Code P1549

Tiny
DAN07
  • MEMBER
  • 2003 VOLKSWAGEN GOLF
  • 1.9L
  • 4 CYL
  • TURBO
  • 2WD
  • MANUAL
  • 192,000 MILES
Hi guys, I have a mk4 golf tdi ASZ engine and I went through a sizable puddle. Instantly the car went into limp mode. It will reset for a bit but come back. I've plugged it in and I am getting the same faults every time which are

P1549
N75 wastegate bypass regularly valve open circuit/short circuit to ground intermittent.

P1524
Fuel pump relay open/short

P1256 coolant temperature sender open/short

P1672
Fan 1 control open circuit

P1657
AC input/output short circuit to b+

When I erase them these faults come back after a day or so. I've had the n75 valve replaced (genuine) and the ECU pins checked, cleaned the earth under scuttle panel and had the main loom multimeter checked by a VW tech and they are stumped. I'm hoping someone has had a similar issue that could point me in the right direction. Many thanks,
Dan
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Friday, October 23rd, 2020 AT 12:41 AM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 107,696 POSTS
Hi,

When he checked the ECU, what was he checking for? For example, was he checking the wiring condition and the connection or operation of the ECU? Was it checked when the vehicle was in limp mode or after it was cleared? Also, how much water did you hit and how is the vehicle running? I realize it goes into limp mode, but before that happens, how is it running?

Let me know.
Joe
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Saturday, October 24th, 2020 AT 11:38 PM
Tiny
DAN07
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Hi, thanks so much for the response. So he was looking for possible broken wires or signs of water using a multimeter on the 120 pin plug connector. It was checked with faults in the memory but not while it was actively in limp. Then they were cleared after he couldn't find any signs of wire damage.

It wasn't deep water as it was on a flat bit of motorway but enough to go into limp almost immediately. It runs great when not faulting then randomly ill hear the tone of the engine change to a more louder deeper noise and that's when the turbo won't work. If I erase the fault it buys me a few days but then it gets progressively worse. It seems to happen more when I'm slowing down then trying to accelerate. If there's anything else you need just let me know.
His next idea was to run a wire straight from n75 to ECU to see if that made a difference but this seems to have stumped some people.
Thanks
Dan.
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Sunday, October 25th, 2020 AT 2:18 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

I suspect that either there is an open circuit or the bypass regulator is bad. The idea that he checked the connections for water and breaks should have shown an open, but he could have missed it. Since it works for some time and then fails, I have a feeling the bypass regulator is bad, but testing will prove that.

______________________________________

Here are the diagnostics for troubleshooting the problem. However, you need a manufacturer-specific scan tool to do it (VAG). I don't know if your mechanic has one. There are no options for other types of scan tools or programs.

_____________________________________

2003 Volkswagen Golf (1J1) L4-1.9L DSL Turbo (ALH)
With Manufacturer's Scan Tool
Vehicle Powertrain Management Computers and Control Systems Testing and Inspection Scan Tool Testing and Procedures Output Diagnostic Test Mode (DTM) With Manufacturer's Scan Tool
WITH MANUFACTURER'S SCAN TOOL
Function 03: Output Diagnostic Test Mode (DTM)

Performing Output Diagnostic Test Mode

Special tools and equipment
- Scan Tool (ST) VAG 1551 or VAG 1552 with cable VAG 1551/3

Test conditions

pic 1

- Main fuses OK.

Pic 2

- The fuses must be OK.
- The battery voltage must be at least 11.5 V.
- All electrical consumers, e.G. Lights and rear window heating must be switched off.

Prerequisites (with air conditioning)
- Vehicle at room temperature, warmer than + 15 degree C (59 degree F)
- A/C on
- Lowest temperature setting and highest blower speed

The Output diagnostic test mode activates the following components in the following sequence:
1. Cold Start Injector -N108-
2. EGR Vacuum Regulator Solenoid Valve -N18-
3. Air Conditioning compressor interrupt
4. Fuel Cut-off Valve -N109-
5. Wastegate Bypass Regulator Valve -N75- for boost control
6. Glow Plug Relay -J52-
7. Glow Plug Indicator Lamp -K29-
8. Relay -J359- preheat coolant, low heat output (man. Trans. Only)
9. Relay -J360- preheat coolant, high heat output (man. Trans. Only)
10. Malfunction Indicator Lamp (MIL) -K82-, Exhaust Warning Lamp -K83- (MIL is shown in the 1551 display, however; -K83- Exhaust Warning Lamp is the actual component being tested)

NOTE:
- Activation of individual control elements is limited to 30 seconds. But can be stopped at any time by pressing button.
- Ignition must be switched off before repeating Output Diagnostic Test Mode.

Work sequence
- Connect Scan Tool (ST) VAG 1551/(VAG 1552). With engine idling select Engine Control Module (ECM) with "Address word" 01 (Connecting Scan Tool (ST) and selecting ECM. See: Computers and Control Systems > Scan Tool Testing and Procedures > Connecting VAG 1551 Scan Tool)

Indicated on display:

Rapid data transfer HELP
Select function XX

- Operate Scan Tool (ST) and advance through program sequence by following display.
- Press buttons -0- and -3- for "Output Diagnostic Test Mode" (DTM).

