Technical 500X 4x4 1.4 MultiAir - AT9 Gearbox error P1DB7 ?

[FCA]

Recently (3 months ago) bought a very low mileage 17k, nearly 5 years old 500X 4x4 1.4 MultiAir Cross Plus. The car has been hardly driven the last 2 years before I acquired it. It has done 3000 miles in the 3rd and 500 miles in the 4th year. It was regularly and fully serviced at a FIAT dealership. Shortly after the purchase, there were lots of error messages related to almost anything and everything, starting with stop & go, incorrect ambient temp., line assistance, blind spot, emergency break, hand break, infotainment completely unavailable, partially broken DAB, rain sensor, injection failure, etc. but the car was driving normally despite all those warnings. Finally, getting a new ambient temp. sensor, antenna base for the DAB and a new battery resolved all those issues apart from an intermittent one, "Transmission failure" - "Check engine" - "Driver mode unavailable", read error code P1DB7. It comes and goes with no impact on driving so far. What's strange, the car is very fast, accelerates in normal mode very very well, in sport it's quite difficult to handle, on wet when pushed it losses grip in "sport" on all 4 when accelerating in lower gears. Also the max speed is impressive and it accelerates well from e.g. 90 onwards on an "Autobahn" up to 110-120 up hill and almost to the end of the clock on a straight, the only downside, low mpg when driven fast. I've done already 2.5k miles, 0 oil consumption, no other issues. The error code only occurs when the engine/gearbox is warm and after driven at a pace or under load when accelerating, with no impact on the car's driveability. "Transmission failure" disappears instantly after an engine restart and "check engine" clears completely after a couple of stops. My local FIAT garage diagnostic resulted in: "internal gearbox failure" and a new one is required??? Any ideas?

 

[s130]

The official info for this error code is:

500X 1.4 Turbo MultiAir Torque Converter Clutch Performance P1DB7-00

 

[FCA]

Many thanks s130 for an important piece of information. A Happy new Year 2022.
My car is going strong after more than 4k miles since purchase. The mpg has improved, despite the weather getting colder. The car is far more responsive overall, also drives better and more economical on warm days in particular. Same with tyres, warm days fine, cold mornings awful. I'm on the original set of Goodyear F1 Asymmetric 2, although the front is now down to 2 mm across, looking to replace them very soon - any suggestions? Myself looking at Pirelli P Zero PZ4 currently as the best option.
So far not much luck with getting a permanent fix for that rare/intermittent gearbox error P1DB7. Went to Bristol Transmissions and initially they couldn't replicate the fault, then later I was able to do it for them. Unfortunately, their only solution is to overhaul/replace the entire box, including the torque converter, for the price of £6700 !!!, more than what I got quoted by a FIAT dealer.
My local closest authorised FIAT garage in Chippenham checked the gearbox oil level only, which was fine, but unfortunately wasn't able or willing to check the wiring and solenoid valve unit according to the info you've provided.
Nor sure what to do next.

 

[s130]

My local closest authorised FIAT garage in Chippenham checked the gearbox oil level only, which was fine, but unfortunately wasn't able or willing to check the wiring and solenoid valve unit according to the info you've provided.
Nor sure what to do next.

Rather odd that the dealer is not willing to check as per the fiat diagnostic information. Of course there is never any guarantee that the Fiat diagnostics are always correct but it is a starting point.

Sadly many younger technicians (no offence meant) just don't have the old school "nose and experience" to try and reason out things from scratch. "The computer says ......" often rules and is sometimes an excuse / coverup by the "garage" in the garage's (again not pointing at any technician) ability or willingness to get further involved.

Another compounding fact is that most garages use Mfg. / Auto Data / equivalent to quote a price. So Mfg. / Auto Data list times for just about every job from routine servicing to brake, clutch, gearbox, engine changes etc.. That said I know many garages bitch that a quoted time for a job is very optimistic and it take them longer but they have to/do charge at the listed rate. This partly accounts for their higher labour rates over independents. So when a odd and potentially complex and open ended job comes in they are often reluctant to get involved as it screws up their job schedules for other customers. This is where a time tolerant customer and decent independent and trusted garage can work out better. e.g. you book in for a day on the expectation that you may not get your vehicle back that day/week. They have a full 8 hours in their schedule for the work but if that is not enough then basically they work on the car between other jobs.

