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P0373 OBD-II Trouble Code: Timing Reference High Resolution Signal A Intermittent/Erratic Pulses

Check Engine Light

What the P0373 code means

A P0373 means that your powertrain control module (PCM) has detected an irregularity in the high resolution timing reference signal. The “A” refers the area of the system circuitry than to a particular component in your vehicle. If the PCM detects variations in the high-resolution engine timing signal that exceed a set number of degrees, the P0373 code will be stored and your Service Engine Soon lamp will come on.

What causes the P0373 code?

Some causes are more popular than others. The most common causes for the P0373 code are defective crankshaft, camshaft, and distributor position sensors. The next most common is mechanical distributor failure, which occurs often in high-mileage rear-wheel drive domestic applications. Faulty, corroded, or damaged wiring and electrical connectors may also cause this code to appear. PCM failure is a possibility but highly unlikely.

What are the symptoms of the P0373 code?

There are a few symptoms for this code. Some are undetectable while others include an engine misfire. You may also notice a decrease in fuel mileage. But please note that it may take a while before your service engine light comes on, so it is important to recognize these other symptoms ahead of time.

How does a mechanic diagnose the P0373 code?

A good starting place for receiving a successful diagnosis of the crankshaft position sensor is to check for an engine RPM signal when the engine is cranked or running. You can do this using a scanner or simply by observing your vehicle’s tachometer as your engine is running. If you do not detect an RPM signal, then you should visually inspect the crankshaft position sensor, crankshaft gear, and sensor connector for damage and signs of repair. If you do not see any obvious signs of damage, then you should test the CPS system for a reference voltage signal (typically five-volts). If your system voltage readings do not match up with your manufacturer’s specified reference figures, you will need to check for system continuity using your digital volt/ohmmeter. But be careful when checking resistance values in wiring that is connected to the PCM. To ensure safety, disconnect the electrical connector from the PCM before using your ohmmeter on the harness side of the circuit.

Common mistakes when diagnosing the P0373 code

Common mistakes include replacing your vehicle’s camshaft, crankshaft, and distributor sensors, which will probably not solve your problem. Crank and cam reluctor rings need to be tested whenever your replace sensors. Also, make sure that if you are replacing your crankshaft or camshaft sensors that you replace them as a set, and not individually.

How serious is a P0373

A P0373 is serious and, in most cases, should be examined by a trained technician. Not only is a P0373 a serious issue but it is also difficult to fix, requiring expensive and specialized diagnostic tools. If you do not have these tools, you will want to see a professional technician and have him or her determine just what is wrong with your vehicle.

What repairs can fix the P0373 code?

If system reference voltage readings match up with specified values, you will need to replace the camshaft sensor, distributor hall-effect sensor, and the crankshaft sensor. Inspect your distributor for excessive side-to-side wobble and endplay. If the distributor is broken or worn out, you will need to replace it and retest the system for failures.

Additional comments for consideration regarding the P0373 code

A P0373 can be a complicated issue to solve. It may require that you replace several components, which is time consuming and frustrating if you do not have the proper training and tools. If you are thinking of doing this on your own, you might want to contact a trained technician to ask questions about the best way to solve your problem.

Need help with a P0373 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and [book an appointment online}(https://www.yourmechanic.com/services/check-engine-light-is-on-inspection) or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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