Power loss and ABS

Hello everyone!


After visiting this forum a few times, I've decided to reach out to you all with my problem.

A4, year of manufacture 1996.
AFN, 1.9 TDi, 81 kW (with Öttinger chip, 96 kW).
Oil change due in 30,000 km.


1. Worry:

Power loss during acceleration. Brief power drops in gears 2, 3, and 4. Occurs on highway driving in 5th gear. Sudden drops in performance, or a complete loss and reduction of speed to 140 km/h.

VAG-COM:

Error:

00575 017
Intake manifold pressure regulation differential (intermittent).

00519 028
MAP sensor - G71.
Short circuit to positive (intermittent).

'I replaced the power supply, but the problem persists, and the same error message keeps appearing.'

Measurement data block 8.

3210/min 48.6mg/h 46.4mg/h 47.2mg/h

to 10

1035mg/h 948mbar 2121mbar 100%

to 11

1970/min 2142 mbar 1254 mbar 44%
3110/min 2142 mbar 2101 mbar 57%
3150/min 2142 mbar 2203 mbar 55%
3700/min 2080 mbar 2142 mbar 64%

The complete. The turbocharger was replaced during the ATM (Annual Technical Maintenance). Therefore, I will exclude the VTG (Variable Turbine Geometry) for now.
Is that the LMM? Or even the solenoid valve?

Perhaps you can make use of the measurement data and tell me what you think about it.

Best regards,
Daniel

Hello Daniel,

The measurement readings are meaningless until all the errors in the error memory have been cleared.
completed.
You should be able to find quite a bit of information on this topic in the forums and databases, or in relevant articles.
Tip: A short circuit to the positive terminal doesn't always originate at the sensor. Have you also carefully checked the wiring?

I checked, and there are no exposed or damaged cables.

I didn't quite express myself clearly... the errors only occur sporadically. In other words, the last diagnostic scan showed no errors whatsoever, despite the problems described above.

Best regards,

Okay, it's not like I only have one problem.

Sure, here's the translation of the text from German to English:

'No. 2'

After having the engine compartment cleaned about a year ago, I tried to absorb any moisture in the area around the ABS control unit. In the process, I disconnected the connector (black with a safety clip). The ignition was off, and the key was not in the ignition switch. When I started the engine after reconnecting the connector, the ABS and central warning lights illuminated...and they are still on today. The ABS is no longer working, and the error memory indicates 'Relay for ABS solenoid valves - J106'.

'Can I order this relay individually and install it myself, or should I leave it to the professionals? Does an Audi dealership handle this, or who should I contact? Three different Audi dealerships told me that the only option is to replace the entire ABS control unit.' That just sounds like a scam to me.


Best regards,
Daniel

DanWos wrote:

Short circuit to positive (intermittent)

... This often indicates a problem with the grounding. It could be a missing, damaged, or incorrectly installed ground strap (connecting the body to the engine/transmission and the battery). If there's poor contact there, the EDC system will measure incorrect values and provide false control signals.

Hello Daniel,

Quote:

After a motor wash 1 year ago, I tried to absorb any moisture remaining in the area around the ABS control unit. In the process, I also disconnected the connector (black with a safety clip). The ignition was off, and the key was not in the ignition switch. When I started the engine after reattaching the connector, the ABS and central warning lights illuminated...and they are still on today. The ABS is no longer working, and the error memory indicates "Relay for ABS solenoid valves - J106".

These could be the errors:
- Faulty wiring connection or excessive resistance in the grounding connection to the solenoid valve relay - J 106.
- Open circuit or short circuit to positive/ground in the wiring between relay -J106 and control unit -J104.
- Faulty relay for solenoid valves -J106 or hydraulic unit -N55.

You could have found this description yourself in the knowledge databases. Please search thoroughly before posting...

Furthermore, I find it strange to drive for a year without ABS when there's a clearly identifiable fault.

Since I had the afternoon off today, I got some help and we started working on getting rid of these troublesome waste products.

- LMM cleaned (with isopropyl alcohol) -> no improvement.
- LMM (loaner unit) swapped out -> no improvement.
- Replaced the new magnetic valve for charge pressure limitation -> no improvement.
- The turbocharger is new, but the variable geometry turbine (VGT) linkage was checked for proper operation -> OK.
- Cat checked (tapped) -> appears to be intact.
- Check all lines of the turbocharging system for leaks or... Damage checked -> OK.
- Valve timing checked -> within the optimal range.

concisely...I'm at the end of my rope , the only thing that comes to mind is to replace the ECU, but that would also mean giving up the performance increase.

Is there anything else that any of you can think of that we might have overlooked?


@MichaelII

Regarding the ABS: Thank you for the information. I did find it in the forum, but my question was whether I can purchase that specific relay individually and potentially install it myself.
And 1 year without ABS... somehow I've always put it off...no time, etc... but now it's the right time and I can finally get my car back in shape... Thanks for your help .


Best regards,
Daniel

DanWos wrote:

- LMM cleaned (with isopropyl alcohol) -> no improvement. - LMM (loaner unit) swapped out -> no improvement. - Replaced the new magnetic valve for charge pressure limitation -> no improvement. - The turbocharger is new, but the variable geometry turbine (VGT) linkage was checked for proper operation -> OK. - Cat checked (tapped) -> appears to be intact. - Check all lines of the turbocharging system for leaks or... Damage checked -> OK. - Valve timing checked -> within the optimal range. concisely...I'm at the end of my rope , the only thing that comes to mind is to replace the ECU, but that would also mean giving up the performance increase. Does anyone have any other ideas about something we might have overlooked?

Hi Daniel,
. . . perhaps one or two specialized articles (e.g., Troubleshooting with VAGCOM, MAF sensor. . .)