Disco 2 M+S & D light flashing only after ascending slopes

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Ccdelange

Ccdelange

Member
Posts
18
Location
Rotterdam
Hi everybody. My Discovery 2 Diesel automatic transmission has recently failed me multiple times while heading up (steep) hills in the pyrenees. It has operated perfect on (semi-)flat roads from Holland all to the Pyrenees, but when I go up steep slopes, after a while I get the M+S flashing, as well as D flashing on my gear selector. Also the engine light starts to shine or blink. Restarting often fixes it. Whenever I descend and stick to semi-flat surface it runs like a dream.

I've done some research and already checked the following things:

- Battery voltage (12.8v in rest)
- Cleaned battery connections
- Alternator (13.7v stationary)
- Ground connections close to the battery and ECM
- Oil level in engine and transmission box

I had it read out at a local Bosch repair shop and the throttle position sensor (TPS) showed up as the culprit on 4 different errors (didn't show the codes unfortunately). So I figured, this issue shouldn't appear when I driver on the cruise control. However, same issue on cruise control. Also, while driving flat roads and using kickdown etc. no issues with response to the throttle pedal. I know not all reading devices read transmission error codes, so currently unable to get those read. Only when I can get to a specialized shop in Barcelona (plan to go there in couple of days)

I still wanted to get up the slope. What worked better is to ascend the hill in low gears, the error didn't return. Although I did experience some minor rev drops every once in a while. A symptom often observed before the M+S & D lights flashing.

All of this keeps pointing at a faulty xyz switch. The whole automatic transmission inc. xyz switch has been replaced by a new one in the past year. All seems to work fine, except that in high gears and set to D, only D shows up in the instrument LCD, but I believe it should show which gear it is in, correct?

I do have the spare xyz switch from the previous transmission, so I could replace it. However, I'd like some of your experienced opinions to understand if this is likely the cause. Anything I could've missed?

Thanks!
 
Ccdelange said:
Hi everybody. My Discovery 2 Diesel automatic transmission has recently failed me multiple times while heading up (steep) hills in the pyrenees. It has operated perfect on (semi-)flat roads from Holland all to the Pyrenees, but when I go up steep slopes, after a while I get the M+S flashing, as well as D flashing on my gear selector. Also the engine light starts to shine or blink. Restarting often fixes it. Whenever I descend and stick to semi-flat surface it runs like a dream.

I've done some research and already checked the following things:

- Battery voltage (12.8v in rest)
- Cleaned battery connections
- Alternator (13.7v stationary)
- Ground connections close to the battery and ECM
- Oil level in engine and transmission box

I had it read out at a local Bosch repair shop and the throttle position sensor (TPS) showed up as the culprit on 4 different errors (didn't show the codes unfortunately). So I figured, this issue shouldn't appear when I driver on the cruise control. However, same issue on cruise control. Also, while driving flat roads and using kickdown etc. no issues with response to the throttle pedal. I know not all reading devices read transmission error codes, so currently unable to get those read. Only when I can get to a specialized shop in Barcelona (plan to go there in couple of days)

I still wanted to get up the slope. What worked better is to ascend the hill in low gears, the error didn't return. Although I did experience some minor rev drops every once in a while. A symptom often observed before the M+S & D lights flashing.

All of this keeps pointing at a faulty xyz switch. The whole automatic transmission inc. xyz switch has been replaced by a new one in the past year. All seems to work fine, except that in high gears and set to D, only D shows up in the instrument LCD, but I believe it should show which gear it is in, correct?

I do have the spare xyz switch from the previous transmission, so I could replace it. However, I'd like some of your experienced opinions to understand if this is likely the cause. Anything I could've missed?

Thanks!
Click to expand...
Firstly, no, if "D" is on the instrument panel that is all you will see. No matter what gear you are in. It changes on the instrument panel to reflect where you have manually moved the lever to. To be more accurate it indicates which "set" of gears, for instance "3" will stay on the panel even if you stop the car then drive off, once you have selected "3".

