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453 Speedo Warning Faults

Mod Details
PremiumNo Difficulty Mod ID1492 Creditevilution For453 EQ453 Fortwo/Forfour Linkhttps://www.evilution.co.uk/mod/453-stopstart-and-general-faults.htm Copy to Clipboard

So far, almost all errors I have seen appear on the dashboard LCD have actually had nothing to do with the fault being described. For example, this is a stop/start malfunction.

Ignore what the car is telling you. Almost every single occasion, the fault is with the battery. The rest of the page will be interspersed with various faults that are all actually a battery problem.

But I Thought The Stop/Start Battery Was Better

Yes, stop/start batteries are usually AFB/EFB or AGM type instead of the old SLA car battery types. They are designed to start the car 3 or 4 times more than the old battery type.

SLA – 30,000 starts.
AFB/EFB 85,000 starts.
AGM 120,000 starts.

The 453 battery is an AFB (Advanced Flooded Battery) so you’d expect it to be good. Especially considering how much more expensive they are compared to SLA batteries.

So, Why Are There So Many 453 Battery Failures?

The problem lies with what you are expecting the battery to do. It could be required to start the car 5 times a minute in a traffic jam.

To do this, it needs the power to start the car. If the car is only running for 10 seconds, the car has to put a lot of power into the battery as quickly as possible. To do this, the alternator forces up to 16.5 volts into the battery. Over voltage on the old SLA battery was a bad idea. Over voltage on an AFB type is worse.

AFB type batteries suffer very badly if over charged. They quickly lose capacity to the point that they can’t fully power all of the elctrical systems. The lack of power causes an error in that module which then brings up an error on the screen.

What’s The Fix?

Step 1 is obviously to buy a new battery.

Step 2 is to turn off stop/start when ever you remember.

There is no proof that this will stop the over voltage but the car does monitor the battery voltage so, if the stop/start isn’t draining the battery, the voltage shouldn’t get low and the car won’t need to excessively charge it.

The next step for me is to look into the coding to see if I can reduce this 16.5 volt charging to something sensible.

But My Battery Is Fully Charged

When you charge a car battery, it adds volts but volts isn’t the only factor. If you connected 8x AA batteries in series, you’d get 12 volts out of that pack. However, you know that wouldn’t be powerful enough to power a car. You need voltage and amps and this creates watts. This is the capacity of the battery.

As these cheap batteries degrade, they lose capacity. The car expects an unreasonably high current output. Otherwise is panics and you get error codes.

Does A New Battery Need Coding?

Nope. Doesn’t matter what other people on forums say, they are wrong. There are no coding options in Xentry. It just measures the capacity and eventually realises that the battery has more available power.

Recommended Battery

Do yourself a favour and buy an AGM 027 battery.

In 2021, 2022 and 2023 I bought 3 separate 027 AGM batteries from Halfords. They have a 5 year warranty but the price went up every time. They started at about £120 but now increases in 2023 to about £150.

That’s when I went over to buying the Duracell 027 AGM with a 3 year warranty – click here.