AutoCodes – Toyota – P1556 Toyota

P1556 Toyota Code - Reactor Temperature Sensor Circuit High

Quick Answer

P1556 Toyota indicates Reactor Temperature Sensor Circuit High. Common causes include Faulty Reactor Temperature Sensor, Reactor Temperature Sensor harness is open or shorted, Reactor Temperature Sensor circuit poor electrical connection. 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: P1556 Toyota indicates Reactor Temperature Sensor Circuit High.
Common causes: Common causes include Faulty Reactor Temperature Sensor, Reactor Temperature Sensor harness is open or shorted, Reactor Temperature Sensor circuit poor electrical connection.
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 7,023

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 Aug 30, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1556 Toyota Description

OBDII Code P1556 Toyota - Reactor Temperature Sensor Circuit High - AutoCodes.com — P1556 Toyota Code - Reactor Temperature Sensor Circuit High

What does this mean?

What are the Possible Causes of the DTC P1556 Toyota?

Faulty Reactor Temperature Sensor
Reactor Temperature Sensor harness is open or shorted
Reactor Temperature Sensor circuit poor electrical connection

How to Fix the DTC P1556 Toyota?

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 P1556 Toyota 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.