I have a 2.3l Fiat Ducato having problems with the comfortmatic gearbox. When trying to select gear saying gesrs unavailable to select. But if I tap the pump when key is just turned on before starting will be fine, do I need to change pump and motor looking for the correct parts
Technical Fiat Ducato 2017 comfortmatic problem
- Thread starter Stevepot
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Technical
Fiat Ducato 2017 comfortmatic problem
Can you please explain what you mean by tapping the pump? To correctly diagnose what the issue is the best advice I can give is to use Multiecuscan to view fault codes and also live parameters.
If you are referring to the hydraulic pump, then it may be about to fail completely. What year was the vehicle manufactured and how many k's has it travelled. It may have a leaking pressure accumulator, which will lead to the pump failing. You will be able to diagnose quickly with MES. It may even be an electrical connection issue.
As I said, it may be electrical - which includes the wiring and connectors, the pump itself, and the pressure regulating switch. MES is an abreviation of MultiEcuScan - the best diagnostic software you can get for the Fiat Ducato: https://www.multiecuscan.net/
MPN
Member
Hi, Bonjour Steve,
I have experienced similar symptoms (gearbox hydraulic pump would intermittently fail, then after a period (of cooling?) it would temporarily resume operation). This is a very tricky fault as “Gears not available” indicates on the dashboard display and it renders the vehicle immovable under its own power (very embarrassing at a big intersection). Using my diagnostic scan tool I could see the relay function and gearbox hydraulic pump cycling every 2/3 gear changes (boosting hydraulic pressure from low limit of 36 up to 46 bar). When the fault occurred, the pump failed to reboost hydraulic pressure and the pressure dissipates below 35 bar (dashboard “no gears available” warning illuminates).
With this diagnosis, my local Fiat Professional dealer quickly misdiagnosed the fault, saying they’ve seen it many times, and strongly recommended replacement of the clutch master cylinder, clutch and dual mass flywheel for a cool $14k! I walked away, determined to fix it myself.
I confirmed the faulty 12v pump motor by initially confirming both relay and 30 amp (green) fuse serviceability (I replaced them with new for $55, just in case there was an intermittent fault), then tried bypassing the 12v wiring loom with a dummy supply wire. Then again the gearbox worked perfectly for 40 gear changes then bingo, same “no gears available”. Based upon this I ordered a new pump and accumulator (accumulator was changed due to relative cheap price, gained access and importance for offloading the hydraulic pump mechanism).
I ordered pump and accumulator (received in 5 days to NZ!) from this excellent German part supplier https://www.sequparts.com/product-c...MI3MK7xJDxkQMVHs4WBR34GDcFEAAYASAAEgJJmPD_BwE
To change the pump I first placed the van on highest levelling blocks under the front wheels (you need to gain 125mm) and safeguarded the van from unwanted movement with chocks and axle stands. Remove the battery and battery box in the cab (easy 20 minute job).
Then whilst under the van but using the battery box hole for extra arm articulation space and a far less claustrophobic environment. Vitally I used a Kingchrome mini T20 Torx ratchet ($23 for a set and this tool - or similar micro Torx ratchet- is essential due to confined space around the pump motor. This ratchet is about 3.5” long and fits any bit).
For further access, I removed the single wire electrical plug from the 12v motor, and the multi wire plug from the adjacent hydraulic pressure sensor, I also removed one of the DPF sensors for better access (this will become obvious when you’re under the van).
Then using the T20 mini ratchet you need to undo the 3 short screws (two are diametrically opposed, whilst the other is the pump earth connection) that hold the 12v pump to the gearbox hydraulic power pack. This is easily achieved by methodically working in an uncomfortable but very doable position for anyone who considers themselves a competent vehicle DIYer (i.e. confident in performing oil changes, brake pads replacement etc). Take care to keep the screws captive in the T20 bit until recovered in your hands, as dropping them could waste valuable time. Once al, three screws are removed, get from under and have a cup of tea, before the important second half begins! The reason for this break becomes evident as the pump can only be extracted in a certain position and angle, once you find this it’s voila! Do not be impatient and risk damaging anything (you’re working directly under the LPEGR Valve) keep logically trying different positions until you find the angle, then try to commit it to memory lol.
