Putting the LX into diagnostic mode

[DMAG]

How to Interpret the Diagnostic Mode Displays
by Tommy T.

If your LX has the Electronics Convenience Group option, you can enter a diagnostic mode and cycle through various displays, such as oil pressure, pedal position, and software version, to name a few.

To enter diagnostic mode (refer to your steering wheel controls), depress and hold the compass button (the one with the N and small arrow above it) and musical note button for about 6 seconds with the key in the ON position (doesn't matter whether or not the engine is running). Hold the buttons until you see the display change.

Cycle through the displays using the up/down arrow buttons. Exit diagnostic mode by depressing the compass button.

These screens will appear:


COMPASS RAW: Magnetic heading. A heading of due south would show 180 degrees.
OIL PRESS: Oil pressure in psi
PDL POS: Throttle position, in percent



Shows the last alert active (in this case, the parking brake was engaged while driving). Usually, this will show "abs", since that is the last light to extinguish after startup.
VMM: Version # of the Vehicle (Memory?) Module. Always 319.




19g = 19 gallon gas tank.
Since the gas tank is split into a left and right section that straddles the driveshaft, there are fuel quantity sensors on the left and right side.
LT: fuel quantity sensed in the left tank
RT: fuel quantity sensed in the right tank
AVG: an average of the total fuel quantity. This number is necessary for displaying proper fuel quantity on the gas gauge. See MinL & MinR discussion.
MINL and MINR: So far, the only sensible theory focuses around this excerpt from the service manual, pages 8J59 to 8J60:

"Fuel Level Sending Unit Input - The cluster provides a constant current source to the fuel level sending unit and monitors a return input on a fuel level sense circuit. The resistance through the fuel level sending unit increases as the fuel level falls and decreases as the fuel level rises causing changes in the sense input voltage. The cluster programming applies an algorithm to calculate the proper fuel gauge needle position based upon the fuel level sense input, then moves the gauge needle to the proper relative position on the gauge scale. This algorithm is used to dampen gauge needle movement against the negative effect that fuel sloshing within the fuel tank can have on accurate inputs from the fuel tank sending unit to the cluster."

It appears as if the MinL/MinR values are minimum resistance values the ECU uses in its algorithm to dampen needle movement as the fuel sloshes around. The "AVG" is probably the dampened value used to position the gauge needle.

Observation of the MinL/MinR values shows that:
1) they will reset to 181 after filling up
2) the values will stay at 181 until about 50 pints, then will slowly increase to a max of somewhere around 199 (the highest number reported thus far). Even with very little fuel in the right tank (i.e., hovering around 0, but occasionally fluctuating between 0 to 5 pints), the MinR value will be around 195 to 196.
3) this corresponds with the service manual statement that resistance increases as fuel level falls.

Remarks: There are 2 schools of thought about the units of measure displayed.
--(1) Liters may be appropriate since there are 71.9228242 liters in 19 gallons. Some creative math makes the numbers work, considering that values of 80 left / 72 right are fairly typical after filling up.
--(2) The use of pints appears to be a better fit. There are 8 pints per gallon which means there are exactly 152 pints in 19 gallons. Again, post fill-up values of 80 left / 72 right equate to a total of 152.

Note: The right tank will drain first, followed by the left. There is no interconnect between the two, unless the vehicle is in a turn, in which case, fuel may spill over the top from one side to the other.


Self-explanatory

Note: Vehicles with software prior to version 3.60 will not show the oil can display. If software is upgraded, the vehicle may still be unable to show the oil can display because of an incompatible instrument cluster.



Software version. As of January 2005, the latest version was 3.61 with a date of 7/27/04. Some owners have versions dating back to 2/25/04, v3.54.



Self-explanatory




Self-explanatory

Note: Vehicles with software prior to version 3.61 will not show this digital speedometer.



TEMPAVG: Average outside air temperature. EVIC displays this value when not in diagnostic mode.
TEMPRAW: Measured / uncorrected outside air temperature.

Remarks: If there were no average temperature data point, the EVIC temperature display would change fairly rapidly. The software works to display the ambient outside air temperature, not the temperature of air warmed from an idling engine while stopped. (Member jeffp noted that while creeping along in the snow, TEMPRAW showed 80F when actual outside air temp was 25F)

Lower display: The software is designed to have a delay on the upward count. The downward does not have the delay. Once the lower numbers count up -- the left is seconds and counts up once you're at a steady speed, for a total of 180 seconds -- the right number counts up at a faster rate to 1500. If the temperature is stable, the system will load raw temp data to the data buffer for upcoming update of the TEMPAVG value. The letter indication for stable is S, if incrementing the counter shows I, and when the raw is higher than the avg and the counter has not reached a stable state, it will show H. If more than one condition is met it can show both letters.