If the XYZ switch was replaced why do you think the old one will work better? If indeed this is the fault?
I suggest you drive it sympathetically until you can get to Barcelona and get all the codes read.
Why are you disregarding the throttle position sensor read out?
While going up the slopes but in low range it is possible your throttle was in a different position to the one when in high range. Were you testing this on the identical slope? Did you try going up the slope in "1" or "2" rather than "D"?
Did you try it in reverse?
Your gearbox may have sufficient oil but the filter may be partially blocked if it hasn't been changed recently.
A proper Land rover reader of some sort should also read the gearbox codes and point you in the right direction.
Best of luck.
And just a couple of points of etiquette.
You may wish to go to the
"Introduce yourself" thread, rather than posting directly for help.
 
Hi Stanleysteamer, Thanks for your reply. I'll make sure to introduce myself to the forum. Thanks for pointing that out. I wanted to reply earlier, but I've not been around any stable internet the last days.

My reaction:
- Good to know only the 'D' should show on the LCD, then that's working correctly.
- The reason I think the old xyz-switch might work better is because the whole automatic transmission including xyz-switch was replaced due to a mechanical faulty transmission. The previous owner recovered the xyz switch from the old one. There was no indication that was faulty, so chances are it is still good. Also gear box oil was replaced when the transmission was replaced
- I don't plan to disregard the throttle sensor read out, however, I don't believe it's the sole contributor to the problem. Because it also happened on cruise control I thought it would also be something else. I dismounted the accelerator pedal and cleaned the sensor connector.
- I tried going op in 2 and 3 but the same problem occurred in high gears. I didn't try it in reverse, as its mostly public roads. I could, however, try it on a deserted road in R and see if it occurs.
- Today I'll be in a place where they can read out the codes. Will keep you posted.

Cheers, Jasper
 
Ccdelange said:
Hi Stanleysteamer, Thanks for your reply. I'll make sure to introduce myself to the forum. Thanks for pointing that out. I wanted to reply earlier, but I've not been around any stable internet the last days.

My reaction:
- Good to know only the 'D' should show on the LCD, then that's working correctly.
- The reason I think the old xyz-switch might work better is because the whole automatic transmission including xyz-switch was replaced due to a mechanical faulty transmission. The previous owner recovered the xyz switch from the old one. There was no indication that was faulty, so chances are it is still good. Also gear box oil was replaced when the transmission was replaced
- I don't plan to disregard the throttle sensor read out, however, I don't believe it's the sole contributor to the problem. Because it also happened on cruise control I thought it would also be something else. I dismounted the accelerator pedal and cleaned the sensor connector.
- I tried going op in 2 and 3 but the same problem occurred in high gears. I didn't try it in reverse, as its mostly public roads. I could, however, try it on a deserted road in R and see if it occurs.
- Today I'll be in a place where they can read out the codes. Will keep you posted.

Cheers, Jasper
Click to expand...
Not knowing your level of expertise, may I ask if you masured the level of ATF in the gearbox with the engine running in neutral after having cycled it through all the gears?
You probably did as this is how it's supposed to be done. but you never know!
Cos if you had too little ATF it might show the same symptoms.
Also peeps more in touch with electronix than old codger me will be able to tell you if being in cruise control has any bearing. Personally I doubt it.
Somewhere on here, a while ago, someone put up pics of the throttle control showing how the resistors wore especially in places where the pedal was most frequently held, if that makes sense. Can't remember if he succeeded in mending it or just bought a new one.
Is your throttle response jerky or smooth?
 
Gearbox oil was very recently replaced with proper amounts, about 3k km’s ago. No signs of leaks or anything.

So we went to a Land Rover repair shop in Lleida yesterday and it was a pain communicating in Spanish. They had the kind of service level that you explained them the problem and they let you wait in the showroom among the newest range rovers and defender merchandise. So we couldn’t really see what was happening or talk to the mechanic. Pretty annoying.

bottom line, they did a read out, however no report or code #’s while I specifically asked for it. Diagnose by the mechanic from the read out was a faulty turbo. No signs of TPS anymore. The diagnose seems right and feels in line with behaviour of the car.