 

[PANJGA884]

Recently (3 months ago) bought a very low mileage 17k, nearly 5 years old 500X 4x4 1.4 MultiAir Cross Plus. The car has been hardly driven the last 2 years before I acquired it. It has done 3000 miles in the 3rd and 500 miles in the 4th year. It was regularly and fully serviced at a FIAT dealership. Shortly after the purchase, there were lots of error messages related to almost anything and everything, starting with stop & go, incorrect ambient temp., line assistance, blind spot, emergency break, hand break, infotainment completely unavailable, partially broken DAB, rain sensor, injection failure, etc. but the car was driving normally despite all those warnings. Finally, getting a new ambient temp. sensor, antenna base for the DAB and a new battery resolved all those issues apart from an intermittent one, "Transmission failure" - "Check engine" - "Driver mode unavailable", read error code P1DB7. It comes and goes with no impact on driving so far. What's strange, the car is very fast, accelerates in normal mode very very well, in sport it's quite difficult to handle, on wet when pushed it losses grip in "sport" on all 4 when accelerating in lower gears. Also the max speed is impressive and it accelerates well from e.g. 90 onwards on an "Autobahn" up to 110-120 up hill and almost to the end of the clock on a straight, the only downside, low mpg when driven fast. I've done already 2.5k miles, 0 oil consumption, no other issues. The error code only occurs when the engine/gearbox is warm and after driven at a pace or under load when accelerating, with no impact on the car's driveability. "Transmission failure" disappears instantly after an engine restart and "check engine" clears completely after a couple of stops. My local FIAT garage diagnostic resulted in: "internal gearbox failure" and a new one is required??? Any ideas?

I have had similar issues with my 2016 Fiat 500x since this October. Bought used w/ approx. 35k on it in 2019. Over the past two years have had intermittent random warning lights come on/off - most notably the forward collision warning system turning itself off randomly. Lots of blown running & parking lights. Always mentioned these at my service appointments but never any luck figuring out where the issue stemmed from. I always suspected something electrical.

Car was at approx. 65k miles when recently was driving for about 2 hrs on a warm, humid GA day at highway speeds (80 mph). Drove through some torrential downpours too. After I was out of the rain, I went to pass a vehicle and as soon as I hit the accelerator, I got the "Service trans", "check engine" lights. Car was driving fine otherwise. Perhaps a slight chemical burning smell I noticed but otherwise fine. Took it to a dealer nearby who scanned it and gave me that same stored error. Drove the car 2 hrs home. Errors cleared overnight but still took it in to my local mechanic. They couldn't replicate error/code so sent me on my way. Errors came back a few days later while driving normal speeds. They recommended just doing a fluid change which I agreed to. Drove fine for about a week.

Then as I was driving north to visit family (about 700 miles away), the lights returned. Took it to Fiat this time who diagnosed it as a torque converter issue and recommended replacing that and the valve body. Took a full month for them to do the work. Most notably when I got the paperwork back there was indication of metal in the transmission which they had not mentioned to me in my phone calls with them. I asked them why with a sealed, filterless transmission they felt only replacing these parts was a good fix. Surely if there was metal in the trans, it had been circulating through the entire system and caused more extensive damage to all the components. It was quite the frustrating ordeal having that convo with them. They didn't see it as an issue.

Drove the car off the lot and immediately heard grinding and had gear changing issues (between 1-2 and again between 6-7). Took it back to them and they said the TCM got wiped somehow and needed to be reprogrammed. Did that and car worked fine for about a day. However, the lights did return. Got pretty pissed this time with them and got FCA Cares involved.

Returned car to same dealer who stated the clutch had burned out (surprise surprise) and recommended an entire trans replacement. I just got the car back yesterday. Has been over 2 months back and forth in their shop. FCA Cares couldn't care less. All they did was provide some assistance with checking in on the work the dealer was doing and reporting back to me. They were otherwise useless and callous.

