AutoCodes – GMC – P1842 GMC

P1842 GMC Code - 1-2 Shift Solenoid Circuit Low Input Voltage

Quick Answer

With the engine runtime over 5 seconds, system voltage from 8-18v, Fuel Cutoff inactive, the Powertrain Control Module (PCM) detects an open circuit or a short to ground on the 1-2 Shift Solenoid feedback circuit for 4.3 seconds. Common causes include Faulty 1-2 Shift Solenoid, 1-2 Shift Solenoid harness is open or shorted, 1-2 Shift Solenoid 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: P1842 GMC indicates 1-2 Shift Solenoid Circuit Low Input Voltage.
Common causes: Common causes include Faulty 1-2 Shift Solenoid, 1-2 Shift Solenoid harness is open or shorted, 1-2 Shift Solenoid 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 1,745

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Sep 22, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
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Code P1842 GMC Description

OBDII Code P1842 GMC - 1-2 Shift Solenoid Circuit Low Input Voltage - AutoCodes.com — P1842 GMC Code - 1-2 Shift Solenoid Circuit Low Input Voltage

What does this mean?

What are the Possible Causes of the DTC P1842 GMC?

Faulty 1-2 Shift Solenoid
1-2 Shift Solenoid harness is open or shorted
1-2 Shift Solenoid circuit poor electrical connection

How to Fix the DTC P1842 GMC?

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 P1842 GMC 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.