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P0375 — Timing Reference High Resolution Signal B

Generic OBD-II · all makesPowertrain (engine & transmission)

P0375 indicates that the powertrain control module (PCM) has detected a problem with the high-resolution timing reference signal B, typically supplied by the crankshaft position sensor. This signal is critical for precise ignition timing and fuel injection control. A fault in this circuit can prevent the engine from starting or cause severe drivability issues.

Symptoms

What causes it — most likely first

1. Failed crankshaft position sensor (high-resolution signal circuit)

The sensor itself may have an internal open, short, or degraded output, causing loss of the high-resolution signal.

2. Damaged or corroded wiring/connectors in the sensor circuit

Broken wires, chafed insulation, or corroded terminals can interrupt the signal between the sensor and PCM.

3. Damaged reluctor wheel (tone ring) on the crankshaft

Missing or damaged teeth on the reluctor wheel prevent the sensor from generating a proper high-resolution pattern.

4. Excessive air gap between sensor and reluctor wheel

Incorrect sensor installation or mounting bracket distortion can increase the air gap beyond specification, weakening the signal.

5. PCM internal fault (rare)

An internal PCM driver or processing error for the high-resolution signal input is possible but uncommon; verify all other causes first.

How it's diagnosed

  1. Retrieve all stored codes and freeze frame data; note any related crankshaft or camshaft position sensor codes.
  2. Visually inspect the crankshaft position sensor wiring harness and connector for damage, corrosion, or loose terminals.
  3. Measure the sensor’s resistance and compare to manufacturer specifications; replace if out of range.
  4. Use an oscilloscope to observe the high-resolution signal pattern while cranking; look for missing pulses, noise, or incorrect amplitude.
  5. Check the reluctor wheel for physical damage, missing teeth, or excessive runout if the signal is abnormal.
  6. Verify sensor mounting and air gap per service information; adjust or reinstall if necessary.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationSAE generic — identical on every make
Related codesP0370 — Timing Reference High Resolution SignaP0371 — Timing Reference High Resolution SignaP0372 — Timing Reference High Resolution SignaP0373 — Timing Reference High Resolution SignaP0374 — Timing Reference High Resolution SignaP0376 — Timing Reference High Resolution Signa

Frequently asked

Is the PCM likely to be the cause of P0375?

No. The PCM is rarely the root cause; the crankshaft position sensor, its wiring, or the reluctor wheel are far more common. Replace the PCM only after all other causes have been ruled out with proper testing.

Can a bad camshaft position sensor cause P0375?

P0375 specifically references the high-resolution signal B, which is typically the crankshaft position sensor. A camshaft sensor fault would usually set a different code (e.g., P0340).

Will the vehicle run with P0375 active?

In most cases the engine will not start or will stall immediately because the PCM cannot synchronize ignition and injection without the high-resolution signal.

How critical is the air gap between the sensor and reluctor wheel?

An excessive air gap can weaken the signal enough to trigger P0375. The gap must be within the manufacturer’s specified range for reliable operation.