PATS Ignition Key Transponder Signal Is Not Received
Your car's security system isn't detecting the unique signal from your key's transponder chip, like a store's security gate not recognizing your access card. Without this signal, the engine won't start as a theft-prevention measure.
The PATS (Passive Anti-Theft System) receiver coil in the steering column reads the radio frequency signal broadcast by the transponder chip inside the key. The ECM expects to receive a valid code within 0.5 seconds of ignition activation; if no valid signal is detected, the immobilizer locks the fuel injectors and ignition.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Transponder Signal Strength | Signal detected and verified within 500ms | No signal or invalid code after 500ms timeout |
| Signal Frequency Match | 125 kHz RF signal matches programmed key code | Frequency mismatch or corrupted code data |
Code B1600 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, B1600 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.