Thank God I had a service contract on the vehicle otherwise I would have been looking at close to 10k in total repairs. Nevermind all the lost time and money on traveling back and forth because I thought it was fixed, renting/borrowing other vehicles, etc. I fully intend on trading this awful vehicle in as soon as I can and letting Fiat have it wherever I can.

Wondering if anyone else has had their trans replaced and it solved any issues? Again, I have always suspected the issue was electrical. I doubt the trans is the actual issue. Perhaps a result of something larger - but not the primary issue itself. Fiat doesn't seem to care to figure it out.

 

[FCA]

I have had similar issues with my 2016 Fiat 500x since this October. Bought used w/ approx. 35k on it in 2019. Over the past two years have had intermittent random warning lights come on/off - most notably the forward collision warning system turning itself off randomly. Lots of blown running & parking lights. Always mentioned these at my service appointments but never any luck figuring out where the issue stemmed from. I always suspected something electrical.

Car was at approx. 65k miles when recently was driving for about 2 hrs on a warm, humid GA day at highway speeds (80 mph). Drove through some torrential downpours too. After I was out of the rain, I went to pass a vehicle and as soon as I hit the accelerator, I got the "Service trans", "check engine" lights. Car was driving fine otherwise. Perhaps a slight chemical burning smell I noticed but otherwise fine. Took it to a dealer nearby who scanned it and gave me that same stored error. Drove the car 2 hrs home. Errors cleared overnight but still took it in to my local mechanic. They couldn't replicate error/code so sent me on my way. Errors came back a few days later while driving normal speeds. They recommended just doing a fluid change which I agreed to. Drove fine for about a week.

Then as I was driving north to visit family (about 700 miles away), the lights returned. Took it to Fiat this time who diagnosed it as a torque converter issue and recommended replacing that and the valve body. Took a full month for them to do the work. Most notably when I got the paperwork back there was indication of metal in the transmission which they had not mentioned to me in my phone calls with them. I asked them why with a sealed, filterless transmission they felt only replacing these parts was a good fix. Surely if there was metal in the trans, it had been circulating through the entire system and caused more extensive damage to all the components. It was quite the frustrating ordeal having that convo with them. They didn't see it as an issue.

Drove the car off the lot and immediately heard grinding and had gear changing issues (between 1-2 and again between 6-7). Took it back to them and they said the TCM got wiped somehow and needed to be reprogrammed. Did that and car worked fine for about a day. However, the lights did return. Got pretty pissed this time with them and got FCA Cares involved.

Returned car to same dealer who stated the clutch had burned out (surprise surprise) and recommended an entire trans replacement. I just got the car back yesterday. Has been over 2 months back and forth in their shop. FCA Cares couldn't care less. All they did was provide some assistance with checking in on the work the dealer was doing and reporting back to me. They were otherwise useless and callous.

Thank God I had a service contract on the vehicle otherwise I would have been looking at close to 10k in total repairs. Nevermind all the lost time and money on traveling back and forth because I thought it was fixed, renting/borrowing other vehicles, etc. I fully intend on trading this awful vehicle in as soon as I can and letting Fiat have it wherever I can.

Wondering if anyone else has had their trans replaced and it solved any issues? Again, I have always suspected the issue was electrical. I doubt the trans is the actual issue. Perhaps a result of something larger - but not the primary issue itself. Fiat doesn't seem to care to figure it out.

