P0373 — Timing Reference High Resolution Signal « A » Intermittent/Erratic

Introduction:
The diagnostic trouble code (DTC) P0373 indicates an issue with the vehicle’s engine timing reference signal, specifically related to an irregular or interrupted high-resolution timing signal. This code often points to an inconsistency in the timing system, which can affect engine performance. It’s important to note that labels and exact wording used for this code may vary slightly between different vehicle manufacturers.

Fast Facts

System affected: Engine Timing System
Severity: Moderate to High
Main symptoms: Rough running, hesitation, misfire, engine stalling
Driveability: Limited — potential for reduced performance or stalling

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Manufacturer variations for trouble code P0373

Different vehicle manufacturers may assign different labels or code descriptions that relate directly to the same or similar underlying issue. These variations can depend on the OEM (Original Equipment Manufacturer) and the specific engine control system used.

Ford: P0373 — Timing Reference High Resolution Signal « A » Intermittent
Hyundai/Kia: P0373 — Camshaft Position Sensor « A » — Signal Intermittent
Mazda: P0373 — Timing Signal Intermittent/Erratic
Volkswagen/Audi: P0373 — Timing Reference Signal Intermittent
Other OEMs: Similar codes with slight variations in naming or description, but all relating to irregular timing signals.

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What does trouble code P0373 mean?

This code fundamentally indicates that the vehicle’s engine control unit (ECU) is detecting an **intermittent or erratic high-resolution timing reference signal**. This timing reference is essential for synchronising fuel injection and ignition timing precisely.

The ECU continuously monitors the signal from specific sensors or components associated with the engine’s timing system, such as camshaft or crankshaft sensors. When it notices irregularities—like inconsistent voltage, missing signals, or fluctuations—it triggers this diagnostic trouble code.

**Typically**, this code appears in scenarios where the signal is suddenly interrupted, unstable, or shows inconsistent timing, potentially due to wiring issues, sensor faults, or mechanical problems.

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Severity and risks of trouble code P0373

While not necessarily dangerous in all circumstances, P0373 can lead to **significant engine performance issues** if left unaddressed. The risks include poor engine timing, misfires, rough running, increased emissions, and potential stalling. The severity depends largely on the root cause—some issues may be minor electrical faults, while others could point to more serious mechanical failures.

**Can the vehicle be driven?**
– Limited — the vehicle can typically still be driven, but with caution.
– It’s advisable to address the issue promptly to avoid further damage or breakdown.

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Symptoms of trouble code P0373

The appearance of P0373 often results in noticeable changes in engine operation. Drivers may experience a variety of symptoms, including:

– Engine **hesitation or misfire** during acceleration
– **Rough idling** or uneven engine operation
– Loss of power or **stuttering** when driving
– **Engine stalling**, especially at idle or low speeds
– Decreased fuel efficiency
– Visible **diagnostic trouble code** on an OBD-II scanner

These symptoms can sometimes be subtle, particularly if the issue is intermittent, making proper diagnosis essential.

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Most likely causes of trouble code P0373

Trouble code P0373 can be caused by a variety of issues, ranging from electrical faults to mechanical problems. Here’s a ranked list of the most common causes based on typical vehicle diagnostics:

Damaged or faulty camshaft or crankshaft position sensors — These sensors generate the timing signals. A failure or contamination (like oil or debris) can cause intermittent signals.
Wiring harness faults or poor electrical connections — Loose, corroded, or damaged wiring to sensors or the ECU can intermittently disrupt the signal.
Issues with the ECU or internal control modules — Rare, but possible when the electronic control unit malfunctions or has software issues.
Mechanical timing issues — Such as a worn timing chain or belt, misaligned sprockets, or timing gear problems that impact the signal integrity.
Interference or electromagnetic disturbances — External electromagnetic interference may affect sensor signals in some cases.

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How to diagnose trouble code P0373

Diagnosing P0373 requires a systematic approach, combining visual inspections and live data analysis. Here are generic, safe steps to identify the root cause:

Check for related codes — Always scan for other DTCs that may pinpoint specific component failures.
Inspect sensor wiring and connectors — Look for corrosion, damage, or loose connections at the camshaft and crankshaft sensors.
Test the sensor signals — Use an oscilloscope or a multimeter (if equipped with appropriate functions) to verify the sensor output during engine run.
Check sensor operation and replace if faulty — Swap suspect sensors temporarily with known good ones to see if the code clears.
Inspect timing components — Examine timing chains, belts, or gears for wear or misalignment.
Examine wiring harnesses — Ensure wiring is secure, free of damage, and properly grounded.
Update ECU software — If applicable, check for and install any OEM-recommended updates.

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Possible repairs for trouble code P0373

The appropriate repair depends on the root cause identified during diagnosis. Generally, repairs include:

Replacing faulty sensors — Camshaft or crankshaft position sensors that show signs of failure. This is a basic repair suitable for DIY or professional technicians.
Repairing or replacing wiring and connectors — Address corrosion, damage, or poor connections to restore proper signal transmission. Usually a professional repair.
Timing system adjustments or replacements — Correcting timing chain or belt issues, including realignment or replacement, which often requires a professional due to complexity.
Updating or reprogramming the ECU — As recommended by the OEM, often performed at a dealership or specialised garage.
Electrical system overhaul — Ensuring electromagnetic stability and shielding if interference is suspected.

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Vehicles commonly associated with trouble code P0373 in Europe

This code can occur in various makes and models, especially those with aggressive or complex timing systems. In Europe, it’s more prevalent across brands that utilize similar timing sensor setups and electronic control strategies. Examples include:

Volkswagen Group (VW, Audi, SEAT, Škoda):

– Commonly found in models equipped with direct injection engines and advanced timing systems.

Ford:

– Particularly in petrol engines with variable valve timing.

Hyundai/Kia:

– In engines with intricate camshaft timing sensors.

Mazda:

– On models with variable valve timing systems.

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Frequent mistakes with trouble code P0373

Diagnosing and repairing P0373 can be straightforward, but some common errors can complicate resolution:

Assuming sensor failure without visual verification — Always inspect wiring and connections first.
Ignoring related or stored codes — Other codes can provide valuable clues.
Replacing sensors without proper testing — Not all sensor faults show obvious physical damage.
Overlooking mechanical timing issues — Electrical testing alone cannot find mechanical causes.
Failing to clear codes after repairs — Remember to erase DTCs and verify that the condition no longer exists.

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FAQ — trouble code P0373

Can this code disappear on its own?

While some intermittent issues may resolve temporarily, P0373 generally requires diagnosis and repair. It’s unlikely to disappear completely without intervention, especially if the root cause remains present.

Can I keep driving?

It’s possible to drive with this code, but caution is advised. Limited driveability and potential engine roughness can occur. Prolonged driving without repair risks further damage.

Why does the code return after clearing it?

The code reappears typically because the underlying fault, such as a failing sensor, wiring issue, or mechanical timing problem, is unresolved. Clearing DTCs only temporarily resets the system, not fixing the root cause.