AJT Errors: Troubleshooting Codes 17969, 17970, 17971

Good day! I couldn't find an introductory thread, so I'm going to jump right in, even though I'd rather not.

"T4, manufactured in 2001, started with a slight hesitation and has since been running at a constant 1200 RPM after starting (doesn't respond to the accelerator pedal), and the glow plug light is blinking."
After clearing all errors and performing a new diagnosis, VCDS displays these three error codes (as is known from other cases, even after just turning on the ignition).

Error code: 17969.
Set point N146, control difference.
Possible causes:
Fuel injection pump failure.
Power outage or short circuit.


Error code: 17970.
Set point N146, upper limit value.
Possible causes:
Quantity setting (N146) defective/blocked.
Upper limit reached.


Error code: 17971.
Quantity setting N146, lower limit value.
Possible causes:
Quantity setting (N146) defective/blocked.
Lower price target reached.

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

"I have shamelessly copied this from an overview here."

Here are some additional potential causes and error possibilities that I found:
"Fuses (numbers 14 and 15 on the T4, as I understand it) are defective."
Flow controller not configured.
--> Fuses are okay, and I don't know how the quantity regulator could have suddenly adjusted itself while driving.


I checked the wiring between the MSG and ESP (okay) and did some temporary connections while the engine was running at 1200 RPM (no change in engine behavior).

Values for part number MWB 019 (ignition on, engine off):
Stop voltage surge: 3,000V (expected range: 0.540-0.880V).
Starting voltage: 4.220V (target range: 4.100-4.880V).
Even though the latter value falls within the specified tolerance, it still displays all three errors: 17969, 17970, and 17971.

Okay, I've already mentally prepared myself to expand the ESP and, with the help of the excellent instructions found here, disassemble and verschandeln it.
A rather unfortunate drawback is that, in order to prepare the engine management system (EMS) and subsequently adjust it during assembly, it is necessary to determine the fuel injection quantities at idle with a warm engine.
"I'm having trouble here because the motor either isn't running or is spinning at approximately 1200 RPM."
Therefore, the alternative measurement run described is also not possible.


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

"Here are some questions:"
Is there another possible cause for the 3,000V reading from the MWB019 related to the stop switch, such as the MSG (Main System Module) incorrectly controlling the MSW (Motor Switch) due to a sensor error that isn't displayed in VCDS?
(For example, the temperatures displayed on the MWB devices all seemed reasonable.)

Can I determine the injection amount preliminarily at the current, unchanged idle speed, and then adjust it while returning the speed to the same value?
And if so, how exactly do I need to aim?
Alternatives to this approach if the answer is no?
Bosch service, huh?

Are there other possible causes besides the blocked MSW (Main Sewage Well), and how can I check, narrow down, confirm, or rule them out?


Okay, just two more additions:
"The car had previously been running perfectly and felt like it had more than the 88 horsepower stated on its documents, but it was emitting a lot of smoke that would make anyone's stomach turn."
No measurable oil or water consumption; I am confident that the engine was running lean and is still running lean.
The start date for the funding was and is correct, and has been verified multiple times.

"2.) I am certain that no 10-cent tuning module is installed. At least, I found nothing on the connector between the ESP and the wiring harness (which, as far as I can tell, is where it would likely have been installed)."


I hope you can help me out during this difficult time.
Replacing parts based on guesswork or trial and error until something eventually works again, especially when the cause is unknown, isn't really my style, not to mention the costs involved with components like an ESP or an MSG.
I'm more of a diagnostic type person.
Unfortunately, I haven't had the bus for very long either; I've only driven a few hundred kilometers with it. And I also quickly borrowed a laptop with VCDS from a former colleague to jump right into this (well, have to jump into this) without first getting familiar with it in a playful and non-critical way.

The Autoscan feature is also missing.

Hi there.
I would still check for a broken cable, specifically at the individual connectors leading to the VP37 and also at the transition point between the body and the engine.

I've experienced something similar with a Golf 3 and a 35i TDI.

Quote:

The car scan is also missing...

Yes, I'm sorry, this is the first time I've heard of it, so I need to do some research and try it out.

Quote:

I would still look for a broken cable, checking the individual connectors to the VP37 and also in the transition area between the body and the engine...

Okay, good point, thanks. I checked the cables between the MSG and ESP modules for continuity and measured the ground connection, but I didn't check the connections at the ESP module itself.

Even with using a multimeter, you can be misled. Ultimately, I found the damage by cutting open the sheathing and visually inspecting each individual wire. Once, it was really bad: the insulation looked fine on the outside, but the wire inside was broken.

Okay, thanks in advance, I can handle that.
It's not just around the corner; the garage with the car is quite far away. It's not worth the trip for just half an hour of work. I think I'll have time at least by the weekend, and hopefully I can also figure out how to do the car scan.

Oh dear, I hope this works like that...:

VAG-COM Version: DRV 311.3-S


Vehicle type: 7-seater VW T4 Transporter.
Scan: 01, 02, 03, 08, 15, 17, 19, 25, 45, 56.

Address 01: -------------------------------------------------------
Control unit: 074 906 018 AK
Component: 2.5L R5 EDC 0000SG 3320
Encoding: 00002
Shop #: WSC 25900
WV1ZZZ70Z1X120608 VWZ1Z0A1237014
Sure, here is the translation of the text from German to English:

"2 errors found:"
17971 - Quantity setting (N146), lower limit value.
P1563 - 35-10 - - - Interrupted.
17969 - Quantity setting (N146) Control difference.
P1561 - 35-00 - -
Readiness: Not applicable.

Address: Skip 15 airbags.

