Secret Codes guide
**042*0000*1234*1234# on iPhone: Change Your SIM PIN2
By Muhammad Shahid · · 4 min read
Quick answer
**042*0000*1234*1234#: Change the second SIM PIN that guards fixed dialling and similar features. PIN2 is a separate credential on the SIM that protects a different set of functions from the ordinary PIN. Historically it gates fixed dialling numbers, advice of charge counters and a handful of other stored settings. TS 22. 030 section 6. 6. 2 gives the procedure as **042*OLD_PIN2*NEW_PIN2*NEW_PIN2#.
Secret CodesDial codes, SIM & network test · Free on the App StoreDownload free →| Code | **042*0000*1234*1234# |
|---|---|
| What it does | Change the second SIM PIN that guards fixed dialling and similar features. |
| Published for | AT&T, T-Mobile and any iPhone |
| Type | Support varies |
Change the second SIM PIN that guards fixed dialling and similar features. This page explains what **042*0000*1234*1234# does, how to use it on an iPhone and which carriers it applies to.
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What does **042*0000*1234*1234# do?
PIN2 is a separate credential on the SIM that protects a different set of functions from the ordinary PIN. Historically it gates fixed dialling numbers, advice of charge counters and a handful of other stored settings. TS 22.030 section 6.6.2 gives the procedure as **042*OLD_PIN2*NEW_PIN2*NEW_PIN2#.
Like the PIN change, this is a conversation between the handset and the SIM card and never reaches the carrier network.
iPhone exposes no user interface for PIN2 and no interface for the features it protects, so for most iPhone owners this is documentation rather than a tool. It is listed because a SIM moved into an iPhone from another device may still carry a PIN2 that matters if the SIM is moved on again.
Important: Three wrong PIN2 entries block PIN2 and it can only be restored with the separate PUK2 from your carrier. Do not guess it.
How do I use **042*0000*1234*1234#?
- Open the Phone app and tap Keypad.
- Type **042*0000*1234*1234# exactly as written.
- Press the green Call button and wait for the result.
Which carriers does this apply to?
| Published for | AT&T, T-Mobile and any iPhone |
|---|---|
| Type | Support varies |
| Good to know | iPhone provides no PIN2 interface and generally will not process this string. Included because the credential genuinely exists on the SIM and matters on other handsets. |
Related call barring and sim pin codes
- **04*0000*1234*1234#: Change Your SIM PIN
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- #43*11#: Turn Off Call Waiting for Voice Only
- **052*12345678*1234*1234#: Unblock PIN2 With the PUK2
- *43*11#: Turn On Call Waiting for Voice Only
- *#591#: Check Multiple Subscriber Profile
See all call barring and sim pin codes or every category of iPhone codes.
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Frequently asked questions
What does **042*0000*1234*1234# do on iPhone?
Change the second SIM PIN that guards fixed dialling and similar features. PIN2 is a separate credential on the SIM that protects a different set of functions from the ordinary PIN. Historically it gates fixed dialling numbers, advice of charge counters and a handful of other stored settings. TS 22.
What else should I know about **042*0000*1234*1234#?
030 section 6. 6. 2 gives the procedure as **042*OLD_PIN2*NEW_PIN2*NEW_PIN2#. Like the PIN change, this is a conversation between the handset and the SIM card and never reaches the carrier network.
What are the steps for **042*0000*1234*1234#?
1. Open the Phone app and tap Keypad. 2. Type **042*0000*1234*1234# exactly as written. 3. Press the green Call button and wait for the result.
Where do I use **042*0000*1234*1234#?
On the keypad of the Phone app.
Do I need to press Call after typing **042*0000*1234*1234#?
Yes. Type it on the Phone keypad, then press the green Call button.
Is **042*0000*1234*1234# a hidden or secret code?
No. It is a published service, not a hidden menu. iPhones do not have Android-style engineering menus.
Which carriers does **042*0000*1234*1234# work on?
It is published for AT&T, T-Mobile and any iPhone. iPhone provides no PIN2 interface and generally will not process this string. Included because the credential genuinely exists on the SIM and matters on other handsets.
Is there anything to watch out for with **042*0000*1234*1234#?
Three wrong PIN2 entries block PIN2 and it can only be restored with the separate PUK2 from your carrier. Do not guess it.
Does **042*0000*1234*1234# work on Android phones too?
It is handled by the carrier or service rather than the iPhone, so it is not tied to one phone brand. Check with your carrier.
Will **042*0000*1234*1234# work outside the US?
It is published for US carriers and services, so do not count on it abroad. Ask your carrier before you travel.
What if **042*0000*1234*1234# does not work on my iPhone?
Check that it applies to your carrier first, because carriers decide which services they offer and can change them. If it should apply to your line, contact your carrier.
What is related to **042*0000*1234*1234#?
**04*0000*1234*1234#: Change Your SIM PIN. Replace the PIN that unlocks your SIM at startup.
Sources
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