Indicated on display:

Rapid data transfer HELP
03 Output Diagnostic Test Mode (DTM)

Activating Cold Start Injector -N108-:
- Press -Q- button to enter input.

Indicated on display:

Final control diagnosis ->
Cold Start Injector -N108

Activating the valve, influences the noise of combustion considerably (pre-ignition).
If no changes in the combustion noises are heard:

- Check injection adjuster control range. See: Computers and Control Systems > Component Tests and General Diagnostics > Diesel Injection Timing Control Range, Checking

Activating EGR Vacuum Regulator Solenoid valve -N18-:
- Press -> button.

Indicated on display:

Output Diagnostic Test Mode
Exhaust Gas Regulator Valve -N18

Valve must click.

NOTE: It is difficult to hear the valve click due to engine noise. Determine valve operation by feel (touch).

Valve does not click:
- Check EGR Vacuum Regulator Solenoid Valve -N18-

Activating air conditioning compressor interrupt:
- Press -> button.

Indicated on display:

Output Diagnostic Test Mode ->
A/C Compressor interrupt

Air conditioner compressor switch-off is checked.
The test step is also called on vehicles without air conditioner system.

A/C compressor must stop within 5 seconds (visual check) then start approx. Every 5 seconds and then stop.

If A/C compressor does not switch off:
- Check signals from/to air conditioning system. See: A/C Signal > Component Tests and General Diagnostics > A/C System Signals, Checking

Activating Fuel Cut-off Valve -N109-:
- Press -> button.

Indicated on display:

Output Diagnostic Test Mode Fuel cut-off valve -N109

The engine must stop.

If engine does not stop:
- Switch off ignition.
- Unscrew fuel shut-off valve and remove any metal particles or dirt, item 4.
- Repeat Output Diagnostic Test Mode, if engine will not stop replace Fuel Cut-off Valve -N109-.
- Continue Output Diagnostic Test Mode with engine stopped and ignition switched on.

Activating Wastegate Bypass Regulator valve -N75-:
- Press -> button.

Indicated on display:

Output Diagnostic Test Mode ->
Wastegate Bypass Regulator Valve -N75-

The solenoid valve must click.

NOTE: The clicking operation of the valve is difficult to hear and is therefore best checked by touch.

If the solenoid valve does not operate:
- Check charge pressure control solenoid valve -N75-:

Activate Glow Plug Relay -J52-:
- Press -> button.

Indicated on display:

Output Diagnostic Test Mode ->
Glow plug relay -J52

Vehicles through MY > 2001

Relay must click.
Switching relay on and off can also be observed by the brightening and
dimming of the interior light as a result of glow plug power consumption.

If relay does not click:
- Check glow plug relay:

Vehicles from MY 2002>

NOTE: This engine has a Glow Period Control Module - J370- installed. It is not possible to optically and acoustically check the activation, this is only possible by connecting a current pick-up clamp to the glow plug wiring. See: Glow Plug > Component Tests and General Diagnostics > Glow Plugs, Checking

Continued for all vehicles
Activate glow period warning lamp (K29):
- Press -> button.

Indicated on display:

Output Diagnostic Test Mode ->
Glow Plug Indicator Lamp -K29

Glow Plug Indicator Light -K29- does not blink:
Glow Plug Indicator Light -K29- must blink.
- Check Glow Plug Indicator Lamp -K29-:

Activating Relay for low heat output -J359- (only on vehicles with manual transmission):

- Press -> button.

Indicated on display:

Output Diagnostic Test Mode ->
Low heater output relay -J359

The relay must click.

If the relay does not click:
- Check low heat output relay:

Activating Relay for high heat output -J360- (vehicles with manual transmission):
- Press -> button.

Indicated on display:

Output Diagnostic Test Mode ->
High heater output relay -J360

The relay must click.
If the relay does not click:
- Check relay for preheating coolant, high heat output -J360-.

Activating Malfunction Indicator Lamp (MIL) and Switch -K82-:

- Press -> button.

Output Diagnostic Test Mode
Malfunction Indicator Lamp (MIL) Indicated on display:

MIL must flash.
MIL does not flash:

- Check Malfunction Indicator Lamp (MIL) and Switch -K82-:
- Press -> button.

Indicated on display:

Rapid data transfer HELP
Select function XX

- Press buttons -0- and -6- for "End output" and confirm with -Q- button.
- Switch off ignition.

______________________________________

Note: The directions check several different components, the wastegate bypass regulator is one of the things.

Let me know if this helps or if you have other questions.

Take care,
Joe
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Sunday, October 25th, 2020 AT 6:18 PM
Tiny
DAN07
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I do have access to VW special tools. So I will get them to try the test plan and report back. Thank you so much for taking the time to get back to me.
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Monday, October 26th, 2020 AT 1:51 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 107,696 POSTS
Hi,

You are very welcome. If you have a chance, let me know what you find. I'm certain this will end up helping others in the future.

Take care,
Joe
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Monday, October 26th, 2020 AT 6:09 PM

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