# FAQ 1.8t - Vag Com Tips and Tricks



## groggory (Apr 21, 2003)

Hey everyone,

Time for another FAQ. This one will be in regards to 1.8t specific vag com tips and tricks.

I'm not a vag com expert, but I know many of you are. Please pop in with tidbits you know and I'll sort them into a readable FAQ. I'll also be linking to this FAQ from my main FAQ.

Thanks,

Greg

Organization of the topic...

If you want to learn how to do anything with the vag com the obvious answer is to go to the vag com manual on ross-tech.com and read it. It's all there (it is, really!). But that's not my goal here. My goal is to make an FAQ that is built around people's intended purpose in using the vag com to achieve something. So let's build this thread around achievements.

Some ideas for achievements


 How do I read codes?
 How do I determine optimal shift points
Read this
 How do I log data?

Note: In order to have a log that will be valid, you will need to see at least a 3rd gear wide open throttle run from about 2500rpm until redline. Any lifting of the throttle during the run will result in inaccurate A/F numbers for the purpose of our evaluation.

Official Manual
Data logging guide @ Audizine
 *How do I align my DBW throttle body?*


> Procedure for performing a Throttle Body Alignment on DBW Cars using KWP-1281:
> (Check to see if the engine speaks KWP-1281 by looking in the top left of the Open Controller Screen Some examples of KWP-1281 engine controllers are 2000+ Golf/GTI/Jetta/New Beetle/Audit TT 1.8T)
> 
> Turn the key on but do not start the car.
> ...



* How do I align my DBC throttle body?*
 *What are measuring blocks? Why do some people call them channels?*
Measuring blocks and channels can be used in place of each other.
* What are some of the more common measuring blocks?*
Ross-Tech - All Measuring Blocks


> *Channel 1: Lambda Correction*
> 
> This is a fuel correction table used by the computer when it senses the car richening and leaning from the programmed air/fuel tables. The numbers will be displayed as a percentage starting from 0% indicating NO fuel correction is needed. This means the car is doing what it has been asked to do. No fuel is having to be added or removed to maintain harmony. The computer can correct for these rich and lean conditions up to 25% or so. Note that seeing numbers higher than 0 does not necessarily mean your car is running dangerously rich or lean just because of a little correction. Positive numbers displayed indicate fuel is having to be added to compensate for lean conditions. Negative numbers indicate fuel is having to be removed to compensate for a richer condition. The lower the numbers the better. Numbers upwards of 20 indicate some real problems that bear much closer attention. Remember that lean is your ultimate enemy. Note: This channel can not be substituted for channel 31 which displays the actual air/fuel ratio. This channel displays the deviance or the correction from the a/f that is requested, but if the incorrect air/fuel is requested by the programming than one could still be running an unsafe air/fuel ratio and the computer would not correct for it. To determine the actual a/f that is being requested and achieved you would defer to channel 31. To determine if the vehicle is having to remove or add fuel to achieve that a/f you would rely on this channel.
> 
> ...



 New car keys
 New cluster
 I want to use water/ meth. What data do I need to collect to tune for water/ meth? How do i collect that data? How do I read it? What's it mean? How can I use this data to improve my water/meth system?
 My car is bucking and feels like it's misfiring. How do I use vag com to figure out why this is happening? What cylinders are misfiring? What are my fuel trims? What is my AFR? What else should I check?
 I want to squeeze more power out of my car. How can I advance timing safely? What do I need to know? How do I read it, etc.
 I want to put in aftermarket seats. They do not have airbags in them (like OEM seats). How do I disable the airbags?


> Check for local regulations before performing any deactivation/reactivation. For example, Germany requires that this must be checked by an authorized test center and entry made in the vehicle documents.
> 
> This information is shared for persons working on cars and need to temporarily disable the airbags, or others with a need to do so (e.g. frequently carrying a small child in the front passenger seat). The airbags are there for safety, I recommend that they normally be enabled.
> 
> ...


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## groggory (Apr 21, 2003)

Testing the MAF, o2 Sensors, and Catalytic Converter

In order to test your MAF, O2 sensors and catalytic converter, check out the following blocks in the "Engine" control module with your VAG-COM. Blocks 002, 030, 032 and 033 are done in "Measuring Blocks" while blocks 036, 034 and 046 are done in "Basic Settings". Let me know if you have any questions about how to run the tests. (_NOTE:_ The following tests are MKIV VR6 specific. If you have a 1.8T or 2.0 engine, the procedure from running the automated tests is slightly different. For a 1.8T engine, see this THREAD for instructions on how to initiate the tests. I'm not positive about the initiation procedure with a 2.0 engine, but from what I've found, with an AEG engine you manually raise the engine speed to between 1800 and 2200 RPMs, and with the AVH and AZG engines, you derpress the accelerator to the WOT (wide open throttle) position to raise the engine speed to ~2000 RPMs.

