P0373 Code Meaning and Next Steps

First checks take 10 to 15 minutes for the first checks. No special tools are usually needed for the first checks.

Can you keep driving?

Stop driving if any of these apply

!The engine starts running much worse, stalls, or the warning light flashes.
!The vehicle begins to lose power sharply or misfire badly while the code is active.

If the light is steady and the vehicle still drives normally: Often yes for a short time, but it should not be ignored.

What to check first

Step-by-step checks

1
Safety first
Work with the engine off and cool enough to avoid burns from hot ignition and exhaust parts
2
Free - no tools
Inspect the crank and cam sensor connectors, harnesses, and nearby wiring for looseness or damage
3
Basic tool needed
Check whether the engine starts hard, stalls, or loses power at a specific temperature or speed
4
Basic tool needed
If the code appeared after repair work, confirm sensor seating, gap, and harness routing first
5
Basic tool needed
If scan data is available, compare the timing reference signals before replacing parts

If the code returns

-If the signal changes with harness movement, wiring deserves a closer look than the sensor alone.
-If the code returns after a sensor swap, revisit the connector and reference path before buying another part.
-If the engine still acts up after the electrical checks, mechanical timing or reluctor issues become more important.

Background

What this code means

P0373 is a generic OBD-II cam/crank synchronization or timing reference code.

The ECU is seeing a signal pattern that does not line up with expected engine timing or reference pulses.

A no-start, stall, rough run, or intermittent loss of signal can appear when the ECU cannot trust the timing reference path.

Diagnosis

Common causes

Most common

Sensor signal fault

The cam or crank sensor may be dropping out or reading incorrectly.

Common

Connector or wiring issue

A loose, corroded, or heat-damaged connection can interrupt the signal.

Common

Mechanical timing issue

A slipped belt or chain can move the signal out of sync.

Possible

Reluctor or tone wheel issue

A damaged trigger wheel can make the signal pattern look wrong.

Avoid these mistakes

What not to do

xDo not replace sensors first if the wiring, connector, or mechanical timing side has not been checked.
xDo not ignore drivability changes just because the code sounds like a sensor or circuit problem.

Parts

Parts that may need replacing

PartTypical costNotes

Crankshaft or camshaft sensor$30-$180Relevant when the signal tests poorly and the wiring checks out.

Connector pigtail repair$15-$90Worth checking if the plug or pins are damaged.

Timing belt/chain service part$100-$900Use only when timing evidence supports it.

Related OBD codes

P0370

P0370 usually means the high-resolution timing reference signal A is not behaving correctly.

P0371

P0371 usually means the high-resolution timing reference signal A has too many pulses.

P0372

P0372 usually means the high-resolution timing reference signal A has too few pulses.

Source notes

Generic OBD-II (SAE J1979 / ISO 15031-5). P0373 was expanded around common intermittent timing-reference faults, including connector looseness and harness damage.

This guide is written as a generic multi-make reference, so bulletin history, sensor locations, and repair order can still change by manufacturer and engine family.

This is generic OBD-II guidance and should not override vehicle-specific service information. Exact diagnosis and repair steps vary by make, engine family, and model year.

Last reviewed: 2026-04-10

Reference: Open reference

P0373 - P0373 Usually Means the High-resolution Timing Reference Signal a Is Intermittent or Erratic