OBD-II Generic Error Code P0378: Timing Reference High Resolution B Intermittent Fix

Medium 1-2 hours Medium Severity Verified June 2026
Summarize with ChatGPTSummarize with ClaudeSummarize with Perplexity Add as Preferred Source on Google
Error Code
P0378
Brand
OBD-II Generic
Product Type
automotive
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
1-2 hours
Error code P0378 indicates that the engine control module (ECM) has detected an intermittent signal from the high-resolution timing reference B sensor. This sensor is crucial for accurate ignition timing and fuel injection. A faulty sensor or wiring issue is the most common cause.
Ad

Tools You'll Need

How to Fix Error Code P0378

  1. Check for Other Codes and Freeze Frame Data

  2. Inspect the Wiring and Connector

    Disconnect the battery before probing wires to avoid short circuits.

  3. Test the Sensor Signal

    Do not crank the engine for extended periods to avoid starter damage.

  4. Replace the Sensor if Necessary

    Use caution when working near moving engine parts. Allow the engine to cool.

  5. Check the ECU Grounds and Power Supply

  6. Perform a Road Test

    Obey all traffic laws during the test drive.

Parts You May Need

High-resolution timing reference B sensor
Check Price on Amazon
High-resolution timing reference B sensor
Check Price on Amazon
High-resolution timing reference B sensor
Check Price on Amazon
High-resolution timing reference B sensor
Check Price on Amazon
Ad

When to Call a Professional

If you have inspected the wiring and replaced the sensor but the code returns, or if you are uncomfortable working with automotive electrical systems, consult a professional mechanic. Advanced diagnostics may require specialized equipment.

Frequently Asked Questions

Can I drive with error code P0378?
It is not recommended to drive with this code for long distances. The vehicle may experience rough running, poor fuel economy, or stalling. Have it diagnosed as soon as possible.
Will clearing the code fix P0378?
Clearing the code will only temporarily turn off the check engine light. Unless the underlying issue (faulty sensor, wiring, etc.) is fixed, the code will return.
How much does it cost to fix error code P0378?
DIY repair costs can range from $30-$100 for a new sensor and tools if needed. Professional repair, including diagnosis, can cost $100-$300 or more.
Is P0378 a serious error?
It is moderate. While it may not cause immediate catastrophic damage, it can affect engine performance and fuel efficiency. Ignoring it could lead to other issues.
What sensors are related to code P0378?
The high-resolution timing reference B sensor is often the crankshaft position sensor or camshaft position sensor on some engines.

Related Error Codes