*Block 002 - Load Registration*
- Check the MAF airflow reading at idle. Make sure the car is running and warmed up and the A/C is off. Go to Block 002 and look in Field 4. The value at idle should be between 1 and 25 g/s. If it's lower than 1 g/s, then there is probably a leak in the intake tubing between the MAF and manifold.

*Block 030 - Oxygen Sensor Regulation*
- Go to Block 030. Field 1 is a three-digit binary code which gives the status of the pre-cat oxygen sensor. Field 2 is the same thing but for the post-cat oxygen sensor. The digits indicate whether or not the sensor heater is working and whether or not the oxygen sensor control is operational and active. The value should fluctuate between 111 (heater on) and 011 (heater off). The last two digits can also fluctuate between '1' and '0', but should be predominantly '1'.

*Block 032 - Oxygen Sensor Control Learned Values*
- Go to Block 032. Field 1 represents the fuel trim at idle (additive) and Field 2 represents the fuel trim at part load (multiplicative), i.e., while driving. The value should be between -10 and +10% (negative indicates the engine is running rich and positive indicates the engine is running lean). If the value is close to +25% (which is the upper limit), it usually means that the MAF is bad. If the value is somewhere betweeen +10 and +25%, it could mean that the pre-cat oxygen sensor is bad, there is a leak in the intake or that the MAF is on it's way out. The value I found for my car (VR6), which has a new 2.0 MAF and new oxygen sensors is +1.6%.

*Block 033 - Pre-Cat Oxygen Sensor Control*
- Go to Block 033. The value in Field 1 represents the pre-cat oxygen sensor control. The value should fluctuate at least 2% in the -10 to +10% range.

*Block 036 - Post-Cat Oxygen Sensor Control*
- Go to Block 036 (this test must be done in basic settings, not measuring blocks). Depress and hold brake pedal to run the automated test. The engine RPMs should raise to around 1400. Field 1 is post-cat sensor voltage. It must fluctuate slightly between 0 and 1V. Field 4 will say either 'TEST OFF/ON' before/while the test is running and either 'B1-S2 OK' (sensor is good) or 'B1-S2 NOT OK' (sensor is bad) after the test is finished. Release the brake pedal after the test finishes.



*Block 034 - Aging of Pre-Cat Oxygen Sensor*

*Update for 1.8t*
You'll need to run the O2 sensor test in Block 034 before you run the cat test in Block 046.
To get the tests to initiate and run with a 1.8T engine, do the following:
*AWD, AWW* - Manually raise engine speed to between 1800 and 2200 RPMs and hold (use a stick or something similar to hold it there steady).
*AWP* - Step on brake pedal and hold. Next, depress the accelerator fully to the WOT (wide open throttle) position and hold.

Other than the different procedures to get the tests to initiate, everything else should be the same as the VR6 tests.
Gary



- Go to Block 034 (this test must be done in basic settings, not measuring blocks). Depress and hold brake pedal to run the automated test. The engine RPMs should raise to around 1400. Field 1 is the engine speed. Field 2 is the catalytic converter temp. Field 3 is the value which tells you how aged the sensor is (not sure what it's called). Field 4 will say either 'TEST OFF/ON' before/while the test is running and either 'B1-S1 OK' or 'B1-S1 NOT OK' after the test is finished. The aging value must be above 0.80. The value for a new sensor is 1.99. The value will decrease as the sensor ages. Release the brake pedal after the test finishes.

*Block 046 - Catalytic Converter*
NOTE: The test in Block 034 must be done just before this test or it will NOT initiate!
- Go to Block 046 (this test must be done in basic settings, not measuring blocks). Depress and hold brake pedal to start the automated cat. test (last approx. 100 secs - the cat needs to be warmed up above a certain threshold for an accurate reading - the threshold is usually 400°C). The engine RPMs (Field 1) should raise to around 1400. Field 2 is the cat. temp. This will also rise during the test. Field 3 is the cat. conversion efficiency. If the cat is good, the value should be below 0.50 at the end of the test. Field 4 will indicate if the cat is good (CAT B1 - OK) or bad (CAT B1 - NOT OK). Release the brake pedal after the test finishes.


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## groggory (Apr 21, 2003)

Output Diagnostic Test Mode (DTM) (function 03)

The Output Diagnostic Test Mode (DTM) is part of the electrical check. The following components and systems are checked via Output DTM:
- Speedometer
- Tachometer
- Engine Coolant Temperature (ECT) gauge
- Fuel gauge
- Brake system warning lamp
- Seat belt warning lamp
- Buzzer
- All liquid quartz displays (LCD): odometer, multi-function indicator (MFI) or digital clock & selector lever position display (automatic transmission)
- Engine Coolant Temperature (ECT) & low coolant indicator warning lamp
- Brake pad wear warning lamp (where applicable)
- Fuel reserve warning lamp
- Oil pressure warning lamp

- If a malfunction is determined when performing Output DTM, exchange instrument cluster.
- If no malfunction is determined when performing Output DTM, check wiring and connections to instrument cluster using wiring diagram.

