|
||
|
||
|
![]() |
#1 |
This is my second home
Rover75 and Mreg Corsa. Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 21,753
Thanks: 341
Thanked 3,660 Times in 2,924 Posts
|
![]() Many members have asked about the Diagnostics Routine accessible via the trip button. There are umpteen links used to get this info, but the detail provided is either incorrect or confused. I've spent some time going over the various sections and managed to simplify a lot of it. The fuel gauge stuff was totally mixed up but thanks to an investigation by Jules this now makes some sense. The routine for correcting the OBC fuel consumption will allow the screen to give data exactly in line with manual estimation using the brim-to-brim method. If your driving regime remains unchanged, you should be able to drop the exercise completely. This requires practical verification.
(Verification not been confirmed to date: December 2021) ************************************************** ******************************** This is my revision dated 4 January 2021 with some comments added previously ************************************************** ******************************** To those who've already done so, or plan to copy/paste the following document onto YouTube, etc. or use it to demonstrate the technique in video format I say, please do the honorable thing and acknowledge who did the work and where it comes from. I will contact those publishing my work via the YouTube, etc. public comments system and request a simple acknowledgement. Many thanks, T-Cut 30 April 2017 ************************************************** ********************************* All models, with or without the High Line/Onboard Computer, will display diagnostic mode on the lower (Trip) screen. How To Use Diagnostic Mode The following information originates from an old BMW document and may be ambiguous in parts due to differences in the MGR system. I've made the instructions easier to follow than the original. Any errors in this revised data are mine. Failure to activate the diagnostics routine is usually due to not pressing the button fast enough. If pressing is delayed for more than a second or so, it will revert back to the standard trip display. There are bits of it I don't yet understand, but most of the useful stuff is explained. Enable Trip Screen Diagnostics: a) Put key into ignition and turn it to position 1 (instruments activated). a2) If you intend driving with diagnostic mode active, start the engine now. b) Press and hold the trip reset button. This is the button sticking out near the speedometer. c) Your LCD display will show "test 1.-" d) Immediately press the reset button every half second until you get to "test 19.-". (19.0 allows access to diagnostic mode) e) The display will now show alternating "Log 1 -on" / "Log 1 -off" f) While it shows "Log 1 -off" press the reset button and. . g) With no delay press within a half second (repeatedly if necessary) to get to the required section. h) The screen will appear similar to the earlier one, but is a different series. Keep pressing every half second to select one of the following functions (there is no title on screen). It's OK to drive the car with any particular diagnostic screen active (eg. coolant temperature). If it's displaying time, engine or speed related data, this will change in real time. DO NOT be tempted to swap between screens while driving! Turning off the ignition ends the diagnostic session. 1 Car, Engine and Cluster Data 1.0 VIN serial number 1.1 K-number 1.2 Cluster Part Number 1.3 Coding (04)/diagnosis (52)/bus index (10) 1.4 Week of manufacture (eg. 1200 = week 12)/year of manufacture (eg. 2000) 1.5 Hardware number (eg. 09) and Software number (eg. 11600 = 16.0) of IPK. 1.6 Injection Status-number of cylinders-motor number 2 Cluster System Test 2.0 Activates the gauge drivers, indicators and LEDs to confirm function. When function 2.0 is selected, the instrument pack provides a check of the warning lamps, major and minor gauges, displays and illumination functions. The gauge pointers are driven through their full arc and back again to check operation. All warning lamps are illuminated to check that none of the LEDs have failed. All yellow and red pixels of the message centre are flashed on and off in a chequered pattern to check that all elements of the display are functional. 