AutoCodes – Mercury – P1900 Mercury

P1900 Mercury Code - Output Shaft Speed Circuit Intermittent Malfunction

Quick Answer

The Output Shaft Speed (OSS) sensor provides the Powertrain Control Module (PCM) with information about the rotational speed of an output shaft. Common causes include Output Shaft Speed (OSS) not installed properly, Faulty Output Shaft Speed sensor, Output Shaft Speed sensor harness is open or shorted. 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: P1900 Mercury indicates Output Shaft Speed Circuit Intermittent Malfunction.
Common causes: Common causes include Output Shaft Speed (OSS) not installed properly, Faulty Output Shaft Speed sensor, Output Shaft Speed sensor harness is open or shorted.
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 1,683

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 13, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1900 Mercury Description

The Output Shaft Speed (OSS) sensor provides the Powertrain Control Module (PCM) with information about the rotational speed of an output shaft. The PCM uses the information to control and diagnose powertrain behavior. In some applications, the sensor is also used as the source of vehicle speed. The sensor may be physically located in different places on the vehicle, depending upon the specific application. The design of each speed sensor is unique and depends on which powertrain control feature uses the information that is generated. The Diagnostic Trouble Code (DTC) will set when the OSS sensor signal to the PCM is irregular or interrupted.

OBDII Code P1900 Mercury - Output Shaft Speed Circuit Intermittent Malfunction - AutoCodes.com — P1900 Mercury Code - Output Shaft Speed Circuit Intermittent Malfunction

What does this mean?

What are the Possible Causes of the DTC P1900 Mercury?

Output Shaft Speed (OSS) not installed properly
Faulty Output Shaft Speed sensor
Output Shaft Speed sensor harness is open or shorted
Output Shaft Speed sensor circuit poor electrical connection

How to Fix the DTC P1900 Mercury?

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 P1900 Mercury 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.

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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.