P1741 Engagement Potentiometer Issue

[Maseratiscot]

Hi folks, hopefully you can help me with this one. Last week I couldn't start my 2003 Coupe as it was coming up with the engine management light and the gearbox warning light, like this:



So, I got myself a Launch X431 Pro Elite V - what an excellent piece of kit, it was able to tell me that I have a "P1741 Engagement Potentiometer" issue.



So I got my brother to help me, he is more mechanically minded than me. After a bit of research online we decided to source the starter motor relay which is in position M, under the passenger footwell, and we ran a wire from the 85 grounding pin to the metal door hinge.


We then got the car started, I can't recall if we reset the codes or not first .... I was too surprised! Anyway, got the car moving forward, backward and then went out for a 10 mile test run - all good. Started, stopped several times - all business as usual.

However, several hours later, I have just tried to start it again and back to same issue, albeit with more information. So wasn't just a one off, would need to find root cause and fix .... I could repeat the process but it looks like it's going to happen regularly. I had thought the problem started when I left the car in neutral with handbrake off by mistake and it rolled a few feet, but that may be a red herring.

There's not too much info on this issue out there, so hoping I can get a bit of direction. I'm in Scottish Highlands with nearest Maserati specialist about 180 miles away. This is my first problem in 3 years of ownership.

 

[Zep]

Sound like what your brother did was bypass the permission to start signal from the TCU which enables the starter. If it was then removed, it will then revert back to not working.

It won’t be because of the handbrake and neutral, unless you ran something over. It’s going to need looking at by someone who knows their way around it.

 

[Zep]

Oh, and welcome to the forum.

 

[Maseratiscot]

Sound like what your brother did was bypass the permission to start signal from the TCU which enables the starter. If it was then removed, it will then revert back to not working.

It won’t be because of the handbrake and neutral, unless you ran something over. It’s going to need looking at by someone who knows their way around it.

Sound like what your brother did was bypass the permission to start signal from the TCU which enables the starter. If it was then removed, it will then revert back to not working.

It won’t be because of the handbrake and neutral, unless you ran something over. It’s going to need looking at by someone who knows their way around it.

Thanks, yes that makese sense - I reckon I'll need to get it to a specialist.... at least we know a bit more now than we did

 

[safrane]

I note from the photo that the car is in 1st Gear. With the ignition on, and foot on the brake will it go into N?

If not it may be a F1 pressure issue, fluid level, or clutch issue.

Are you still on the original clutch, or have you had one fitted before 2016?

 

[Maseratiscot]

I note from the photo that the car is in 1st Gear. With the ignition on, and foot on the brake will it go into N?

If not it may be a F1 pressure issue, fluid level, or clutch issue.

Are you still on the original clutch, or have you had one fitted before 2016?

Yes, it was going into Neutral OK but now seems intermittent. There was a new clutch fitted at 49K miles (previous owner, summer of 2014) and it's now at 65K - the X431 is coming back at 51% wear, but I know that's an estimate. I'll read up on checking the F1 fluid level - thanks.

 

[safrane]

Check the brake lights are coming on - if not the switch under the pedal may be faulty and it requires the signal to start the car.

 

[Zep]

If it was fluid you’d get a code.

If it is the brake switch, you don’t get any codes at all, because it doesn’t know it’s not working, it just doesn’t start.

P1741 is def potentiometers. That you can bypass the start enable and it works suggests it is intermittent at the moment.

Have you actually reset the codes and do they show as active or absent when you read them in the actual module?

 

[Maseratiscot]

If it was fluid you’d get a code.

If it is the brake switch, you don’t get any codes at all, because it doesn’t know it’s not working, it just doesn’t start.

P1741 is def potentiometers. That you can bypass the start enable and it works suggests it is intermittent at the moment.

Have you actually reset the codes and do they show as active or absent when you read them in the actual module?

Thanks for the info .... yes, the codes were reset and everything was fine on a test drive ..... now the P1741 code is back as present and it won't start, this was a few hours later.

I'm sure it would work again by repeating the relay earthing process to bypass the permission to start signal from the TCU and therefore enabling the starter .... which makes me think about putting a permanent earth connection in ..... so I could drive 200 miles to a specialist and get it looked at.

 

[Zep]

Hmmm. If you do the bypass the fault clears (or goes to absent)?

 

[Maseratiscot]

Hmmm. If you do the bypass the fault clears (or goes to absent)?

Yes, started the car, could then clear the codes and then drive fine for a 10 mile test run, stopped and started fine in that time too - then left the car for a few hours...

I switched off battery in back as I wasn't going to use until next weekend (mine seems to eat batteries and I just put in a new one too) but I thought I'd start it again this afternoon and the P1741 code came back and car would not start again.

 

[Zep]

Do you get the P0725 code too?

 

[Maseratiscot]

Do you get the P0725 code too?

No, just back to the P1741 - Engagement Potentiometer .... I've emailed some specialists and will see if I can get it booked in. BTW, first problem in 3 years and one day I knew I'd need to get it trailered 300 miles away to the nearest specialist - no regrets though!