Lleida is not a pretty city and we wanted to go to Barca, so we discussed with them and decided to bring the car to Barca on secondary roads keeping it in low revs and trying not to engage the turbo here. We once pushed too hard and had the same issue again. But after giving the car a rest and trying again we drove the final 150 km without problems and plan to go to a shop today or Monday. So I hope the turbo replacement will fix our issue.

I’m going to ask if I can see the read out in the next shop we visit so I can take note of any specific codes that show up.
Thanks for the help so far and keep you posted!
 
Update

Today I went to the Land Rover mechanic:

3 faults:
1. P1884 - 18 --> Throttle position invalid. Substitute throttle angle of 50% adopted. No kickdown. Operates in economy modes only. On On. Frequency: 1. I suspect it is an old one. I've cleaned the connections.
2. P1884 - 33 --> Engine torque invalid. Substitute engine torque of derived from other inputs. May affect shift quality. On Off. Frequency: 283. This must be the culprit.
3. Turbo fault (unspecified code). This was what the previous mechanic also found and seems wear out. Due to both mechanics the turbo failure is unrelated. We can have it fixed in the area. This probably explains why we experience power loss at certain rev's.

However, what strikes me is that the P1884 - 33 error occurs often, but we've experience only a fraction of those errors the engine being killed by the ECU.

Will it only kill the engine after the errors surpasses a certain threshold?

By searching for this engine code I came across this topic, which feels strikingly familiar to my issue. Hopefully the topic starter will reply to my question what solved the issue.

Next steps I'm going to take based on further searches:
- Cleaning out the red connector to the ECU
- Measuring data wires resistances

Still uncertain if the xyz-switch replacement could help. Also did the windscreen wiper + reverse test, that worked fine.

Any other ideas to what triggers the P1884 - 33 particularly at (steep) ascends? Could it be related to the failing turbo anyway? Thanks
 
Update:
Looks like turbo is working fine. Finally found a mechanic who speaks english, seems to have some more advanced diagnosis tools (Autel Maxisys) and has time to have a look at the car.
The problem has increased. Very unstable revving also at stationary speeds currently.

When applying the diagnosis computer three things struck me:
- it couldn't automatically read the VIN
- High / low gear switch showed reversed values
- Wrong indication of automatic transmission selector switch (xyz), completely off

About the xyz, when in operation it always works fine, correct indication of the red leds next to the selector, and correct indication of setting in the dashboard LCD. Could it still be the xyz switch that is faulty? Or do I need to look at a wiring problem, potentially related to the BCU, since also the VIN data could not be read?

I'm about to go into fault finding mode with my favourite Spanish mechanic right now.

@sierrafery Maybe you have a take on this issue?
 
Have you checked the wiring loom on top of the gearbox/transfer box?
There is a famous P-clip there that has a tendency to lead to wires chafing inside the insulation.
This has been documented on here before. With pictures.
This can lead to intemittent shorting out or misconnections.
and this can lead to similar behaviour to that you describe.
A simple thing to check and an easy thing to fix.
 
Ccdelange said:
Looks like the wires are bad around the p clip. How to best reach the wires to require or reinsulate? I found this there’s with pictures, no other one: https://www.landyzone.co.uk/land-rover/auto-gearbox-loom-removal.349500/
Click to expand...
Well first of all, congratulations on finding at least something you can see to! And yes that is more or less the thread i meant.
You might have to ask @Henry_b the best way of taking that part of the loom off. Or anyone else who has done it.
Secondly I have no idea how to reach it, but I'd start for looking for the connectors, then taking them apart, then taking off the P-clip.
Once you've got it off then opening up the insulation, examining all the wires very carefully, soldering back any broken ones then insulating each wire individually before putting insulation around the whole mini-loom is how I would approach it.
And to be totally honest, I'd find getting the clipped connections separated the hardest part of that as I find there are a variety of connectors and separating them isn't always obvious.
 
