P0376 code definition
The P0376 code means that your vehicle’s PCM has detected an irregularity with the high resolution timing reference signal.
What the P0376 code means
The optical sensor gives a high-resolution signal to your vehicle’s PCM by tracking pulses on the sensor disk, a component located near the injection pump. This signal is extremely important because it aids the PCM with fuel timing and overall control. One way the PCM keeps track of this is by monitoring the number of high-res pulses missed.
This high resolution timing reference signal of your vehicle was designed to function within certain parameters. If it exceeds this predetermined amount of degrees, the PCM will detect this variation and store the P0376 code. A Check Engine light should come on too. The “B” is a reference to an area of the system’s circuitry. It is not meant to pertain to a particular component.
Every make and model has its own maximum allowable amount of degrees that are considered acceptable. Even the transmission and engine size/type matters where this number is concerned.
What causes the P0376 code?
There are a number of things that could be responsible for this code being stored, some more likely than others. Those that are most likely would include:
- A defective camshaft
- A defective crankshaft
- Defective distributor position sensors
If none of those problems are the ones that caused the code, likely candidates would be:
Mechanical distributor breakdown (especially common in rear-wheel drive vehicles with high mileage)
Wiring and other electrical components that have are faulty, damaged or otherwise corroded
Finally, although extremely rare, it is possible that P0376 gets stored only because the PCM is faulty.
What are the symptoms of the P0376 code?
Unfortunately, the symptoms that accompany this code are both numerous and diverse, meaning it can be difficult for those who don’t own a scanner.
For example, some drivers will notice no symptoms at all aside from the Check Engine light. Others will immediately notice their engine misfire. Still other drivers will have to put up with spark knock when they accelerate, meaning their fuel detonates erratically, causing an audible effect and usually wasting gas.
Other conditions related to P0376 may also lead to lowered fuel efficiency. Even though the symptoms can be quite severe, some models require multiple failure cycles before the Check Engine light will come on.
How does a mechanic diagnose the P0376 code?
Your mechanic will need a scanner to diagnose the underlying problem. They may also watch the tachometer as your vehicle is cranked with the starter or allowed to run (this will depend on the CPS design).
If there isn’t an RPM signal, the mechanic will need to examine the crankshaft gear, sensor connector and crankshaft position sensor for signs of damage and whether or not repairs are necessary.
After that, an oscilloscope can be used to test the vehicle’s CPS signal wire for sufficient waveforms per each engine resolution.
Common mistakes when diagnosing the P0376 code
As the code can be triggered by so many different causes, stopping short of a full diagnosis is a common mistake that can easily cause unnecessary or incorrect repairs/replacements. The camshaft and crankshaft are often mistakenly replaced because of this.
How serious is the P0376 code?
The P0376 code is definitely something that should be repaired right away. At the very least, you’re not getting the MPG you should. However, the aforementioned problems could cause damage too.
What repairs can fix the P0376 code?
There are a handful of ways your mechanic may proceed:
- Repairing/replacing the crankshaft position sensor, crankshaft gear and/or sensor connector
- Repair or replace open or shorted wiring
- Repair or replace connectors
Additional comments for consideration regarding the P0376 code
Even if the Check Engine Light doesn’t come on, strange sounds coming from your engine that often accompany P0376 should be enough to consider a visit from a qualified mechanic.
Need help with a P0376 code?
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