AutoCodes – Mercedes-Benz – P0372 Mercedes-Benz

P0372 Mercedes-Benz Code - Timing Reference High Resolution Signal 'A' Too Few Pulses

Quick Answer

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. Common causes include Timing Reference Optical Sensor harness is open or shorted, Timing Reference Optical Sensor circuit poor electrical connection, Faulty Timing Reference Optical Sensor. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0372 Mercedes-Benz indicates Timing Reference High Resolution Signal 'A' Too Few Pulses.
Common causes: Common causes include Timing Reference Optical Sensor harness is open or shorted, Timing Reference Optical Sensor circuit poor electrical connection, Faulty Timing Reference Optical Sensor.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 3,488

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0372 Mercedes-Benz Description

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.

OBDII Code P0372 Mercedes-Benz - Timing Reference High Resolution Signal 'A' Too Few Pulses - AutoCodes.com — P0372 Mercedes-Benz Code - Timing Reference High Resolution Signal 'A' Too Few Pulses

What does this mean?

What are the Possible Causes of the DTC P0372 Mercedes-Benz?

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)

How to Fix the DTC P0372 Mercedes-Benz?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0372 Mercedes-Benz code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0372 Mercedes-Benz code?

Need more information on how to fix the P0372 Mercedes-Benz code? Get Access to Factory Service Manuals

Need Help with the Code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0372 Mercedes-Benz Code

What does the OBDII code P0372 mean for a Mercedes-Benz?

Code P0372 indicates that the engine control module (ECM) has detected too few pulses from the high-resolution timing reference signal 'A,' which is critical for proper engine timing and performance.

What are the common symptoms of code P0372 in a Mercedes-Benz?

Typical symptoms include rough idling, difficulty starting the engine, reduced engine performance, misfires, or the illumination of the check engine light.

What causes the P0372 code to appear in a Mercedes-Benz?

Common causes include a faulty crankshaft position sensor, damaged or misaligned timing components, wiring issues, or a failing engine control module (ECM).

Can a dirty or damaged crankshaft position sensor cause code P0372?

Yes, a dirty, damaged, or malfunctioning crankshaft position sensor is one of the most common causes of this code.

How can I diagnose the P0372 code in my Mercedes-Benz?

Start by checking the crankshaft position sensor for damage, inspecting the wiring and connectors for faults, and verifying the timing components for alignment or wear.

Is it safe to drive with a P0372 code on my Mercedes-Benz?

Driving with this code can lead to poor engine performance and potentially cause further damage, so it's best to address the issue promptly.

How do I fix the P0372 code on my Mercedes-Benz?

Repairs may include replacing a faulty crankshaft position sensor, repairing damaged wiring or connectors, or inspecting and adjusting the timing components.

Can a failing ECM trigger the P0372 code?

Yes, although less common, a failing engine control module (ECM) can cause this code if it's unable to process timing signals correctly.

Is special equipment needed to troubleshoot the P0372 code?

A diagnostic scan tool, multimeter, and possibly an oscilloscope may be needed to properly diagnose and test the crankshaft position sensor and related circuits.

How much does it typically cost to repair a P0372 code on a Mercedes-Benz?

Repair costs can vary but may range from $150 to $400, depending on whether youâ€™re replacing the crankshaft position sensor or addressing wiring and timing issues.