Technical help! Many dash lights, many messages, U1706 error code.

[Jamie KC]

The wife's Panda is a 2014 1.3 MJ 4x4, and on a couple of occasions recently has been slightly problematic for her.

A week or so ago the dashboard went all christmas tree on her, and the car felt slightly hesitant. When she tried to turn it off the dash and radio turned off as normal, but there was a delay between turning the key and the engine stopping, perhaps a second or so. I had a look at the car in the eve, no stored codes, started and ran as normal.

The warning symbol has been on constantly, but I had attributed this to a faulty DRL plug and and bulb holder causing a check DRL message.

Problems today:
- The dash was all lit up again
- The external temperature display wasn't working
- The speedo needle was sitting at zero when driving
- Multiple messages were displayed.
- Have power steering checked, see handbook
- Check engine
- Check DRL
- Start/Stop unavailable

When turning off the first time there was a delay again, when arriving at home and trying to turn off it kept running, even with the key removed! So stalled it to turn off.

Did a code read via an app and OBD, get U1706 as the only code.

I'm not gonna get to look at it until Thursday AM. The first thing I'll look at is battery connections, voltage, earth cables incl earth points under tray.

What else should I be going for with the sort of symptoms described please?

 

[Panda IIs]

Poor battery volts come to mind immediately or perhaps bad earth strap (engine to body) both not unusual! How old is the battery? Also be aware that not all "generic" OBII apps can get the finer detail from these cars MES is the preferred tool I believe.

 

[Jamie KC]

Thanks. I’ll be checking earth straps on Thursday AM, and hoping it’s as simple as that!

Battery is 3-4 months old. Voltage holding a lot steadier than the previous battery, although it still started with the old one it struggled a little on very cold days and I felt it was going to be unreliable through the winter.

 

[Panda IIs]

Thanks. I’ll be checking earth straps on Thursday AM, and hoping it’s as simple as that!

Battery is 3-4 months old. Voltage holding a lot steadier than the previous battery, although it still started with the old one it struggled a little on very cold days and I felt it was going to be unreliable through the winter.

Alternator charging ok? It was a Stop/start battery (the new one)??

 

[Jamie KC]

Alternator charging ok? It was a Stop/start battery (the new one)??

Twas a Yuasa EFB027 which is a stop/start and has a good capacity.

Charge rate is typically 14.6v at idle, slightly over that under throttle.

Checking out electrical shizzle tomoz may now have to wait with the look of the weather that’s developing; I’m on a driveway with no shelter on the back of an exposed Cumbrian hillside, gonna be windy and wet which isn’t ideal for diagnosing those types of issues! Grrr

 

[Herts Hillhopper]

I’m sorry to say this sounds like an ECU issue… but I doubt it’s the actual unit, more likely a wiring fault in a loom that connects to it. Worth unplugging and reconnecting the two big plugs on top of it - checking for any corrosion or water there. And searching for any chafed wires around under the bonnet (but that’s a bit needle and haystack). Also look in the main under bonnet fuse box at the main power relays.

 

[Jamie KC]

Had to head out in it this morn before I can do any work on it, ELD is constantly engaged! Could feel the rear diff winding up and clicking when parking. Can also feel it at low speed slight weave too, no clicking then but can feel the slight hesitation it gives to smooth rolling/manoeuvring.

Pressing the button does nowt, am guessing there is a fuse to pull to disable it? Unless it is a system that requires power to disable as opposed to enable.

Had assumed light was on as every other light is on and it was just completing a clean sweep of things that are upset/unavailable…

 

[Herts Hillhopper]

There is a fuse for the 4x4 system - ill
look up which one as I think it’s in an odd place.

If all else fails you could unplug the connection to the ELD solenoid which on the left side of the diff, near the front of the housing.

The dash ELD light should not be on, unless the ELD has actually engaged (which normally only happens for a couple of seconds) - but I appreciate your car has turned all sorts of lights on…

 

[Herts Hillhopper]

I knew I had seen this (below) somewhere but wanted to find it before posting this reply, to be sure I'd remembered it right

A lot of the issues you are seeing are related to the ABS system ECU. And the cause may well turn out to be the brake light switch! This switch (which is in the passenger-side footwell of a RHD Panda) has two sets on contacts. One that turns the brake lights on when the pedal is pressed, and another that closes the contacts when the switch is fully raised. It's this latter bit that fails. The ABS and emergency brake assist use these two sets of contacts (along with the switch on the clutch pedal) to decide if the brake pedal has been pressed extra hard and the clutch as the same time -- ie an emergency stop.

