P0375 Timing Reference High Resolution Signal B Malfunction

P0375 indicates a malfunction in Timing Reference High Resolution Signal B. The controller is not receiving the expected secondary high-resolution timing reference.

Code details

Generic OBD-II · P0

System: Ignition / Misfire
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not assume signal A is the problem when the code specifically identifies the high-resolution B reference path.

Symptoms of P0375

Rough idle, shaking, or a stumble under acceleration.
A flashing check-engine light during an active misfire.
Power loss and higher fuel consumption.

Common causes of P0375

Worn spark plugs, ignition coils, or plug wires.
Fuel-delivery problems — injectors, pressure, or a lean/rich mixture.
Vacuum leaks, low compression, or a mechanical fault in that cylinder.

Useful checks before replacing parts

Compare timing reference signal B with signal A, crank sensor data, cam sync, RPM stability, freeze-frame RPM, and related timing reference codes.
Inspect sensor power, ground, signal wiring, shielding, connector condition, trigger wheel or optical track condition, and module input pins.
Scope signal B during cranking and running to confirm waveform shape, amplitude, pulse spacing, and dropouts.

Related OBD-II codes

These nearby ignition / misfire entries can help compare wording and pin down the fault area.