RBS not smooth, shocking. Any ideas?

[LUw]

Hi fellow Outlander Owners,
Happy to join the family. Few months ago we've bought a 2013 version, and so far very happy.

Since 2 weeks however the regen breaking isn't smooth anymore. It's like you hit the break, and let it go, and hit it again, every 1 second. Instead of a smooth decline. The more breaking or higher B setting, the more strong this happens. The info screen also shows regen power move to the battery in the same ritme, (like regen is turned on off on and so on). This makes driving very unpleasant.

Anyone any experience with this and or an idea what could be wrong?

 

[AndyInOz]

A few possibilities spring to mind.

1. If you have a sticking brake caliper, the combination of manual brake plus regenerative braking may be causing the car to brake harder than required, and this is confusing the braking system.

2. You could have a failed/damaged wheel sensor which is triggering the weird behaviour.

3. If you've ended up with mismatched tyres for some reason, this could be triggering stability control. (No idea why this would only be apparent under regen though)

4. An electric fault somewhere else is causing current flow to be too high, causing regen to rapidly turn on and off.

Step one is to get someone to connect a computer (diagnostic tablet) to the car and check for error codes.

You need a mechanic who is good at fault finding in modern cars.

 

[michael8554]

Modulated braking like the OP describes is how the ABS handles panic braking.
In between the ABS pulses on the real brakes the OP is seeing regen pulses going to the battery.
Sounds like an ABS fault.
No warning lights on the dash?

 

[LUw]

A few possibilities spring to mind.

1. If you have a sticking brake caliper, the combination of manual brake plus regenerative braking may be causing the car to brake harder than required, and this is confusing the braking system.

2. You could have a failed/damaged wheel sensor which is triggering the weird behaviour.

3. If you've ended up with mismatched tyres for some reason, this could be triggering stability control. (No idea why this would only be apparent under regen though)

4. An electric fault somewhere else is causing current flow to be too high, causing regen to rapidly turn on and off.

Step one is to get someone to connect a computer (diagnostic tablet) to the car and check for error codes.

You need a mechanic who is good at fault finding in modern cars.

Thank you so much for taking the time to lists some options.

I'll check the car brakes, pads and cables around first. Then if nothing is off, I'll go a garage for some diagnose.
I'm used to cars that I can fix myself for 90%, but now have a car that is complex and much electrically managed. Have to due to the taxes, I pay a lot less tax for this big PHEV than previous ICE Cars from 2002-2005.

Thanks and I'll post here if I find the cause of the weird breaking behaviour.

 

[DaveL59]

another area to check is the bushes at the rear axle on the motor/transfer casing, since wear there will lead to the drivetrain rocking when moving away/braking.

 

[LUw]

Modulated braking like the OP describes is how the ABS handles panic braking.
In between the ABS pulses on the real brakes the OP is seeing regen pulses going to the battery.
Sounds like an ABS fault.
No warning lights on the dash?

Thank you for the comment.

No warning lights on the dash. Only occasionally ACC service required.

Also nothing when reading with OBD. I've checked the breaking pads, they all seem okay. Wheels are also similar all around.

I've discovered the regen will also never go deep into the blue area. Only a little when breaking. No matter what B-setting or how fast I drive and break.. the regen level will only go slightly into the blue. I've read others say their regen goes all the way, sometimes even until the end of the blue area. This tells me the regen is not working at all, or at least maybe only for 10%.
Not sure if this problem is related to the "pulsed" breaking problem.

About the breaking, it's not only that the little amount of regen goes "on/off/on/off etc". But the actual breaking also goes in pulses. So the actual physical breaks follows the same pattern as the regen breaking. Manually hit the breaks and let B5 'work' behaves the same. Sometimes I feel like B5 is actually not breaking the car more, even though B5 is set, it acts like B1.

Could it still be ABS sensors even though there are no error shown in the dash?