Car Stalls at stop lights or in traffic after replacing battery

JERRY A.

MEMBER
2007 MAZDA CX7
1.2L
4 CYL
TURBO
2WD
AUTOMATIC
102,000 MILES

I replaced my car battery, and has been stalling at traffic lights or in bumper to bumper traffic. Battery light comes on when stalls, put in park and shut car off, restart and it is fine until the next stalls. I went back to the battery shop and they said cables and everything is tight, but might be a code that is not showing up yet. I have read a few suggestions on line and some are saying many different things including fuel pump, alternator or ECU. I feel like its something simple. Any help will be appreciated.

1 Reply

CARADIODOC

MECHANIC
33,743 POSTS

I have never heard of this on a Mazda, but it is real common on Chrysler products. When you do not use a memory saver device when replacing the battery, or the battery runs dead, the Engine Computer loses it memory. Fuel trim numbers start to be relearned as soon as you start driving, but the Engine Computer needs to relearn "minimum throttle" before it will know when it must be in control of idle speed. Until then, you might need to hold the accelerator pedal down 1/4" to get the engine to start, you wont get the nice "idle flare-up" to 1500 rpm's at engine start-up, and it will tend to stall at stop signs. To meet the conditions for the relearn to take place on Chrysler products, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the pedals.

You can try that procedure with your car, but if it does not work, visit the dealer and ask one of the mechanics what must be done for the relearn to occur. It should include some variation of normal driving conditions.