P0715 Transmission Error - Hold light
Posted: Tue May 02, 2023 9:38 pm
Hi
I have just bought my Bongo and on the way home experienced the flashing Hold light as well as other issues.
You kind of expect to have some problems on a 23 year old vehicle that hasn't been bought from a reputable dealer.
Mine was a private purchase and i didn't experience this issue when i took it for a test drive.
The Bongo was suffering from a number of issues that resulted in the flashing hold light and when it was on the gearbox seemed to be locked into 3rd and would stall at junctions.
It also stalled when warm on idle, when selecting D or R. This was another issue that was resolved by new plugs, oil change, air filter, fuel filter, vacuum solenoids, Idle control vale clean and throttle body clean. Generally a really good service.
But after all this on my next run, all was fine and then the dreaded hold light appeared.
It was stuck in 3rd again and stalled as soon as I came to a stand still at the junction.
I restarted the vehicle and it was fine all the way home.
2nd run out and it did it all again.
I checked for error fault codes and the transmission found P0715 (transmission input/turbine speed sensor circuit)
After much research this indicated either input or output speed sensors on the gearbox, torque convertor or wiring.
I called a few Bongo specialists and they suggested it would need further diagnostics to really understand the problem.
Although they indicated anything from clean & check sensors/wiring, new solenoids or change the gearbox.
None of them are close to me and my nearest automatic gearbox specialist wanted £88+vat just to road test and run diagnostic test.
Not really sure what else they were going to find without actually working on it.
Weighing up the price of solenoids (£400+ for the V6 petrol) or the price of a 2nd hand box £500 ish, I thought I might as well check it myself first.
I removed the 2 sender units from the side of the box. 10mm bolt and unplug.
The front one was not too bad but the back one was covered in a very dark black substance.
I am aware the transmission fluid needs changing. It was nearly 1 litre below maximum when hot and is a rusty brown colour. Not the worst i have seen on some videos but I decided to top it up first when I bought it. So these sensors have confirmed a drain/refill is required.
With the 2 senders cleaned I researched how to check them.
This is not that easy. You can test the live feed and possibly the return feed but that's not easy when lying on your back with an inch of room between your nose and a dirty gearbox sump. The live feed was around 11 volts which is within spec.
There is a test you can do on the sensors themselves but you need the engine running and hold a spanner near the sensor to test the voltage change. Not a job for today.
Everything was put back together. Fault codes cleared and off for another test drive for over 25 minutes.
Im really pleased to say that the hold light didn't come on and the gears all seemed to select better.
The overdrive appeared to be working and it sat at 50mph at 2000rpm, 60mph at around 2500 rpm.
I tried stopping where possible and it didn't stall once.
When I got home I checked for error codes and there was none.
Hopefully this has resolved the problem.
So I thought I would post this as a new topic just in case someone else has the same issue and it might just help you save a few pounds.
see images for location of sensors (Input at the front, output at the rear)
I have just bought my Bongo and on the way home experienced the flashing Hold light as well as other issues.
You kind of expect to have some problems on a 23 year old vehicle that hasn't been bought from a reputable dealer.
Mine was a private purchase and i didn't experience this issue when i took it for a test drive.
The Bongo was suffering from a number of issues that resulted in the flashing hold light and when it was on the gearbox seemed to be locked into 3rd and would stall at junctions.
It also stalled when warm on idle, when selecting D or R. This was another issue that was resolved by new plugs, oil change, air filter, fuel filter, vacuum solenoids, Idle control vale clean and throttle body clean. Generally a really good service.
But after all this on my next run, all was fine and then the dreaded hold light appeared.
It was stuck in 3rd again and stalled as soon as I came to a stand still at the junction.
I restarted the vehicle and it was fine all the way home.
2nd run out and it did it all again.
I checked for error fault codes and the transmission found P0715 (transmission input/turbine speed sensor circuit)
After much research this indicated either input or output speed sensors on the gearbox, torque convertor or wiring.
I called a few Bongo specialists and they suggested it would need further diagnostics to really understand the problem.
Although they indicated anything from clean & check sensors/wiring, new solenoids or change the gearbox.
None of them are close to me and my nearest automatic gearbox specialist wanted £88+vat just to road test and run diagnostic test.
Not really sure what else they were going to find without actually working on it.
Weighing up the price of solenoids (£400+ for the V6 petrol) or the price of a 2nd hand box £500 ish, I thought I might as well check it myself first.
I removed the 2 sender units from the side of the box. 10mm bolt and unplug.
The front one was not too bad but the back one was covered in a very dark black substance.
I am aware the transmission fluid needs changing. It was nearly 1 litre below maximum when hot and is a rusty brown colour. Not the worst i have seen on some videos but I decided to top it up first when I bought it. So these sensors have confirmed a drain/refill is required.
With the 2 senders cleaned I researched how to check them.
This is not that easy. You can test the live feed and possibly the return feed but that's not easy when lying on your back with an inch of room between your nose and a dirty gearbox sump. The live feed was around 11 volts which is within spec.
There is a test you can do on the sensors themselves but you need the engine running and hold a spanner near the sensor to test the voltage change. Not a job for today.
Everything was put back together. Fault codes cleared and off for another test drive for over 25 minutes.
Im really pleased to say that the hold light didn't come on and the gears all seemed to select better.
The overdrive appeared to be working and it sat at 50mph at 2000rpm, 60mph at around 2500 rpm.
I tried stopping where possible and it didn't stall once.
When I got home I checked for error codes and there was none.
Hopefully this has resolved the problem.
So I thought I would post this as a new topic just in case someone else has the same issue and it might just help you save a few pounds.
see images for location of sensors (Input at the front, output at the rear)