Here's the line from the earlier post. I won't link to the thread as the rest of it was unrelated... but the post was from Panda II's

"...a spate of warning light issues all related (if distant cousins) to the ABS system, these included hill-holder unavailable, ESC, ABS and 4WD warning lights (the message seems to be Don't Panic) all of this nonsense was sorted by replacing the brake light switch... "

Others too have had all sorts of odd errors (including airbag warnings etc) cured simply by replacing the brake switch.

I think the 'U' errors codes are ABS system too?

 

[Jamie KC]

I knew I had seen this (below) somewhere but wanted to find it before posting this reply, to be sure I'd remembered it right

A lot of the issues you are seeing are related to the ABS system ECU. And the cause may well turn out to be the brake light switch! This switch (which is in the passenger-side footwell of a RHD Panda) has two sets on contacts. One that turns the brake lights on when the pedal is pressed, and another that closes the contacts when the switch is fully raised. It's this latter bit that fails. The ABS and emergency brake assist use these two sets of contacts (along with the switch on the clutch pedal) to decide if the brake pedal has been pressed extra hard and the clutch as the same time -- ie an emergency stop.

Here's the line from the earlier post. I won't link to the thread as the rest of it was unrelated... but the post was from Panda II's

"...a spate of warning light issues all related (if distant cousins) to the ABS system, these included hill-holder unavailable, ESC, ABS and 4WD warning lights (the message seems to be Don't Panic) all of this nonsense was sorted by replacing the brake light switch... "

Others too have had all sorts of odd errors (including airbag warnings etc) cured simply by replacing the brake switch.

I think the 'U' errors codes are ABS system too?

Really appreciate the effort put into recalling and finding that information. I’ll try and get a look at it soon, with a combination of appointments and meetings running over today, kids to collect and feed, some uncooperative weather and all other life things I didn’t get near it in the end today.

Did read codes again whilst delivering a child to Cadets, had P0555 displayed whilst driving. Didn’t see this when taking a stationary reading yesterday.

Will driving with ELD constantly engaged be a problem? There are no days off in my immediate future, and no opportunities to get under the car before school runs and work tomorrow.

 

[Jamie KC]

Brake switch changed as could get part on way home and tackle on the kerb. Cleared codes forehand and disconnected earth strap for 10 mins. Sadly, no fix! Grrr

Was hoping it would’ve been that easy!

 

[Herts Hillhopper]

Really appreciate the effort put into recalling and finding that information. I’ll try and get a look at it soon, with a combination of appointments and meetings running over today, kids to collect and feed, some uncooperative weather and all other life things I didn’t get near it in the end today.

Did read codes again whilst delivering a child to Cadets, had P0555 displayed whilst driving. Didn’t see this when taking a stationary reading yesterday.

Will driving with ELD constantly engaged be a problem? There are no days off in my immediate future, and no opportunities to get under the car before school runs and work tomorrow.

it won't do the 4x4 system much good if its 'stuck' in forced 4x4. I'll look ups that fuse (I forgot!)

 

[Herts Hillhopper]

The fuse is number 23 in the box under bonnet -- a 7.5amp fuse highlighted in bold here. This *only* covers the rear diff engagement so should be fine to remove and still drive (the same location is used for 2WD with the Dualogic gearbox, but that won't apply here)

 

[Herts Hillhopper]

Brake switch changed as could get part on way home and tackle on the kerb. Cleared codes forehand and disconnected earth strap for 10 mins. Sadly, no fix! Grrr

Was hoping it would’ve been that easy!

this a shame...

 

[Herts Hillhopper]

OK, not the brake switch... but also worth a check is the condition of the wiring that is under each front seat for the 'occupancy detectors' as these also affect the airbag system. The wires will have yellow sleeves or yellow connectors (there may be others for seat heating too). These can get damaged by things stowed under the seat or caught in the runners. Again, somewhere, someone had random lights and errors caused by this. They run off into the plastic 'boxes' on the floor just in front of the seats (the left hand one also contains the ECU that controls the rear diff and ELD)

 

[Jamie KC]

OK, not the brake switch... but also worth a check is the condition of the wiring that is under each front seat for the 'occupancy detectors' as these also affect the airbag system. The wires will have yellow sleeves or yellow connectors (there may be others for seat heating too). These can get damaged by things stowed under the seat or caught in the runners. Again, somewhere, someone had random lights and errors caused by this. They run off into the plastic 'boxes' on the floor just in front of the seats (the left hand one also contains the ECU that controls the rear diff and ELD)

Thank you. Will check this out when I get a mo.