Address 17 -------------------------------------------------------
Control unit: 7D0 920 803 B
Bauteil: T4-KOMBIINSTR. VDO V26
Encoding: 01151
Shop #: WSC 00006
Sure, here is the translation of the text from German to English:

"One error found:"
01314 - Engine Control Unit (ECU)
49-10 - No communication - Interrupted.

Address 19 -------------------------------------------------------
Control unit: 6N0 909 901
Component: Gateway <-> CAN 0001
Encoding: 00000
Shop #: WSC 35110
Sure, here is the translation of the text from German to English:

"One error found:"
01314 - Engine Control Unit (ECU)
49-10 - No communication - Interrupted.

Address 25 -------------------------------------------------------
Control unit: 6X0 953 257
Component: IMMO 0008
Encoding: 00001
Shop #: WSC 51542
WV1ZZZ70Z1X120608 VWZ1Z0A1237014
No error code found.

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

"Ende" translates to "The end" in English.

Splinters in the eye, broken feather, etc.

Sure, here's the translation:

"Briefly and concisely, thank you."
Okay, so let's disassemble and take it apart.

Is there a way to determine the values for the settings during reassembly, even though the engine only runs at 1200 RPM?

Cleaning is probably possible, but are the feathers available as a replacement part?

I would start by removing the cover from the flow meter. This can be done even while it's installed, and if everything looks okay there, then I would consider other possible causes.

Here is a technical article on how to disassemble the VP37.

Okay, understood, thank you.
I read the article; I can handle that.

Hi there,
Since the engine is running at a kind of emergency speed of 1200 rpm, it seems that the metering unit itself is still functioning. Therefore, do not remove the pump or the metering unit for now.
I would do the following:
- Check the ESP - MSG connector (usually round, 7-pin) for voltage values on the control unit side and resistance values on the pump side. You can find the target values in the relevant manual. While doing this, also apply varying loads to the cable and connectors.
- Read measurement data blocks: 001 when the ignition is on and in limp mode, 019 when the ignition is on.
- Only after presenting the data should you check the sender in the quantity control valve (remove the cover of the built-in injection pump, etc.).
hg
Herbert.

Hello Herbert, thank you for your input as well. However, I must admit that I don't quite understand what you mean by that:

Quote:

Check the voltage values on the control unit side and the resistance values on the pump side.

Between the ESP (Electronic Stability Program) and the wiring harness, there's a 10-pin connector. On the wiring harness side, the cable runs to the control module (MSG).
Can I actually disconnect this connector and take voltage readings there?

Since I haven't found the target values yet: what are we measuring? Do the specifications include the pin assignments for what is being measured, or are we measuring relative to ground?

Regarding the pump side, I measured resistance values, but I may have forgotten to write them down above.
I measured 6.1V between pin 2 and pin 1, 6.3V between pin 2 and pin 3, and consequently 12.2V between pin 1 and pin 3. However, according to the information in the T4 Wiki, this last value doesn't seem to be a relevant measurement.

Yesterday, I also implemented Rudi's suggestion to measure the voltage from each wire at the connector to ground (GND) on the ESP. I found that all wires showed an open loop (OL), except for pin 8, which showed a reading of 7.9-8.0 Ohms.
However, I can't draw any conclusions from this because pin 8 is not shown in the schematic diagram on the T4 wiki.

It remains difficult.
I will take home the task of measuring the voltage at the connector between the wiring harness and the ESP (Electronic Stability Program) unit. I will do this if I know what to measure and how; otherwise, I will simply remove the cover.


I had already read out the measurement data blocks, here are the data:

Quote:

Values for part number MWB 019 (ignition on, engine off): Stop voltage surge: 3,000V (target range: 0.540-0.880V). Start voltage 4.220V (target range 4.100-4880V).

For MWB001, it looks like this:
Ignition on, engine off.
1: 0/min
2: 0.0 mg/R
3: 3.080V
4: 21.6°C

Start the engine.
1: 1224 RPM (Revolutions Per Minute)
2: 0.0 mg/R (this doesn't seem plausible).
3: 3.020V
4: 34.2°C


PS: I would really appreciate it if you could explain the background of your considerations, tips, and suggestions to me. I don't want to be a passive executor; instead, I want to understand the system, the technology, VCDS, and how to use it, purely for my own understanding and independence, and perhaps even to be able to help others with it someday.
Therefore, I eagerly absorb your input, but hopefully I won't have to experience everything firsthand, so I need to learn all of this from others.
Currently, I'm even struggling with the borrowed laptop and VAG Com, which is quite a mundane problem.
Given my complete lack of experience with Windows, no one would have believed that after a quarter of an hour of struggling, I actually managed to fully highlight the Autoscan section so I could copy and paste it here without an internet connection.
But that's enough spam for now; things will get better.

Quote:

Values for part number MWB 019 (ignition on, engine off): Stop voltage surge: 3,000V (target range: 0.540-0.880V). Start voltage 4.220V (target range 4.100-4880V).

I wouldn't have thought the engine would even run with that.

Mechanically, the start/stop positions are correctly engaged when you look at the fuel metering unit and someone turns on the ignition? Ignition off: The fuel metering unit should be able to be pushed all the way down (full throttle) with your finger, and upon release, it should immediately snap back completely.

I will definitely check that out, thank you. But it probably won't be before Saturday.
I'm excited to see! / I'm looking forward to it!

The T4 Wiki is correct. The resistance values at contacts 1 and 3 relative to contact 2 appear to be normal (Ohmic resistance of the sensor coil and reference coil). At the opposite contacts from 1 and 2 (MSG side), there should be approximately 2.5V relative to ground when the ignition is on.
You'll probably need to remove the cover of the fuel injection pump to inspect the sensor. Make sure everything is verschandeln beforehand, and don't forget to take pictures. Don't start unscrewing things haphazardly.
hg
Herbert.