Caddy (aey) won't start

Hello, I have a Caddy SDI in my garage. I bought this vehicle with a damaged engine. Now everything is back to its original state, but the engine simply won't start. The error memory was read, and an error was detected (quantity control, implausible signal - error code n146).
The vehicle was previously moved using a conventional push, but otherwise everything is fine. I removed the upper part of the engine head to repair the wiring. Was that a bad idea? The engine is running with the fuel shut-off valve bypassed.
Thank you for any response and interest.

Hello,

Based on my gut feeling, I would say you've likely swapped at least two of the cables connected to the fuel injection pump during the repair.
Please measure the resistance between pin 1 and pin 2, and also between pin 2 and pin 3, on the ESP's connector. They should each be approximately 6 ohms.

Best regards, Rainer.

Thank you, Rainer! This morning, I looked at the N146M quantity adjuster circuit diagram.
'Sensors for throttle slide position and injection start valve checked; everything appears to be correctly calibrated, but I will measure the resistances now.'

Hello,

I examined the connectors of the ESP. The result was that Pin 1 (purple/black) + Pin 2 (green/gray) yielded 6 ohms. Pin 2 + Pin 3 (white/green) yielded 5.9 ohms.
While measuring the quantity adjuster N146, a resistance of 1 ohm was observed.
Could it be that you need to clear the error code from the control unit before you can start the engine?
No voltage can be measured on the N109 fuel shut-off valve when the ignition is on.
The man at VAG said that error codes can only be cleared from the error memory if the errors are intermittent. Is that true?

Best regards, Paule.

Hmm, are you sure that pins 1 and 3 aren't reversed?
I don't know if the engine will start with this error code in the memory (or if it will cut off power), but just clear the error memory. If the error reappears when turning on the ignition and during the subsequent EDC self-test, it's likely due to the wiring, or the sensors in the ESP system may have been damaged by a short circuit or other issue during a cable fire (although the measured resistances suggest otherwise).

Best regards, Rainer.

Hi.

Quote:

The error memory was read, and an error was detected (quantity adjuster, implausible signal - n146). The vehicle was previously moved using a conventional push, but otherwise everything is fine. I removed the upper part of the

ESP unit to repair the cables, was that a bad idea? The engine is running with the fuel shut-off valve bypassed.

As long as the engine is running normally (?!?) with the VP 37 and the bypass valve is functioning, it is my opinion that the cables cannot be reversed.
Regarding the polarity of sensors and temperature transmitters, I believe it doesn't matter as long as their connections are not reversed with each other.

During my attempts to troubleshoot the pump, I encountered several error messages and the fuel quantity regulator generated some errors, but after correctly connecting everything, the system started working normally again – although the preheating light continued to blink for a few engine starts.

Wasn't there a story once about parking violation tickets being entered as "incorrect" by mistake?

First of all, thank you for this interest.

I had to have the car towed to VAG once with my friend, and now it's half a meter longer.

Tomorrow morning, he's going to run the diagnostic tool to see what results it shows.

Ulf, what do you mean by 'there was a story about that once'?
Under what circumstances are 'parking violation' errors recorded as 'incorrect'?

Greetings to you all.
Paule.

Hi.

"In some (possibly certain?) TDIs, the fuel injector, which is incorrectly identified as faulty, may cause the engine to rev up unnecessarily after starting, which can then affect the actual fuel pump (or its control)."

I'm not sure if this also leads to incorrect error entries --> browsing the error database...

Hi
Yesterday, I had to have the Caddy towed to a VAG (Volkswagen Audi Group) service center. There were 4 error codes: fuel shut-off valve, speed sensor (G28), fuel injector control valve, and glow plug system.
'The mass airflow sensor could not be deleted. While they claimed it was necessary for the system to function, the Bosch technical manual for VE ESP states: 'A separate shut-off device (ELAB) shuts down the engine, for example, if the mass airflow sensor fails.' So, what's correct?'

While pushing the car into the garage, I let the engine run for a moment and then turned on the ignition. He then started up, and immediately turned off again; I tried this several times, but it was always the same.

Upon arriving at the garage, I checked the G28 speed sensor. Pin 1+2 should read approximately 1 kOhm, but it's reading 1.18 kOhm. Does anyone know if this is still within the tolerance range?

I also checked the connection from the EDC to the G28. It was working, but there seems to be an issue with the shielding. Normally...
The shielding connects to ground (mass) for direct injection (according to the VAG wiring diagram). In this case, however, it connects to pin T80/71 on the control unit.
According to the wiring diagram, the (T80/71, brown/red) wire should be connected directly to the 156 ground terminal.
The same applies to the needle drive mechanism. The shielding there also uses T80/71.
Perhaps the EDC only releases the shielding later. Does it control it?
Do you really think the engine won't start because of that?

I then removed the G28 sensor for speed, and everything appeared normal.
Does anyone know how I can test the G-28 in some way before I reinstall it?

I've also heard that the engine won't start without the G28 sensor, but this manual also contains something interesting: 'For example, if the speed sensor fails, a substitute speed is calculated from the timing of the injection start signals from the throttle position sensor.' Does that apply to us as well?

Thank you, I just needed to vent .
Paule.

Hello,

If the G28 sensor fails, the engine will stall. The control unit (ECU) does not calculate a substitute value. Since it starts when you connect it to you, but then immediately turns off, it can't be the G28.
Was the instrument cluster also checked for error codes (regarding the immobilizer)?
Perhaps the immobilizer is no longer properly configured with the engine control unit.

Hello,


It can't be the immobilizer because...
First, I would say there's more room for error in the diagnosis.
have(17978)), and also, I asked VAG, and they said that this is not the problem.
This is the immobilizer system that uses an inductive key.

The motor can also run without the G28 command; simply apply power to the kill switch and it will start.
'Then, increase the voltage. Connect the cable to 12V while keeping the throttle held, until the motor runs smoother, and then release the throttle completely.' It runs without a speed sensor, but it doesn't accelerate.

'Thank you for your reply, nonetheless.'

Hello,

If I start manually overriding the sensors and actuators, then I wouldn't need a G28 either.

The answer referred to the normal operating state, not to manual interventions in the actuators. And in this case, the engine will not run without the G28 signal.

Hello everyone,

Sure, I just bypassed the electronics.

Okay, so I'm going to try starting the engine while towing it, using a modified G-28.

Thank you very much for the tip!

Hello.


Okay, I've now completed the test, but before that, I positioned the pump head onto the previously marked locations. Let it be towed, put it in gear, then turn on the ignition. Nothing, not a single sound.
'Disconnected the Drehzahlgeber G-28 and reconnected it, but still no sound from the motor.'
Arrived at VAG, cleared the error memory, but still no sound.
The fuel shut-off valve N109 now receives 12V when the ignition is on. When the starter is engaged, there is no more power to the N109 connector.
I checked this on a VW Vento 1Z, but there is power when starting it.
The VAG technician suggested re-entering the key's coding, which could potentially cause damage, even though there are no error messages.

Now, a question: Can you achieve the same results using a diagnostic device purchased online?

Then it's worth getting this tool, but how?

I am very grateful for any response.

Hi Paule,

Hello, to perform login/adaptation, VAG-Com must be registered.
The free, downloadable version can only read measurement data blocks and error codes.

Best regards, Rainer.

Hello.

Is there a wiring diagram or pinout for the adapter available anywhere?