3 Service Inspection (SI) Data 3.0 Fuel Used (in liters) since last Service Inspection 3.1 Periodic inspection days; elapsed days (since last SI) 4 Momentary Consumption 4.0 Momentary fuel consumption in litres/100km (eg. 0145 = 14.5 litres/100km) 4.1 Momentary fuel consumption in litres/hour (eg. 0018 = 1.8 l/hr) 5 Distance Gone Consumption 5.0 Average consumption in litres/100km (eg. 082 = 8.2 litres/100km) 5.1 Calculate distance ( km) to refuel (momentary distance to go) 6 Fuel Level Sensor Outputs in litres (Fuel tank has left and right side sensors) 6.0 Fuel levels both (eg: 109330 means left half sensor = 10.9 litres; right half sensor = 33.0 litres) 6.1 Total tank level (eg: 0439 is 10.9+33.0 = 43.9 litres) 6.2 Indicated value with diagnostics: The Test Number (6.2) is preceded by 1, 2 or 3 (eg. 1-6.2 or 2-6.2 or 3-6.2) If first digit is 1 - both sensors are OK. This is followed by three left signal digits, then three right signal digits. If first digit is 2 - one sensor has an error. Side in error will display - - 0 . Functional side will show its three digits If first digit is 3 - no sensor signal, no display. Probably - - 0 - - 0 (Needs confirming --- T-Cut) EDIT 7 October 2019 Section 6 The following comments require a further update based on tests on Section 6 conducted by members during 2019. At this point, I haven't had time nor inclination to include this info, so the following is even more tentative. ************************************************** ************** Members who have had a go at this may have noticed that the routines for the fuel tank and sender units (Section 6) seem to be different from the instructions. Up to now, I hadn't ventured into the Test 6 part, but having now done so, I can report some observations. Firstly, I think the instructions for Section 6 are wrong. I originally interpreted them from BMW documentation, from comments made on a BMW forum and from reports by members of the 75/ZT forums. In fact I now believe that the MGR version does not differentiate each sender's output, but simply displays an integral. It may well display a warning that one or both senders are faulty (the 1_6.2, 2_6.2 or 3_6.2 display), but more than that I now have doubts. In my own case, the displayed figures under each of the Test 6 subsections were the total fuel content. This varied significantly in real time when the car was rocked side to side. This shows that the floats were responding to the changing liquid surface. The integral is given in litres. When I converted this to gallons and used the average fuel consumption shown by the OBC, the calculated range was identical to that shown by the OBC. This proves the figures are total content only. I suspect the original instructions were basically what the BMW diagnostics system showed. The MGR version seems to have been simplified somewhat. EDIT 4 January 2021 This note follows a forum post regarding the often reported erratic fuel gauge issue. Fuel gauges are frequently said to show far less tank inventory than is known to be present. Sometimes, the gauge rises or falls for no obvious reason. The way the fuel gauge operates gets a lot of discussion. Some say there’s a calculation involving the current fuel usage rate that causes the gauge to show levels different from what’s known to be in the tank. The flowing thread suggests perhaps the gauge needs a periodic ‘software reset’ to re-establish its accuracy. Perhaps there’s a bug? https://www.the75andztclub.co.uk/for...d.php?t=310283 Disclaimer: You conduct a Software Reset at your own discretion, but we do need more data on what this option does. *************************************** 7 Temperatures and Speeds 7.0 Coolant/Engine temperature - changes every whole degree Centigrade. (eg: 021+ is 21°C) 7.1 Ambient/Outside temperature - changes every 0.5 degree Centigrade. (eg.125/130/135 is 12.5°/13.0°/13.5°C) 7.2 Engine speed / Current (RPM) 7.3 Vehicle speed / Current Speed (km/hour) 8 Values of 7.0 to 7.3 in HEX form (Unknown) 9 Battery 9.0 Battery Voltage (eg: 137 = 13.7v) 10 Country Code This is just a list. There may be a code displayed for each, which I don't have. I haven't physically checked. 0 = Germany 1 = Great Britain 2 = USA 3 = Italy 4 = E (?) 5 = Japan 6 = France 7 = Canada 8 = Australia/ ** (?) 11.0 Unit code (?) 12.0 Not used 13.0 Gong test This tests the lights on gong which chimes when you open the door. The same gong is used in the speed limit warning for models with the trip computer. 14.0-14.4 Error memory: if 000000 no error in memory 15.0 - 18.0 not used 19 Lock Status: unlocks functions in range 1-18 and 20. 19.0 Log1-On/Log1-Off Locks/Unlocks diagnostic regime: To access, press button when Log1-Off shows. You've already done this section to access the data anyway. 