Exception in rendering!

Message: window is not defined

ReferenceError: window is not defined
    at new c (/tmp/execjs20161209-55387-1d9lzqkjs:136:3912)
    at m.mountComponent (/tmp/execjs20161209-55387-1d9lzqkjs:47:15602)
    at /tmp/execjs20161209-55387-1d9lzqkjs:49:31860
    at a.r.perform (/tmp/execjs20161209-55387-1d9lzqkjs:47:12503)
    at Object.a [as renderToString] (/tmp/execjs20161209-55387-1d9lzqkjs:49:31821)
    at r (/tmp/execjs20161209-55387-1d9lzqkjs:50:21164)
    at Object.S.ReactOnRails.serverRenderReactComponent (/tmp/execjs20161209-55387-1d9lzqkjs:32:6073)
    at eval (eval at <anonymous> (/tmp/execjs20161209-55387-1d9lzqkjs:173:8), <anonymous>:10:23)
    at eval (eval at <anonymous> (/tmp/execjs20161209-55387-1d9lzqkjs:173:8), <anonymous>:17:3)
    at /tmp/execjs20161209-55387-1d9lzqkjs:173:8

P0378 OBD-II Trouble Code: Timing Reference High Resolution Signal B Intermittent/Erratic Pulses

Check Engine Light

P0378 code definition

If the PCM has stored the code P0378, it means that the system has detected an abnormal pulse reading from the high resolution timing reference signal B, which indicates that there is a fault with the system’s circuitry.

What the P0378 code means

Located in the injection pump is a sensor disk that emits pulses that the PCM uses to control fuel injection timing. The PCM tests for missed pulses, and compares those to the number of pulses it should be detecting according to the manufacturer. If this value is not correct or erratic, the PCM will store the code P0378.

What causes the P0378 code?

There are many things that could cause an erratic pulse reading between the sensor disk and the PCM. Most often, these include a defective crankshaft, camshaft, or distributor position sensors.

However, other causes may include:

  • Failure of the distributor
  • Open or shorted optical sensor
  • Faulty, corroded, damaged, open, or shorted wiring or connectors
  • Failed PCM, in rare cases

What are the symptoms of the P0378 code?

The P0378 code could be preceded by no symptoms at all besides the illumination of the Check Engine light. However, it could also be preceded by engine misfiring, knocking when accelerating, and decreased fuel economy.

How does a mechanic diagnose the P0378 code?

A mechanic should first abstract code information from the PCM with an OBD-II scanner, and check for other codes that may indicate a larger or related issue.

In order to diagnose the cause of the P0378 code, many mechanics begin by inspecting the crankshaft gear and crankshaft position sensor. This is accomplished by checking for the engine RPM signal while the engine is running. If there is no signal detected, then a visual inspection of the crankshaft and related components is necessary. The technician should repair or replace any components that are faulty. This process eliminates one of the most common issues for the P0378 code, and may help narrow the options for following repairs.

Common mistakes when diagnosing the P0378 code

When diagnosing the P0378 code, a common mistake is forgetting to clear the code and do a road test after performing each potential solution. This step should be done after each repair, to help narrow down the cause faster. By replicating the moment of failure, a mechanic may be able to discover the problem much faster.

Another common mistake with the P0378 code is automatically replacing the crankshaft, camshaft, or distributor sensors, rather than checking for mechanical distributor failure or other issues. Additionally, it is important to replace crankshaft or camshaft sensors as a set, rather than individually.

How serious is the P0378 code?

Because the P0378 code relates directly to how the PCM controls fuel injection and timing, this is a very serious issue that should be addressed immediately. Failure to address this issue when it is detected could result in the failure of other engine components when they aren’t able to obtain fuel, or correct fuel pressure.

What repairs can fix the P0378 code?

In order to address a P0378 code, there are a few repairs that a mechanic may choose to perform. These include:

In the rare case that the PCM is faulty, the mechanic may replace the PCM.

Need help with a P0378 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 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
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Post a question and get free advice from our certified mechanics.

ASK A QUESTION

More related articles

How Long Does a Fuel Filler Neck Last?
Getting gas from the pump to your gas tank is the only way to keep a car going. The fuel filler neck is a metal tube that is welded to the...
How Long Does a Vacuum Brake Booster Check Valve Last?
The braking system on your car requires a lot of pressure. The vacuum booster is one of the main sources of this pressure. This booster will take the pressure that...
How Long Does a Throttle Return Spring Last?
Not all vehicles on the road feature an electronic throttle control (ETC), which is also called drive-by-wire. For vehicles that don't offer this system, they have a throttle cable instead that...


Related questions

Q: Car loses power and stalls - 2014 Cadillac ATS

Hi! You may have to leave your vehicle with the dealership in order for them to be able to duplicate the concern. While it is not necessary for there to be diagnostic trouble codes present in the vehicle's computer in...

Q: Car is shaking violently

Since you have listed a number of issues, there is no certain way to provide you with a definitive answer. It's highly unlikely that all your issues are rooted in one part or system. If the plugs are covered in...

Q: Car won't accelerate past 3000rpm

This issue could be caused by a variety of things. I would suggest by checking to be sure that the idle air control module is working properly. Also, check to be sure that the throttle body is delivering...