Clearing Dashboard Warning Lights

click86

I had my car battery voltage checked yesterday, unfortunately when it was raining heavily.

This morning, I started the car up and a few amber dash warnings were showing.

- Engine management

- Auto stop/start

- Generic exclamation mark in a triangle

I took the car out for a long run, hoping they would clear themselves. Unfortunately they didn't.

I plugged in the ODB2 and a P1220 error came back. Looks like this is related to the throttle sensor.

As there was no resistance, rough idling or increased fuel consumption, I cleared the error.

Now I have cleared the error, will the light come back on if it finds the error again?

I do think it was due to water ingress due to the timing on this occasion but just want to make sure!

daveyjp

Whether its raining or not makes no difference to checking a battery.  Why check it and what did it say?  How old is the battery?

If the battery is failing it can throw up lots of faults.  Plugging in readers is therefore a very good way of finding false flags and leading you on a potentially expensive wild goose chase,  but it doesn't sort out the underlying problem of a dying battery.

chrisw

click86 said:

Now I have cleared the error, will the light come back on if it finds the error again?

If there's genuinely a fault with the throttle sensor, the light will come on again. 

For minor glitches the ECU may store a pending fault code and only if that fault occurs again in so many starts will it put on the management light.

click86

chrisw said:
If there's genuinely a fault with the throttle sensor, the light will come on again. 

For minor glitches the ECU may store a pending fault code and only if that fault occurs again in so many starts will it put on the management light.

Brilliant, thank you!

Nearlyold

If the battery is on its way out, as a temporary measure you can help prevent any false warning lights by turning the ignition on then waiting for all the lights to go out - (with the obvious exception of the ones that show when the car is not running) before engaging the starter. Otherwise the excessive voltage drop when you start the car can mimic a fault to the sensors that run an initial check.