Recent Posts
1
Honda Jazz Mk4 2020 - / Re: Best driving technique for long, steep highway climbs (58% gradient)?
« Last post by ahavoja on August 10, 2026, 05:22:08 PM »Climbing a 6% uphill at 100 km/h requires 21 kW of power.
(Calculation: 1300kg * 9.81m/s² * 0.06 * 100km/h / 3.6 = 21kW.)
On top of that the aerodynamic drag at 100km/h requires additional 15kW.
This would mean a total of 21 + 16 = 36kW required. This is already 46% of the maximum 79kW output of the petrol engine of Jazz. This could be why the engine is roaring loudly. Only two solutions come to my mind: driving slower or wearing noise canceling headphones.
When I drove up some mountain roads in Norway, I just tried to enjoy the roaring engine sounds of Jazz. Regardless of the noise, the car dealt quite well with the steep climbs.
(Calculation: 1300kg * 9.81m/s² * 0.06 * 100km/h / 3.6 = 21kW.)
On top of that the aerodynamic drag at 100km/h requires additional 15kW.
This would mean a total of 21 + 16 = 36kW required. This is already 46% of the maximum 79kW output of the petrol engine of Jazz. This could be why the engine is roaring loudly. Only two solutions come to my mind: driving slower or wearing noise canceling headphones.
When I drove up some mountain roads in Norway, I just tried to enjoy the roaring engine sounds of Jazz. Regardless of the noise, the car dealt quite well with the steep climbs.
2
Honda Jazz Mk4 2020 - / Re: Jazz vs bigger cars
« Last post by emp on August 10, 2026, 04:20:55 PM »3
Honda Jazz Mk3 2015-2020 / Re: Under bonnet.fuse/relay box label
« Last post by orcadian on August 10, 2026, 04:09:44 PM »Paul,
Many thanks for actually answering the query about relays (which was in the title) I wish I had never mentioned the other stuff in passing - as this is our second 3rd gen Jazz, I am familiar with the stop start foibles of temp and switch positions and actually chuffed that it doesn't work!
Yes, the relays are located in different places, not just from 1st and 2nd gen but even across 3rd gen variants and with no chart to help, I think ours is in the smaller box on the drivers side (UK model)
There are not so many in there, so I can remove one at a time and bench test each one. Hopefully I'll find a duffer - but the fault could be in a software program which is preventing the air con clutch from engaging. My diagnostic gear (Icarsoft) doesn't list air con faults on Honda.
Ian
Many thanks for actually answering the query about relays (which was in the title) I wish I had never mentioned the other stuff in passing - as this is our second 3rd gen Jazz, I am familiar with the stop start foibles of temp and switch positions and actually chuffed that it doesn't work!
Yes, the relays are located in different places, not just from 1st and 2nd gen but even across 3rd gen variants and with no chart to help, I think ours is in the smaller box on the drivers side (UK model)
There are not so many in there, so I can remove one at a time and bench test each one. Hopefully I'll find a duffer - but the fault could be in a software program which is preventing the air con clutch from engaging. My diagnostic gear (Icarsoft) doesn't list air con faults on Honda.
Ian
4
Honda Jazz Mk4 2020 - / Re: Software update
« Last post by RA273 on August 10, 2026, 02:58:53 PM »my last adventures with Honda crapware
the first irritator: the last infotainment system update or whatever they call it.
It kept hanging on installing, several attemps made (abort update then retry).
Tried with connection to my home wifi and via hotspot on phone, made no difference.
After wasting maybe two hours in total, I contacted the dealer and the only thing they came up with was a "factory reset" and then try to install the update.
After some hesitation I did this, and finally after some 40 minutes it was reset and the update installed.
Then had to spent another hour to get all my tweaks back, redo all radio station presets, icon order, etc. etc.
When finally finished I decided that I will totally ignore any future Audio updates.
The second irritator came a few weeks later: the reconfirmation of ownership via the MyHonda+ app.
