SAN DIEGO (CBS / AP) — Wal-Mart has agreed to pay a penalty of $2.1 million for charging California costumers at prices higher than those posted, in violation of a 2008 judgment ordering the retail chain to stop.

State Attorney General Kamala Harris said Wednesday that Wal-Mart has agreed to pay the penalty after an investigation found that stores in 11 counties made checkout scanning errors that left customers paying more than listed prices.

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The investigation was a follow-up to the 2008 judgment, where 164 stores in 30 counties were found to have overcharged customers.

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Wal-Mart agreed at the time to knock $3 off the lowest listed price of an item for any customer who was overcharged. That program, set to expire later this year, will now be extended to November 2013.

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