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P0372 is a diagnostic trouble code (DTC) for "Timing Reference High Resolution Signal A Too Few Pulses". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $79.99. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
P0372 is the OBD-II trouble code for Timing Reference High Resolution Signal A too few pulses.
The Powertrain Control Module (PCM) provides control and timing for the fuel injection system in part by monitoring signals sent by the optical sensor. This sensor sends a high resolution signal to the PCM indicating how many pulses have been detected on the sensor disk on the injection pump.
There should be about 64 pulses for every cam pulse, and when the number actually detected deviates from this norm, the P0372 or another P0370 series code will store. The letter A simply indicates an area of the involved circuitry rather than a specific component.
Conditions that may cause this Diagnostic Trouble Code (DTC) include:
A faulty camshaft or camshaft sensor
A faulty crankshaft or crankshaft sensor
Bad distributor position sensors
An open or short in the timing reference optical sensor harness
A faulty optical sensor
Loose or damaged connections in the timing reference optical sensor circuitry
Mechanical failure in the distributor (most common in rear-wheel drive, high mileage vehicles)
PCM failure (rare)
Sensor failure is typically the most common cause of this trouble code. Still, a thorough diagnostic investigation should be carried out, as car problems often have more than one cause.
There may be no detectable symptoms at all, or there may be engine misfires, spark knock during acceleration, or decreased fuel efficiency. While the code will likely store upon the first occurrence, it may take some time before the Check Engine light comes on, so it’s important to be aware of any noticeable signs of a problem.
Diagnostic procedure for this code may include:
Verifying that the DTC is stored, and recording the freeze frame data using a scan tool
Clearing any stored codes and then road testing the vehicle to see if they return
Visually observing the tachometer with the engine running to see if there is an RPM signal
Visually inspecting the crankshaft position sensor, crankshaft gear, and connectors and wiring for damage
Testing the Crankshaft Position Sensor (CPS) system to ensure the reference voltage matches specifications
Using an ohmmeter to check for system continuity
If necessary, inspecting the distributor for damage, wobble, or too much end-play
Sometimes the crankshaft, camshaft, and distributor sensors will be replaced unnecessarily when the problem actually lies in a distributor malfunction. Neglecting to test the crank and cam reluctor rings when replacing sensors is also a common oversight.
Any malfunction which interferes with proper fuel injection timing and engine function should be considered serious. Because of the specialized diagnostic and repair tools often required for this type of problem, it’s best to have a qualified technician look at the vehicle as soon as possible.
Possible solutions for this DTC include:
If you decide to tackle the diagnostic process yourself, be sure that you disconnect the wiring connectors from the PCM side before checking resistance values on the harness side. This will prevent damage to the PCM.
When replacing crankshaft or camshaft sensors, be sure to replace them as a set, rather than individually.
The cause of DTC P0372 can be complicated and time-consuming to track down and repair. The task may involve multiple repairs, as well as specialized tools and equipment. If you suspect this repair is beyond your skill level, it’s best to contact a qualified mechanic and have them assess the issue instead.
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 or speak to a service advisor at 1-800-701-6230.