Now out you can compare the parts, noting the new one is exactly the same. At this point ensure you rotate the new pump’s oblong shaped drive, to the ‘same position/angle’ as the removed one! This one simple task can save you lots of heartache.
Then in the infamous Haines Manual speak: refitting is the opposite of removal.
Consider ensuring the mating face is clean and clear by wiping with a clean cloth and refit. When installing the screws, to prevent dropping them, I doubled over a 10” strip of electrical insulation tape and punched a hole in the end for the T20 screw thread. The idea here is to prevent inadvertent loss of the screw and avoid drama, as if you drop the screw - you just gently pull on the tape and recover it and start again. Then once the thread is safely engaged a few turns (due to the confined space the micro ratchet will tighten one click at a time), you can pull the tape off the screw and discard it. Loosely engage all three screws, remove all the retrieval tape, then torque the 3 screws evenly (to ensure the pump is fitted flush) to two white knuckles (good luck getting a torque wrench in there!).
If you’re still with me, and thinking this sounds tricky, it is. BUT BE ASSURED I REMOVED AND REPLACED THE PUMP IN ABOUT 1 HOUR (2 hours including start to finish and test drive). You can do this.
I now believe this is a symptom of water ingress from the infamous Ducato scuttle area which tracks down and sits around the gearbox hydraulic pump earth connection……but this is only reasonable suspicion, based upon the corrosion present in that area despite the pump having a galvanised body. My Ducato 290 van is 2017 and 21,000 km, but had scuttle leak evident in engine bay when I bought it.
Finally, it’s also important to separately replace the fluid of the gearbox hydraulic system (Penrite LDAS) and clutch mechanism (Dot 4) a few times. These fluids go largely unchecked and never replaced but can get contaminated and cause wear. For these you’ll need diagnostic gear to perform clutch maintenance tasks like bleeding and calibration (certainly worth buying for a few hundred dollars and keep away from the dealers!). But note, this is a separate concern to the described intermittent fault on the Comfortmatic gearbox 12v pump.
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Re the failing pump - it is quite often brought on by a failing pressure accumulator rather than pump corrosion. If the accumulator begins to fail, that places the pump in an operational condition it was not designed to perform in and will quickly overheat due to an increased duty cycle.
MPN
Member
Agree 100% deejays, especially as my van was nearly 8 years old (despite low km). Indeed your exact statement was my very logic (my pump typically failed 10-20km away from home) to consider the accumulator as an economically prudent (money, time and knuckle skin) extra purchase whilst planning to replace the 12v pump.
For anyone in the same “no gears available” drama, I would recommend this extra purchase whilst planning the repair, it could even be replaced before tackling the 12v pump (which is much trickier to replace) to see if it improves the situation (same access with battery box out, ensure hydraulics not charged, and it’s a single socket with breaker bar to undo (easy 5 minute job).
I had also previously changed the gearbox robot hydraulic fluid 2/3 times in an effort to flush out as much of the old fluid in the closed hydraulic system, and considered taking off the accumulator at the end of the power pack just another way to aid this process.
I never tested my vehicle after the simple accumulator change, as it would have required reassembly of the battery box etc to put power back on the original 12v pump and driving the vehicle, but I was over risking getting stuck at traffic lights. As such I considered it a standard replacement part under the circumstances, and cracked on with testing my yoga skills in wrapping myself around the crossmember and removing the 12v pump blind using an improvised mechanical Braille technique
.BTW, now 4,000 perfect gear change kilometres have been covered since pump and accumulator replaced (and fluids replaced). It’s so nice to not break into a sweat as the traffic lights change to red, and you stare at the dashboard display of doom. Good luck everyone.
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