Ignition Tach Circuit Failure
The engine control computer can't read the tachometer signal properly, like a speedometer that stops working. This usually means a wiring issue or failed sensor between the ignition system and the dashboard.
The ECU monitors the ignition/tach signal from the distributor, coil pack, or crank sensor to determine engine RPM. It expects a consistent pulsing voltage signal that correlates to combustion events. If the signal is absent, too weak, or unstable, the ECU logs a circuit failure.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Tach Signal Voltage | 0.5–5V pulsing at engine RPM rate | No signal, constant voltage, or voltage below 0.2V |
| Signal Frequency | Proportional to engine RPM (e.g., 20–150 Hz at idle to 6000 RPM) | No pulses detected or frequency mismatch for >2 seconds |
Code B1367 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, B1367 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.