P0373 — Timing Reference High Resolution Signal A Intermittent/Erratic Pulses

What does P0373 specifically mean?

P0373 means the ECU detected intermittent or erratic high-resolution timing-reference pulses, generally from the crankshaft-position sensor circuit. The controller can briefly lose crank-speed and timing synchronization when those pulses drop out.

What is the most common cause of P0373?

The most frequent cause is a poor connection, damaged terminal, or chafed wire in the crankshaft-position sensor high-resolution circuit. A failing sensor, incorrect air gap, or damaged reluctor wheel can produce the same intermittent code.

Can I drive the vehicle with P0373 stored?

Driving is possible if the engine runs smoothly, but P0373 can cause an abrupt stall or no-start. Keep any trip short, avoid heavy traffic when possible, and stop driving immediately if the engine surges, loses power, or stalls.

Do I need to replace the crankshaft position sensor for P0373?

Not automatically. First inspect and waveform-test the complete circuit, connector, power, ground, reluctor wheel, and sensor gap. Replace the sensor only when testing shows that it is generating the missing or erratic high-resolution pulses.

When the Engine Control Unit detects an abnormal pattern in the high-resolution timing reference signal circuit, it logs OBD2 code P0373. This specific fault is officially described as "Timing Reference High Resolution Signal A Intermittent/Erratic Pulses," which points to a problem where the signal that helps the ECU precisely track crankshaft position becomes unstable or unpredictable. The PCM relies on this high-resolution signal to synchronize fuel injection and ignition timing with extreme accuracy, especially during high-RPM operation when even minor timing errors can cause drivability problems.

The control module watches this signal circuit constantly while the engine is running. P0373 gets stored in memory only after the fault persists long enough to exceed the threshold across a predetermined number of drive cycles. When this happens, the PCM also captures freeze frame data—essentially a snapshot of critical operating parameters like engine speed, load, coolant temperature, and vehicle speed at the exact moment the irregularity occurred. That recorded information is invaluable when you start troubleshooting because it shows you exactly what conditions triggered the code.

The malfunction indicator lamp (MIL) turns on once P0373 is confirmed, alerting the driver that a problem exists in a system the vehicle can typically still manage in a limited capacity. How severely drivability is affected depends entirely on which component in the timing reference circuit is at fault and whether the ECU can compensate using alternative data.

Symptoms of P0373

• The Check Engine Light stays illuminated on the dashboard
• The affected system operates intermittently or fails entirely during the drive
• Fuel economy drops noticeably in some vehicles
• The engine may enter a reduced-power limp mode, depending on which component is involved
• Engine performance feels rough or unstable, particularly under load
• In rare cases, the vehicle may stall or struggle to restart

Common Causes

• Corroded, loose, or physically damaged electrical connector in the circuit
• Open or shorted wiring somewhere along the high-resolution signal harness
• A blown fuse that interrupts power or ground to the affected circuit
• An inadequate ground connection causing intermittent signal loss
• Failure of the crankshaft position sensor or related actuator sending the signal
• An internal driver fault inside the PCM itself, though this is the least common culprit

How to Diagnose P0373

1. Plug in an OBD2 scanner, retrieve P0373, and record the freeze frame data—this tells you engine rpm, load, temperature, and speed when the fault first appeared.
2. Look for any related diagnostic trouble codes that may point to the root cause, and search manufacturer TSB databases using your VIN for known software updates or factory fixes.
3. Perform a hands-on inspection of the wiring harness and connectors tied to the timing reference signal circuit, looking for chafing, corrosion, bent pins, or loose seats.
4. Use a multimeter to verify reference voltage, ground integrity, and signal continuity at the sensor or actuator connector.
5. Conduct a wiggle test on the harness while monitoring live data—any signal dropouts or interruptions reveal broken wires inside the insulation.
6. Clear the code after inspection, then drive the vehicle through the freeze frame conditions and verify P0373 does not reappear.

Repair Options and Costs

Tackle the least expensive and most likely problems before replacing major components. Wiring harness repair or connector replacement typically runs $80–$250 depending on accessibility and labor time. If the sensor or actuator itself is defective, a replacement part plus installation generally costs $150–$500 depending on vehicle make and part source. In the unlikely event the control module's internal driver has failed, PCM repair or replacement can cost $300–$1,000 including programming.

Total Cost to Fix P0373

Overall, addressing P0373 typically ranges from $80 to $1,000 depending on what component is actually at fault. The vast majority of cases involve wiring or connector issues rather than an expensive control module. Spending time on proper diagnosis before purchasing parts is the smartest move—the worst-case scenario is rarely the first thing to check.

Can You Drive with P0373?

In most vehicles, P0373 does not immediately strand you. The car usually remains drivable, though you may notice reduced performance, a disabled辅助系统, or occasional stuttering. Treat this as a priority repair if the engine stalls, refuses to start, or if any brake or steering warnings appear alongside the code.

Related OBD2 Codes

• P0300: Random/Multiple Cylinder Misfire Detected
• P0301: Cylinder 1 Misfire Detected
• P0302: Cylinder 2 Misfire Detected
• P0303: Cylinder 3 Misfire Detected
• P0304: Cylinder 4 Misfire Detected
• P0305: Cylinder 5 Misfire Detected