Okay, yesterday we've stranded along the way and needed to be towed as the problem persisted and got worse. On Monday we can get a mechanic to look at it. However, I've written an extensive update on the events and diagnoses of the past 2 weeks, to translate to Spanish and inform the mechanic. Here it is. Any thoughts are very much appreciated, thanks!:

Friday we stranded alongside the road with no power in the land rover. We're experiencing the issue already for 2 weeks, and it became bigger and bigger. I'll break down to you:
  • Our experiences and events
  • What we have done to the car after the issue occurred
  • Maintenance record of the car in the past year.
  • Suggestions I find on experts online forums about solutions
Issue summary:
When the car is on working temperatures and we ask power from it (i.e climbing steep hills, kickdown), all of a sudden the engine stalls, M+S lights blink on the dashboard, D lights next to gear selector switch start blinking and D in the dashboard LCD blinks, suggesting automatic transmission fault.

Over two weeks, while we tried to fix the issue on several places, the problem got worse and we started experiencing drops in engine revolutions before above engine stall occurred.
It never occured so far when the car is cold, still up till now.

Faults / Diagnosis chain of events:
  • We had low diesel level and parked the car on a steep slope. When trying to start the car again it did not start, potentially because of fuel not entering the inlet of the fuel pump in the gas tank. When we rolled the car back to a level surface, the car started up again.
  • We entered the Pyrenees heading to Andorra. After some steep climbing before the Spanish border, we experienced a sudden engine stall. The green M+S lights on the dashboard were blinking and the car did not allow us to give power, I don't know if the D on the transmission selector switch and/or the LCD was blinking back then. After shutting the car down and restarting, no issue anymore. This happened 2 times more on that day. After the 3rd time, we also experienced drops in engine revolutions after the reboot of the car.
Monday August 9th:
  • Replaced the diesel filter, because it sounded like it could be the issue. Drove up the hills again, same issue.
  • Other repair shop (Bosch car service) read out the computer codes, he diagnosed the throttle position sensor (TPS). But no indication of gearbox errors (I think his tool was unable to read). He would try to get a replacement TPS, but could not get it, no answer at his suppliers.
Tuesday August 10th:
  • Drove uphill again. Very difficult to climb the hill. Many errors. Tried to run the car in '3' or '2' instead of 'D', but issue occurred still. When switching to low gear, only once the issue after a lot of time.
  • I took apart the gas pedal and sensor and cleaned the connections
Thursday August 12th:
  • Drove to Graus, mainly downhill. When staying below 2200 engine revolutions we were sure to not have the error, so no issue that day
Friday August 13th:
  • Drove to Lleida, to official Land Rover mechanic, he diagnosed the turbo was faulty + that there was some oil residu in the ECU (onboard computer connections), We’ve cleaned that. We wanted to spend time in Barcelona so decided to drive to Barca.
  • On the highway we stayed below 2200 rpm but experienced the issue once again. Presumably because the Lleida mechanic had really pushed the car right before we took it.
Monday August 16th:
  • Diagnosis at official Land Rover dealer was faulty turbo, needs replacement, and faulty gearbox, probably mechanic.
  • I found that hard to believe because the shifting occurred correctly and also boost occurred correctly. Also no faults on overboost in the car computer
  • The mechanic explained these cars were never sold with automatic transmission in Spain
  • He pointed us to turbo3 in st. Boi de Llobegrat for checking the turbo.
  • Details on the faults, see the report from the mechanic (in Spanish)
    • 238x: CAN Message MD_IND invalid (flag F_TL_MES) --> Engine torque invalid. Substitute engine torque of derived from other inputs. May affect shift quality.