20 Correction Factor for OBC Fuel Consumption Display 20.0 The Factor is displayed numerically in the form ABCD (Thousands/hundreds/tens/units) The formula for the Factor = Indicated Consumption x 1000 / Measured Consumption For more details on this see below. 21.0 Software Reset Resets some OBC settings. Primarily an IPK factory reset in the event of a configuration error. It also resets any error in the ambient temperature sensor value and resets the Correction Factor to default in the fuel consumption calculator (Section 20). No significant changes will be brought about by a Software Reset. EDIT 29 December 2021 The Software Reset function may be effective in fixing electronic 'glitches' in the fuel gauge, as evidenced by a single report (thus far) described here: https://www.the75andztclub.co.uk/for...d.php?t=310283 ********************* This completes the description of Diagnostic Mode functions. If applicable, you may now drive the car with the selected display showing for the duration of the journey. Turn off the ignition to exit Diagnostic Mode. ******************** More on the Section 20: Correction Factor for OBC Fuel Consumption Display The indicated consumption should be established by running the system for several hundred miles, preferably a thousand or so without resetting the OBC at any stage. The longer you allow the un-reset system to operate, the more 'accurate' is the indicated consumption. Determine the measured consumption using brim-to-brim calculations over a similar period. Now calculate your more accurate factor using the formula above. These digits are what you insert for ABCD. Press the button to show 20.1 which allows the units (D) to be set. The display counts down from the current figure and cycles until you press at the required one. This sets it and the display will advance to 20.2 20.2 This allows the 'tens' (C) to be set as above. When you press the set button, the display advances to 20.3 20.3 This sets the 'hundreds' (B) and then the 'thousands' (A). Each digit is set in succession by a single press. After setting (A), the display advances to the next function (21.0) Let's say that the display currently says you get 10km/l fuel consumption. However, you know from your brim to brim tests that it's somewhat lower than this. Let's say that every tank full of petrol (64.8 litres, or whatever you find it to be) allows you to travel 500km. So the Measured Consumption is 500/64.8 = 7.72 km/l Your computer is saying it's 10 ml/l so that's the Indicated Consumption. The Correction Factor (using a calculator) is: Indicated x 1000 / Measured = 10 x 1000 / 7.72 = 1295 (forget any decimals) So you replace the existing Factor with this one. Go to test 20 and you'll see the existing Factor ('ABCD'). Change D to 5 Change C to 9 Change B to 2 Change A to 1 (if necessary) by following the routine described in the instructions. If your display is in MPG, just use gallons and miles instead of litres and kilometres. Now when you use the trip computer to display your fuel consumption, it will be much nearer the truth. Note that you must allow the computer to run a good while (1000km or 500 miles or so) without resetting it to get a meaningful result. T-Cut Last edited by T-Cut; 29th December 2021 at 21:35.. Reason: Some tidying up |
![]() |
![]() |
![]() |
#2 |
Passed Away
2002 Pale Blue. Rover 75 CDTi Connoisseur auto. 170K miles Join Date: Dec 2008
Location: Near the M67.
Posts: 14,509
Thanks: 199
Thanked 585 Times in 397 Posts
|
![]() Thank you T Cut. That does help a lot..
![]() ... |
![]() |
![]() |
![]() |
#3 |
This is my second home
ZT 260 SE Twilight and 10 other 75 ZT's :O Join Date: Jan 2007
Location: Conwy NORTH WALES
Posts: 11,094
Thanks: 512
Thanked 1,116 Times in 763 Posts
|
![]() Thanks TC
(note to self to change any links to this version) TC OBD Dash diag 1.1 ![]()
__________________
[SIGPIC][/SIGPIC] Newbies do now!! 1. Plenum drains..all 3 or 4 year dependent 2. Cooling fan..All speeds functioning 3. Bonnet cable divider block |
![]() |
![]() |
![]() |
#4 | |
Avid contributor
MG ZT CDTi Join Date: Feb 2010
Location: Thaxted
Posts: 163
Thanks: 0
Thanked 0 Times in 0 Posts
|
![]() Quote:
Sorry, don't mean to muddy the water, but I did the engine coolant temp test this morning like this: Hold trip reset, key in to pos' 1, select test mode, start car - drive! Test worked OK and I got a result. Guess I'm saying, does it matter if you start the car before the test mode is selected or can it be done either way or have I just broken my car? Cheers, Simon.