Output Diagnostic Test Mode (DTM), initiating


NOTE:
- Output Diagnostic Test Mode (DTM) cannot be initiated, or will be interrupted if engine is running or vehicle is moving.
- Use the -C- button to exit the test sequence at any time.


- Connect scan tool VAG 1551, select operating mode 1 "Rapid data transfer", switch on ignition and enter address word 17 "instrument cluster".
- Press -Q- button to confirm input.
- Press -> button until "Select function"is shown in display.

Indicated on display:


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -3- to select "Output Diagnostic Test Mode" function 03.

Indicated on display


Rapid data transfer Q
03 - Output Diagnostic Test Mode


- Press -Q- button to confirm input.

Indicated on display

Rapid data transfer ->
Analog display


After pressing the -Q- button, the following instrument functional checks are carried out simultaneously on VDO instrument clusters and sequentially on Motometer instrument clusters (press -> button to advance through test sequence):
- Engine Coolant Temperature (ECT) Gauge needle moves over complete display range
- Tachometer needle moves over complete display range
- Speedometer needle moves over complete display range
- Fuel gauge needle moves over complete display range

After sweep of display ranges, the following fixed values are displayed:

Coolant temperature gauge:90 °C
Tachometer: 3000 rpm
Speedometer: 100 km/h (62mph)
Fuel gauge: 1/2

- Press -> button.

Indicated on display:


Output Diagnostic Test Mode ->
Combi instrument warning lamp test


The warning lamps for
- Brake system (low brake fluid level, ABS inoperative)
- Coolant temperature/low coolant level indicator
- Brake pad wear (where applicable) 1)
- Fuel reserve
- Oil pressure
- Low washer fluid level (where applicable) 1)

are activated and remain constantly lit.

- Press -> button.

Indicated on display:


Output Diagnostic Test Mode ->
Seat belt warning lamp - K19


The Seat Belt Warning Light -K19- 1) lights up.

1) Instrument cluster must be coded accordingly in order for these warning/indicator lights to function.

Applications: 
vehicles 05.99 > 05.00 
vehicles 05.00 > See: Instrument Cluster / Carrier > Programming and Relearning > Instrument Cluster From 05.00, Coding (Function 07)

- Press -> button.

Indicated on display:


Output Diagnostic Test Mode ->
Signal


The buzzer/chime is activated: a warning tone sounds in intervals.

- Press -> button.

Indicated on display:


Output Diagnostic Test Mode ->
Segment test


All segments of LCD display in speedometer and tachometer are activated and become visible.

- Press -> button.

Indicated on display:


Output Diagnostic Test Mode ->
Coolant, excessive temp test


Instrument cluster VDO:

Safety cut-off (A/C compressor cut-off- is activated approx. 5 seconds later (vehicles with A/C only)

No indication is given in instrument cluster!

Instrument cluster MMO:

Engine Coolant Temperature (ECT) warning lamp lights and warning sound is given.

Safety cut-off (A/C compressor cut-off is activated approx. 5 seconds later (vehicles with A/C only)

- Press -> button.

Indicated on display:


Output Diagnostic Test Mode -> 
END


- Press -> button.

Indicated on display, instrument cluster MMO:


Output Diagnostic Test Mode ->
END


Indicated on display, instrument cluster VDO:


Function is unknown or ->
cannot be carried out at the moment


End Output Diagnostic Test Mode for VDO instrument clusters by pressing -> button.

All actual values are displayed again.

Indicated on display:


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -6- to select function 06, "End Output".

Indicated on display:


Rapid data transfer Q
06 - End Output


- Press -Q- button to confirm input.

Indicated on display:


Rapid data transfer Help
Enter address word XX


The tester is now in basic function again.


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## groggory (Apr 21, 2003)

Post 4


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## groggory (Apr 21, 2003)

Updated. Thanks for the help so far. Please go back and delete your posts to clean up the thread.

:thumbup::thumbup::thumbup::thumbup:


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## groggory (Apr 21, 2003)

Updated to include details of blocks


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## groggory (Apr 21, 2003)

What is the load % in channel 2 use for? 

And also, does anyone have any insight they want to add to the FAQ? I've been helping some friends do data logging recently and have been using this thread a lot. As I've found weaknesses in the thread I fix them or add to it.


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## groggory (Apr 21, 2003)

My apologies to everyone who's used my thread. I had the two values in block 031 switched.

The correct reading is:

Lambda Actual | Lambda Request | ... | ...

I've made the correction in the first post but wanted to bring it to anyone's attention that uses my thread as a reference.

-Greg


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## groggory (Apr 21, 2003)

Nice vag com directions from APR

http://www.goapr.com/support/datalogging.php


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## groggory (Apr 21, 2003)

To measure Timing Advance with Timing Pull factored in, log block 003


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## groggory (Apr 21, 2003)

Added some neat tricks to block 002


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## Borfasul3 (Aug 29, 2016)

Guys need help please...my new 02 pre-cat sensor aging in 0.54,and my second field in block 033 is fluctuating between 0.2 and max 0.89 V, i saw that must be 1.48-1.56V am I right?


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