    • 1x: CAN message WFPDK (DKI) invalid (FFh) --> Throttle position invalid. Substitute throttle angle of 50% adopted. No kickdown. Operates in economy modes only. On On
    • 1x: Faulty turbo
Tuesday August 17th:
  • Turbo3 checked the turbo, no issue with the turbo itself, wastegate actuator or engine inlet pressure (after turbo 1.1 bar)
  • They suspect a broken electronic turbo valve.
Wednesday August 18th:
  • Collected a replacement electric turbo valve from a spare parts shop and mounted it myself, mechanics were very busy. Replaced the 3 hoses. Issue only got worse
  • Also drove some time with disconnected Mass Airflow Sensor, because faulty readings of that sensor could make the engine run bad.
  • Visited a mechanic and asked about the turbo. He said the turbo was faulty. So we decided to visit Turbo3 again.
Thursday August 19th:
  • Drove to Turbo3 on a secondary road along the coast with a lot of ascending, a lot of issues on the road there, had to stop several times and restart the car again. They checked the turbo, assured us no issues. He demonstrated and it worked fine. The signal from the computer made the engine run poor.
  • We experienced the revolutions drops also on lower revolutions (1800-2000rpm)
  • Read out from local shop. Remarks from live data:
    • Vehicle identification number could not be identified automatically from connection
    • High/low gearing switch indication was reversed, so when switch was in low gearing, computer read high gearing and vice versa
    • All switch positions could not be read properly, sequence of PRND123 was wrong on the read out. However on the dashboard LCD and on the red switch lights, the position is always properly indicated. The mechanic suggested this might be a wrong read out by his diagnostic computer.
Friday August 20th:
  • He attached the Autel Maxisys diagnostic computer and read the following codes on the engine:
    • Driver demand 1 out of range fault logged (throttle position sensor)
    • Driver demand 2 out of range fault logged (throttle position sensor)
    • Fault detected with driver demand logged
    • Engine Speed outside bounds for cruise (where fitted) Active
    • Vehicle Speed outside bounds for cruise (where fitted) Active
  • And the following codes on the gearbox
    • CAN Message MD_IND invalid (flag F_TL_MES) --> Engine torque invalid. Substitute engine torque of derived from other inputs. May affect shift quality.
    • CAN message WFPDK (DKI) invalid (FFh) --> Throttle position invalid. Substitute throttle angle of 50% adopted. No kickdown. Operates in economy modes only. On On.
  • Cleaned connections to XYZ switch, no result
  • Checked wires on XYZ switch wiring visually, seemed okay even though the insulation hose around the wires seemed a bit bad.
  • Mechanic suspected failure with fuel injectors, so took the cylinder head off and cleaned all electric connections to fuel injectors, and reput the cylinder head
  • The problem remained. We decided to continue to Sala, first without the air-conditioning on (could be leaking water on xyz/ cables)but on the road we started to get the issue again, and lost complete power, also after waiting some time. Engine could be started and ran properly, however when switching to R or D immediately the engine light and M+S started flashing. And the power on the gas pedal failed. Grua had to come and take us away.
  • currently awaiting mechanic to look on Monday

Summary of relevant maintenance
  • December 2020:
    • Replaced fuel filter + diesel cleaner
    • Replaced automatic transmission, because of mechanical fault. Gear selector switch (Xyz) was recovered and still working properly. I have that with the car
    • transfer box oil change
    • differential oil change front + rear
    • Replaced fuel pump
  • April 2021: Automatic transmission sieve replaced + oil change
  • August 9, 2021: Replaced fuel filter
  • August 10, 2021: Cleaned throttle position sensor contacts
  • August 18, 2021: Replaced electric turbo valve + 3 connecting hoses
  • August 19, 2021: Turbo validated to work correctly with Turbo3
  • August 20, 2021:
    • Cleaned gear selector (xyz) switch contacts
    • Checked wiring to gear selector switch above transfer box and gearbox
    • Cleaned fuel injector contacts under cylinder head