__________________
[SIGPIC][/SIGPIC] ![]() ![]() http://card.mygamercard.net/gelsig/black/WE5TY+BOY.png |
|
![]() |
![]() |
![]() |
#5 | |
Doesn't do things by halves
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,387
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
|
![]() Hi T.C.,
Good move; an update was well overdue! Here's one thing I have found out. Quote:
First of all, 20.0 merely shows the current correction factor. 20.1 allows the units (first digit (4)) to be adjusted, but the display counts down not up. When a selection has been made the display will advance to 20.2. 20.2 sets the tens (second digit (3)). 20.3 sets the hundreds (2) and thousands (1) digits. There is no separate 'store' function. Other cars may differ, but that's how mine behaves. Simon.
__________________
"Whatever is rightly done, however humble, is noble." Sir Henry Royce. |
|
![]() |
![]() |
![]() |
#6 |
I really should get out more.......
MINI COOPER S Join Date: Nov 2007
Location: Tranent, East Lothian, SCOTLAND
Posts: 2,834
Thanks: 0
Thanked 0 Times in 0 Posts
|
![]() Nicely clarified TC.
![]()
__________________
.......................................Colin |
![]() |
![]() |
![]() |
#7 | |
This is my second home
ZT 260 SE Twilight and 10 other 75 ZT's :O Join Date: Jan 2007
Location: Conwy NORTH WALES
Posts: 11,094
Thanks: 512
Thanked 1,116 Times in 763 Posts
|
![]() Quote:
Engine needs to be running if you want to monitor Test No 9 : Alternator Output. 14 - 14.5 Volts No need for engine to be running: If you want to test the battery output on it's own for Volts drop with a load on it ie: With Headlamps and Blower motor on 12 Volts heading towards 11 Volts will be observed. Test no 6 No need for engine to be running for fuel level & sensor monitoring. Etc Etc. Test 7.3 Not only does the engine need to be running but the Vehicle has to be in motion for this reading. No hard & fast rules here, just think about what test you are trying to do & why.
__________________
[SIGPIC][/SIGPIC] Newbies do now!! 1. Plenum drains..all 3 or 4 year dependent 2. Cooling fan..All speeds functioning 3. Bonnet cable divider block |
|
![]() |
![]() |
![]() |
#8 |
Avid contributor
ZT CDTi + 114 Blue Join Date: Aug 2009
Location: Balloch
Posts: 206
Thanks: 0
Thanked 1 Time in 1 Post
|
![]() Found a handy site to convert litres per100km to mpg
http://www.convertworld.com/en/fuel-...er+100+km.html Hope it helps. |
![]() |
![]() |
![]() |
#9 |
Avid contributor
Rover 75 2.5 V6 Connoisseur Join Date: Feb 2010
Location: White River
Posts: 130
Thanks: 0
Thanked 0 Times in 0 Posts
|
![]() nice work! truly.
![]() could you explain 20 in layman's terms??? i have no idea what all that means ![]() my 1.8t auto gave 5 codes for which i find no info. is there a list of codes or someone i can ask? none of the error codes are "p" codes.... |
![]() |
![]() |
![]() |
#10 |
Banned
75 CDT Connoisseur SE Auto Join Date: Nov 2006
Location: Wolverhampton
Posts: 8,450
Thanks: 0
Thanked 3 Times in 3 Posts
|
![]() Spot on TC
![]() Thank you. |
![]() |
![]() |
![]() |
|
|