Secret Codes guide
**04*0000*1234*1234# on iPhone: Change Your SIM PIN
By Muhammad Shahid · · 4 min read
Quick answer
**04*0000*1234*1234#: Replace the PIN that unlocks your SIM at startup. TS 22. 030 section 6. 6. 2 defines this as **04*OLD_PIN*NEW_PIN*NEW_PIN#. Read the template that way. The first group is your current SIM PIN, the next two are the new PIN entered twice for confirmation.
Secret CodesDial codes, SIM & network test · Free on the App StoreDownload free →| Code | **04*0000*1234*1234# |
|---|---|
| What it does | Replace the PIN that unlocks your SIM at startup. |
| Published for | AT&T, T-Mobile and any iPhone |
| Type | Support varies |
Replace the PIN that unlocks your SIM at startup. This page explains what **04*0000*1234*1234# does, how to use it on an iPhone and which carriers it applies to.
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What does **04*0000*1234*1234# do?
TS 22.030 section 6.6.2 defines this as **04*OLD_PIN*NEW_PIN*NEW_PIN#. Read the template that way. The first group is your current SIM PIN, the next two are the new PIN entered twice for confirmation.
The spec explicitly notes that the send function is not used for this procedure, because it is handled entirely between the handset and the SIM. Nothing is transmitted to the carrier. That is also why it behaves differently from every other string in this file, and why iPhone often will not act on it from the keypad at all.
On iPhone the supported route is Settings, then Cellular, then SIM PIN. On a dual SIM or dual eSIM iPhone you tap the line first. That path does the same job as this code and shows you clearly which line you are changing.
Important: Three consecutive wrong SIM PIN entries block the SIM and it will demand a PUK before it works again. Never guess a PIN. If you have never set one, do not enter a default value you found online, because the carrier default varies and a wrong guess costs you one of your three attempts.
How do I use **04*0000*1234*1234#?
- Open Settings and tap Cellular.
- Tap SIM PIN. On a dual SIM iPhone, tap the line you want first.
- Tap Change PIN, enter the current PIN, then the new PIN twice.
Which carriers does this apply to?
| Published for | AT&T, T-Mobile and any iPhone |
|---|---|
| Type | Support varies |
| Good to know | A handset level procedure rather than a network one. iOS routes SIM PIN management through Settings and does not reliably act on this string from the keypad, so treat the Settings path as the real answer. |
Related call barring and sim pin codes
- #43*11#: Turn Off Call Waiting for Voice Only
- **042*0000*1234*1234#: Change Your SIM PIN2
- *43*11#: Turn On Call Waiting for Voice Only
- **05*12345678*1234*1234#: Unblock a SIM With the PUK
- *#300#: Check Calling Name Presentation
- **052*12345678*1234*1234#: Unblock PIN2 With the PUK2
See all call barring and sim pin codes or every category of iPhone codes.
How Secret Codes helps
Secret Codes keeps this and every other entry a search away. Pick your carrier once and each entry says whether it is published for your line. You can save favourites, add a private note, and record whether a code worked on your line.
Frequently asked questions
What does **04*0000*1234*1234# do on iPhone?
Replace the PIN that unlocks your SIM at startup. TS 22. 030 section 6. 6. 2 defines this as **04*OLD_PIN*NEW_PIN*NEW_PIN#. Read the template that way. The first group is your current SIM PIN, the next two are the new PIN entered twice for confirmation.
What else should I know about **04*0000*1234*1234#?
e spec explicitly notes that the send function is not used for this procedure, because it is handled entirely between the handset and the SIM. Nothing is transmitted to the carrier.
What are the steps for **04*0000*1234*1234#?
1. Open Settings and tap Cellular. 2. Tap SIM PIN. On a dual SIM iPhone, tap the line you want first. 3. Tap Change PIN, enter the current PIN, then the new PIN twice.
Where do I use **04*0000*1234*1234#?
On the keypad of the Phone app.
Do I need to press Call after typing **04*0000*1234*1234#?
Yes. Type it on the Phone keypad, then press the green Call button.
Is **04*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 **04*0000*1234*1234# work on?
It is published for AT&T, T-Mobile and any iPhone. A handset level procedure rather than a network one. iOS routes SIM PIN management through Settings and does not reliably act on this string from the keypad, so treat the Settings path as the real answer.
Is there anything to watch out for with **04*0000*1234*1234#?
Three consecutive wrong SIM PIN entries block the SIM and it will demand a PUK before it works again. Never guess a PIN. If you have never set one, do not enter a default value you found online, because the carrier default varies and a wrong guess costs you one of your three attempts.
Does **04*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 **04*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 **04*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 **04*0000*1234*1234#?
#43*11#: Turn Off Call Waiting for Voice Only. Disable call waiting for voice calls specifically.
Sources
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