Suggestions from various land rover forums:
  • XYZ switch faulty, could still be the case, since the readings on the diagnostic computer were faulty, but when car is cold, perfect function. Likely to occur due to air conditioning condensate water outlet right above the switch.
  • Wiring to xyz switch faulty, common issue given how the wires are connected to a p-clamp on top of the transfer box
  • Throttle position sensor faulty
  • Low voltages causing bad signals:
    • Battery has nominal voltage of 12.7v --> cleaned both + and - connections
    • Alternator runs at 13.7v on idle speed
    • Bad grounding to sensors or switches, did not check to rule out
    • Low supply voltages to switches
      • Gear selector (xyz) switch
      • Manifold Absolute Pressure
      • Ambient air pressure sensor
      • Mass air flow sensor
  • Bad wiring, particularly because the fault is intermittent and happening at normal temperatures, but not when car is still relatively cold
  • Suggestion from the mechanic in Calaf, he thinks it has to do with engine fuel injectors, not with computer signal issues.
What i want the mechanic to check:

What I like to do for sure:
  • Check proper gear selector switch (XYZ) working
    • Read out live signals from switch, if incorrect -->
    • Replace xyz switch
    • Read out signal again, if signals good, test run the car
  • Measure supply voltages to sensors
  • Check engine fuel supply (fuel pump, fuel injectors)
What I think are proper follow up actions:
  • Measure proper grounding of sensors and switches, if faulty, check grounding
  • Measure proper read out voltages of sensors, if faulty replace
  • Replace TPS sensor, I've ordered one already

Hopefully this extensive description will help others when we manage to fix the issue.
 
According to the fault codes seems like TPS input issue which can be the sensor or it's circuit, do a simple test though cos i've seen driver demand fault codes triggered by low fuel pressure: https://www.landyzone.co.uk/land-rover/check-td5-fuel-pump-hp.358086/ and this would confirm the invalid torque code too
For this kind of intermitent fault live data readings are necessary to see all sensor inputs
 
Fuse F10 measures 20.6 mV. When engine runs stationary. Not the 23 as stated but certainly not the 10 mV. So I guess HP is still good? Or is this voltage worrying?

im not sure I can get the right TPS from Spain, in contact with a store. Any suggestions where I could order a TPS from the UK? Attached a picture from my TPS: 09017 >PBT-(GF20+GB20)<
 

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The 20.6mV is still OK. Contact this guy
Discovery 2 Parts
Quality Used and New Parts & Accessories
Call Paul on
01206 211623 - office
07828 278465
07760 955966
07840 428888
he shoud have a tested working one
 
Thanks a bunch for the suggestions.

I just ran it around 2200 rpm for 1 minute in P and got the problem again after no running for 15 hrs. Can I assume that it is not related to any wiring or xyz switch of the transmission? It at least eliminates the load / temperature precondition for the fault to occur.
 
Will watch the read out tomorrow, we kept getting the p1884-33 for this failure in multiple read outs. I expect to see it tomorrow again.
 
Ccdelange said:
Will watch the read out tomorrow, we kept getting the p1884-33 for this failure in multiple read outs. I expect to see it tomorrow again.
Click to expand...
Hi, sorry to hear of all your woes but just on the High/Low readings being the wrong way round on diagnostic tools, this is perfectly normal & not a fault as I think Sierrafery will confirm. Hope you get this sorted soon best of luck.
 
Just noticed something new, I have my main battery connected to domestic batteries (fridge) through a relay so it charges from the alternator once the voltage an the main battery is above ~13.6.

wired like thisit’s the 120 version: https://www.victronenergy.com/upload/documents/Datasheet-Cyrix-ct-120A-230A-EN.pdf

Now I noticed yesterday that there the relay was open (putting both batteries parallel) but the voltage on the domestic batteries (12.04) was not near to the 13.8 as measured on the main battery. So the connection to ground from these batteries is potentially corroded or bad. So I thought this might impact grounds of other electrical components as well.

Later today I have time to disconnect the domestic batteries and measure supply voltage vs various grounds over sensor connectors, starting with MAF / AAP / MAP / TPS

Does it make sense that this circuit could impact ground corrosion on other electrical components?
 
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