I haven't done much to my car since my last post. The error is quite random, comes and goes but there is some sort of a pattern, the temperature of the gearbox. The warmer it gets, the more likely the error might appear. Once it cools down , the problem is gone. I've done some work on electricals, disconnected and cleaned all possible connectors, ECM and TCM, fuse boxes, rear axel, etc. and the difference is quite significant. The gearbox shifts much better, more consistent and predictable. Also my forward collision warnings works every time. Same radio, it used to lose sometimes stations or turned itself off on wet or cold days, now it's always fine. Despite that, the gearbox problem remains. I searched a lot of different forums, English ones as well as international, Spanish, Italian, German and came across a company called Gearlab http://www.gearlab.com.ar in Argentine on one of the Spanish forums https://www.opinautos.com/fiat/toro/defectos/diferencial, which managed to figured out what is the problem in case of P1DB7. So I got in touch with them, called first and then exchanged several emails. According to them, the problem is mechanical, down to a particular part within the gearbox: "The DTC P1DB7 refers to the performance of the Torque Converter Clutch lockup. This failure occurs after the transmission exceeds the temperature above 70c° and is the car is still driveable? If so, the problem is solved by changing a hub that is located at the tip of the Stator shaft that is in the pump.". Unfortunately, the gearbox needs to be removed to accomplish it. They are an authorised ZF's partner, therefore my guess is, ZF has helped them to find out what is the problem and how to fix it. I found a company in Bristol https://bristolgearbox.co.uk/, which is prepared to do it. My plan is, once the weather gets back to normal, at least 15c°, to get this done.

 

[FCA]

By the way, I drove a 3 years old, 2nd hand Toyota Prius for over a year before getting my 500X and have had a lot of electrical issues with that car, radio - no stations on wet/cold days, forward and reverse cameras failing, cruise control failures, electric windows stopped working all together, overheating engine on several occasions, etc. A disaster of a car. All issues addressed under the 5 years Toyota warranty but unfortunately most of them never resolved. I was relieved, once I got rid of it. Terrible handling on top. Even my kids were saying, the car feels so wobbly and unsafe when driving. Neither the economy was great, around 35-38 mpg on average.

 

[Ralf S.]

This sounds similar to a problem my brother-in-law had, amongst a load of other problems, with his Merecedoos ML250 (don't quote me.. but it was a 4x4).

If it seems that nothing else is wrong then the error must be wrong. Electrical anything doesn't like being hot.. including sensors. They run at a higher internal resistance and so are more likely to fail. TDC sensors are the best known example.

Swap the sensor (it's probably £600 plus parts and labour if it's made by the same firm Merc' uses) and that could sort it.

There may be a digital way to test/verify it, such as boiling it in oil and measuring the resistance/signal output.. but I dunno. An auto electrician might know how it's supposed to act and can measure it.


Ralf S.

 

[PatrickSeb]

I was beginning to think I was the only person in the world experiencing this problem. My 2016 500x 4x4 2ltr diesel auto has been throwing out ‘transmission error’ messages - usually after about 1 to2 hours at motorwayspeeds. The rest of the time everything works fine. I have recently had an independent auto box specialist run diagnostics (I don’t trust fiat) and they have identified the P1DB700 code - torque converter - as being the problem.. there are also a couple of other BCM codes that relate to ‘circuit shorts’. My personal thoughts on the matter (and I’m no expert) lead me to think that it’s a wiring or gearbox temperature issue. I’m reluctant, and don’t have unlimited funds, to spend on a gearbox rebuild that, from the experience of others, may not sort the issue. I also note that there was a recall on part of the wiring loom for 2016 500x autos, but my fiat garage denied this was applicable to my vehicle (which is why I don’t trust them), I will be following this up... As experienced by others, if I just ignore the warning messages, everything returns to normal after a couple of ‘turn it off, turn it on again’ restarts, and I have driven several hundred miles with a selection of red and orange warning lights blazing - not what I would normally be happy doing. I was informed that after any warning message, the stop start light and engine warning lights will appear, and not to worry too much about them. I tend to go along with this line of thought, because they disappear within a few off/on restarts as mentioned above. The only mechanical issue I have when the transmission light appears is that there’s no specific drive modes available (sport and traction) and the default eco mode, although changing up/down perfectly well, doesn’t seem to provide any engine breaking, and has a slight slippage when accelerating hard for a motorway overtake (a bit like auto gearboxes of the olden days). I would welcome any advice from the forum about how accurate these fault codes may be, or whether given the complexity of the software in these vehicles (there appear to have been several updates) this might be where the fault could be. Meantime I’m going to try and locate every possible wiring connector and do some cleaning...