Engine-Codes - Generic - P0377

P0377 Code - Timing Reference High Resolution Signal 'B' Too Few Pulses

- Code Popularity: 8,790 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 2/3
Table of contents
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What are the Possible Causes of the DTC P0377?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Timing Reference Optical Sensor harness is open or shorted
  • Timing Reference Optical Sensor circuit poor electrical connection
  • Faulty Timing Reference Optical Sensor
  • Damaged Powertrain Control Module (PCM)
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How to Fix the DTC P0377?

Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the P0377 code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

When is the Code Detected?

Some high resolution pulses are missing from the optical sensor to the PCM

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

What Does the P0377 Code Mean?

The optical sensor provides a high resolution signal to the Powertrain Control Module (PCM) by counting pulses on the sensor disk located in the injection pump. The high resolution is one of the most important inputs by the PCM for fuel control and timing. This test monitors the number of high resolution pulses which have been missed (not detected). It's based on a comparison between the number of pulses that were detected since the last pump cam pulse and the number of the pulses that should have occurred. There are approximately 64 high resolution pulses for every cam pulse.

P0377 Code - Timing Reference High Resolution Signal 'B' Too Few Pulses

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Code P0377 Information for Specific Makes

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