check wiring and connections
• Check / Replace Mass Air Flow (MAF) (G70)

Special Notes

• In MY 1995-2002 (?) in Europe at VW-diesel-cars G70 had the bad reputation of slowly losing his performance, causing loss of power. It's not a matter of defective or breaking down, but it is filthy / dirty (not easy to clean). You can check functionality by making a log in [01-engine], [meas.blocks-08], group 003 (3e gear, full throttle, from 1700-4000rpm)

17965/P1557/005463 - Charge Pressure Control: Positive Deviation

Possible Symptoms

• Reduced power output
• Limp mode

Possible Causes

• Boost Pressure too High
• Hoses/Pipes incorrect connected, disconnected, blocked or leaking
• Charger Pressure Control defective
  • VNT (variable nozzle turbo): nozzles stuck
• Solenoid Valve for Boost Pressure Control (N75) defective

Possible Solutions

• Check Hoses/Pipes to/between Components
• Check Solenoid Valve for Boost Pressure Control (N75)
• Check / Clean / Replace Charge Pressure Control
  • Check / Clean mechanism for variable nozzles

This weekend, I will do tests, logs and update.

Jay Markow

Update: took it back apart checking on hoses and lines. When I removed the new upgraded 2nd Air hose there was water drops condensation in all three ends of New 2nd Air hose. Testing it, its sealed. Last night at first start up the 2nd Air pump was loud jet engine for a long time. I shut down and restarted and it went away. This AM on start up same thing. Never heard that prior to these repairs. The Bank 1 and 2 Exhaust Gas codes are gone, but the MAF and Charge Pressure come back on immediately. I removed the new PIEDMONT Boost Control Valve. Not sure what to do next.

Info: I have a 2001 Allroad Quattro, have VAG COM, we have done both combis, alt, valve gasket, timing belt, water pump, rebuilt exhaust, rebuilt front brakes (salt, Canadian winters).

The faults I was servicing were 1, 2 Bank Exhaust Gas Temps. They are both gone. Now I have MAF and Charge Pressure in exchange, so my thinking is the new Piedmont Boost Valve OR the added pressure from new Exhaust Gas boards made 2nd Air pump jet engine, and maybe blew something? I did a Throttle body reset after repair but not this AM. HELP?