Bizarrely the EM light stayed off for 20 miles after the code reset, even though U1706 was still being displayed. It only came back on when P0555 popped up again.

I may have to invest in an MES package to get better diagnostic info me thinks…

 

[Jamie KC]

The fuse is number 23 in the box under bonnet -- a 7.5amp fuse highlighted in bold here. This *only* covers the rear diff engagement so should be fine to remove and still drive (the same location is used for 2WD with the Dualogic gearbox, but that won't apply here)
View attachment 482880

Pulling this fuse on Monday helped a lot. The car was constantly feeling like a coiled spring, as if it was offering resistance to every movement, and smashing its way through diesel. Fuse out and it’s driving normally again, no nasty noises on turning and rolling as it ought to. Thanks for the location!

 

[Jamie KC]

Today’s investigation was limited in time available, but I focused on the ignition switch due to the not turning off.

I had already found that you could turn the key back to the off position and remove it, and the car would keep running, although the dashboard was off. But today I discovered that if you turned the key slightly back (but not fully) towards the ON or MAR position, then the engine would turn off.

Next step, using a probe to investigate the function of the wires in the ignition switch, which revealed:
Green/Red wire - constant live
Brown wire - temp live to starter solenoid when starting position engaged
Orange wire - negative when ignition off, positive when ignition on
Blue wire - as orange, negative when ignition off, positive when ignition on
Grey wire - as orange, negative when ignition off, positive when ignition on

Pic of ignition switch wiring for reference.

Now, when probing the orange wire, and clicking the switch to the off position, the brightness displayed on the probe was lesser than the brightness on the other two wires. And when you turn the switch back slightly towards the ON / MAR position, the light reaches full brightness and the engine turns off! First video attached below is to demonstrate this, shows key out and engine running, then key back in and a slight turn to cut the engine. Video of switch operation and LED after that without key. Compressed videos, hopefully viewable.

So I wonder if this is a coincidental switch issue, or perhaps a faulty switch connection could be providing voltage drop or high resistance and could be the entire problem?

I’ll have to look into a replacement switch a little further, ePer seems to suggest that the switch is not available as a spare part on its own, but fingers crossed aftermarket may be…

 

[Herts Hillhopper]

There is a bit of trickery in the ECU that keeps a few bits in for a short time after the key is turned off - at least there is in the diesel versions. When turned off you can still hear the fuel pump run for a few seconds, and the EGR valve opens and closes which is supposed to help clean it. So you may find there is a live feed with the key off - just to complicate any investigation

 

[Jamie KC]

Update - I've found a little time in moments here and there to try a couple of things on the Panda now.

So far I've tried, all with no difference;
- Changed brake light switch.
- Charged battery (new Yuasa one 4 months ago).
- Changed ignition barrel and switch as needing slightly odd positioning of key to kill the ignition.
- Cleaned all earths around and below battery tray (despite charging voltage test only showing 0.1v difference from batt +/batt - and batt +/engine block - which really means doesn't appear to be an earth issue).
- Changed main earth lead from body to box/engine out of paranoia (no change in charging voltage test).
- Inspected any fuses associated with ABS, BCM, power steer systems etc as they are indicated in U1706 code on other/older Fiat/Alfa vehicles.
- Inspected connections under seats/behind plastic covers.
- Pulled the fuse to engage the ELD as she wasn't driving well.

Quick reminder of symptoms to save re-reading;
- Immediate U1706 code on start up even after clearing code (doesn't trigger engine management light).
- P0555 code pops up on most journeys after clearing and triggers EM light (happened both before and after removing ELD fuse).
- Christmas tree dashboard (EM, ABS, ESC, steering light, handbrake/fluid level light, the triangle).
- ELD was constantly engaged until fuse pulled.
- Speedo not working, odometer not increasing, external temp display blank.

Suggestions please of what/where to look next?
- Where is the BCM on these? And where does the loom for it run?
- @Herts Hillhopper you mentioned the ABS ECU too, but more likely associated wiring. Where to find ECU and loom path?
- What else could I be looking at?
- Will MultiECUScan be likely to give more detailed insight?


Many thanks, Jamie