1. Home
  2. /
  3. Complete List of OBD2...
  4. /
  5. P0373 Code – What...

P0373 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


P0373 is a diagnostic trouble code (DTC) that relates to the specific problem of Time Reference High-Resolution Signal “A” with Too Many Pulses. This code is part of an OBD II system used in modern vehicles that monitors and reports problems with different engine components, called OnBoard Diagnostics II.


The P0373 code indicates that the Engine Control Module (ECM) has detected an excessive number of pulses or signals from the Timing Reference High-Resolution Signal “A” circuit. For the ECU to be precise in its timing of ignition and fuel injection, which is crucial for proper engine performance, this signal is essential.


A P0373 code may appear as a result of several circumstances, such as:

  • A crankshaft position sensor that is broken.
  • Timing Reference High-Resolution Signal “A” circuit wiring or connection issues.
  • A crankshaft or camshaft with damage or alignment issues.
  • Problems with the timing chain or belt.
  • Rarely, there are ECM problems.


Common symptoms associated with a P0373 code may include:

  • Illumination of the Check Engine Light (CEL) on the dashboard.
  • Reduced engine performance or power.
  • Poor fuel efficiency.
  • Engine misfires or rough idling.
  • Stalling or difficulty starting the engine.
  • Abnormal engine noise.


A mechanic or technician will often take the following actions to troubleshoot a P0373 code:

  • To get the code and any associated codes, use an OBD-II scanner.
  • Check the wiring and the Timing Reference High-Resolution Signal “A” circuit for any obvious damage.
  • To check if the crankshaft position sensor is working properly, measure its voltage and resistance.
  • Verify the crankshaft and camshaft’s alignment.
  • Check the chain or timing belt for optimum tension and wear.
  • To see whether the problem reappears, clear the code and give it a test run.

Common mistakes

Common mistakes when dealing with a P0373 code include:

  • Replacing the sensor without checking the wiring and connectors for issues.
  • Neglecting to inspect the crankshaft and camshaft alignment.
  • Assuming the code is solely caused by a faulty sensor without considering other potential causes.

How serious is this?

The code P0373 should be dealt with immediately as this may hurt engine performance, lack of fuel efficiency, and possible damage to the engines where these are not resolved. It can lead to a stalling or no start of the engine in some cases. This is a major problem, and it calls for attention.

What repairs can fix the codeS?

repair manuals

Repairs for a P0373 code may include:

  • Replacing the crankshaft position sensor if it’s found to be faulty.
  • Repairing or replacing damaged wiring or connectors in the Timing Reference High-Resolution Signal “A” circuit.
  • Realigning the crankshaft or camshaft if they are found to be misaligned.
  • Addressing any issues with the timing belt or chain, such as tension adjustment or replacement.
  • In rare cases, replacing the ECM if it’s determined to be the source of the problem.

Related codes

Related codes may include:

  • P0369 – Timing Reference High-Resolution Signal “A” Circuit Intermittent.
  • P0370 – Timing Reference High-Resolution Signal “A” Circuit.
  • P0371 – Timing Reference High-Resolution Signal “A” Too Few Pulses.


A DTC P0373 code indicates that a problem with the Timing Reference HighResolution Signal ‘A Circuit’, which can have a significant impact on engine performance and efficiency, has been identified. To avoid damage occurring again and to ensure the proper functioning of a vehicle, prompt diagnosis, and repair are essential. Depending upon the particular cause of the code, these may involve sensor replacement, circuit repair, adjustment of crankshafts or camshafts, and timing components.

P0373 Code – What Does It Mean & How To Fix It