PATS Received Incorrect Key-Code From Ignition Key Transponder
Your car's security system detected that your key's embedded chip is sending the wrong code, like trying to unlock a door with a key that has a corrupted pattern. The engine won't start until the vehicle recognizes a valid key.
The PATS (Passive Anti-Theft System) module reads the transponder ID code transmitted by the ignition key when turned to ON position. The ECU compares this received code against programmed valid key codes stored in memory. If the code does not match or is corrupted, the fuel pump relay and injectors are disabled.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Transponder Code Match | Received code matches stored key profile | Code mismatch or no signal received from transponder |
| Signal Strength | Transponder signal detected within normal range | Weak or corrupted transponder signal below threshold |
Code B1601 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.
Once the fault is repaired, B1601 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.