LAST VTA TRIG: Current state of the Vehicle Theft Alarm.
LAST WAKEUP: Sensor that "woke up" the vehicle and brought it out of "sleep" mode. The number relates to which sensor was triggered. The sensor sets a single bit in a 16-bit value, corresponding to a decimal number of 0 to 32768, i.e.,

0000 0000 0000 0000 = 0
0000 0000 0000 0001 = 1
0000 0000 0000 0010 = 2 : driver door
0000 0000 0000 1000 = 8 : driver side rear door
0000 0000 0001 0000 = 16 : passenger side rear door
0000 0000 0010 0000 = 32 : passenger door
0000 0000 0100 0000 = 64 : liftgate
0100 0000 0000 0000 = 16384 : keyless entry remote
1000 0000 0000 0000 = 32768 : Placing the key in the ignition

There may be remaining sensors. For instance, the export version has a hood latch sensor which may or may not have its own sensor code.

-- Tommy T.

(Contributors: BrilliantBlackHemi, jeffp, 7thSon, MagnumFreak, one_raven, mrstrike, hemi dawg, KintlaLake, and others)

[Tommy T.]

Updated with different pictures, several changes / corrections / clarifications, with an included MinL / MinR discussion.

On a side note, there's a recently discovered way to read diagnostic trouble codes.

Link

-- Tommy

EDIT: pictures got shuffled around, here's the picture of the "parking brake engaged" display:

[dantodd]

Just a quick update. The fuel level can be higher than 199, I just went to fill up and saw that I was showing 200. I don't know if this is the end of the range or not, I really don't want to test it!

[Boardmandan]

One other trick I found. My software version is 4.07 dated 9/12/05. On the screen with the VTA trig and Wake info, my third line reads this:
>190 Lgt:15
Adjusting the 190 number using the right arrow button allows you to set the light sensor trigger level if you have auto climate control, that turns on the auto headlights (another mod). Lgt: is the amb light reading. The lower the number the brighter it is outside. I verified the setting is retained overnight.

This car has a lot of fun things to discover!

[mr.niftie]

What software is this that I have to request a new version of?

Is it the FCN?

[Jaak]

I get this without going in to the diagnostic mode. It's right next to the temperature display in the list.

[nick_danger]

I get this without going in to the diagnostic mode. It's right next to the temperature display in the list.

Yeah, that's a feature of the newer models...

[Nightshade]

Mine has a neat feature too.. sometimes shows temperature as 54 Degrees C... and the digital spedo shows negative speed.. the oil pressure shows a messed up first digit.. neato.. think my CCN is in need of reflash.. meh.

Yeah, that's a feature of the newer models...

[mr.niftie]

Known problem.

I've had it for over a year now. Happens every time the temperature <0.
A newer flash should do it. Not sure what the latest version is for an '05.

[Nightshade]

Think I have the latest CCN though..

Known problem.

I've had it for over a year now. Happens every time the temperature <0.
A newer flash should do it. Not sure what the latest version is for an '05.

[PA_Hemi]

What software is this that I have to request a new version of?

Is it the FCN?

Did you ever get an answer on this? I can see the oil can and digital speedo in diag mode, and would like to get my software flashed so I can see them in normal mode.

I like the digital speedo because the top of the wheel usually covers the part of the speed range I'm in.

What do I need to ask my dealer? I called him this morning, and he's about as smart as a box of rocks. (minus the box)

Thanks in advance.

[Token]

Mine has a neat feature too.. sometimes shows temperature as 54 Degrees C... and the digital spedo shows negative speed.. the oil pressure shows a messed up first digit.. neato.. think my CCN is in need of reflash.. meh.

Happened to me too. Went back to normal after I did a battery disconnect.

[MagnumFreak]

Did you ever get an answer on this? I can see the oil can and digital speedo in diag mode, and would like to get my software flashed so I can see them in normal mode.

I like the digital speedo because the top of the wheel usually covers the part of the speed range I'm in.

What do I need to ask my dealer? I called him this morning, and he's about as smart as a box of rocks. (minus the box)

Thanks in advance.

The CCN controls the evic display. (Cabin Control Node)

The digital speedo and oil can are only visible in diagnostic mode even in the latest software version.

Good luck on getting the dealer to flash the module. unless you have a specific tsb or problem most won't even touch it.

[PDRT]

Thanks for the great info. Very cool.

[Bubba's Dragon]

man i wish i had this option on my car.