It kept asking for re-login and seemed to not recognize my account anymore.
You can feel it coming: I deleted the app from my phone and also disabled the location data sharing in the car.
Tried to delete my account but that seems to be impossible. Anyway I'm done with it, not interested anymore.
Just keep it this way until my next car, which will be an EV, and as Honda has nothing to offer in that area it will be bey-bey after 5 Honda's.
So sad that Honda's software quality is in sharp contrast to their brilliant eHEV hybrid system
the first irritator: the last infotainment system update or whatever they call it.
It kept hanging on installing, several attemps made (abort update then retry).
Tried with connection to my home wifi and via hotspot on phone, made no difference.
After wasting maybe two hours in total, I contacted the dealer and the only thing they came up with was a "factory reset" and then try to install the update.
After some hesitation I did this, and finally after some 40 minutes it was reset and the update installed.
Then had to spent another hour to get all my tweaks back, redo all radio station presets, icon order, etc. etc.
When finally finished I decided that I will totally ignore any future Audio updates.
The second irritator came a few weeks later: the reconfirmation of ownership via the MyHonda+ app.
It kept asking for re-login and seemed to not recognize my account anymore.
You can feel it coming: I deleted the app from my phone and also disabled the location data sharing in the car.
Tried to delete my account but that seems to be impossible. Anyway I'm done with it, not interested anymore.
Just keep it this way until my next car, which will be an EV, and as Honda has nothing to offer in that area it will be bey-bey after 5 Honda's.
So sad that Honda's software quality is in sharp contrast to their brilliant eHEV hybrid system
5
Honda Jazz Mk4 2020 - / Re: Best driving technique for long, steep highway climbs (58% gradient)?
« Last post by Sean Regan on August 10, 2026, 02:49:53 PM »I've a 23reg Crosstar. I drive everywhere in B, sometimes up a steep hill. Never bother about it, I just let the car get on with it. "It knows what it's doing."
6
Honda Jazz Mk4 2020 - / Re: Best driving technique for long, steep highway climbs (58% gradient)?
« Last post by jasonevans on August 10, 2026, 01:57:55 PM »I found a steady throttle application helps rather than flooring the accelerator.
7
Honda Jazz Mk4 2020 - / Re: Best driving technique for long, steep highway climbs (58% gradient)?
« Last post by Nicksey on August 10, 2026, 01:20:49 PM »Are you in D or B mode?
I have a few steep hills in the wolds around me, and because they are generally minor roads I drive in B. I haven't had any issues ascending hills.
I have a few steep hills in the wolds around me, and because they are generally minor roads I drive in B. I haven't had any issues ascending hills.
8
Honda Jazz Mk4 2020 - / Re: Best driving technique for long, steep highway climbs (58% gradient)?
« Last post by Downsizer on August 10, 2026, 11:30:44 AM »What happens if you select a suitable speed in cruise control after setting off and let the car decide for itself?
9
Honda Jazz Mk4 2020 - / Re: Jazz vs bigger cars
« Last post by Jazzfan49 on August 10, 2026, 10:53:45 AM »A CRV Hybrid is £48k but the HRV starts from £32k and has basically the same powertrain as the jazz, its fuel economy is 52mpg combined according to Honda uk although I am getting a genuine 58/60mpg out of mine with a fairly light right foot, the CRV has a 2litre engine and Honda quote 5.2/8L /100km (35/54mpg) and its a big car, the HRV sits roughly between the Jazz and CRV sizewise why not go and try one 
10
Honda Jazz Mk4 2020 - / Re: Best driving technique for long, steep highway climbs (58% gradient)?
« Last post by Bristol_Crosstar on August 10, 2026, 10:40:41 AM »It helps if the battery's near full at the start of the climb, to achieve this you could switch the climate system off then switch it on again at the top of the hill. Also I try and keep the throttle steady rather than putting foot to the floor if possible.
