AutoCodes – GMC – P1844 GMC

P1844 GMC Code - Transmission Fluid Pressure Sensor/Switch 'A' Circuit Intermittent

Quick Answer

The Torque Converter Clutch (TCC) release switch is part of the automatic Transmission Fluid Pressure (TFP) manual valve position switch. Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Transmission Fluid Pressure Sensor/Switch 'A'. 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: P1844 GMC indicates Transmission Fluid Pressure Sensor/Switch 'A' Circuit Intermittent.
Common causes: Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Transmission Fluid Pressure Sensor/Switch 'A'.
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 1,483

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 Jan 30, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1844 GMC Description

The Torque Converter Clutch (TCC) release switch is part of the automatic Transmission Fluid Pressure (TFP) manual valve position switch. The TFP manual valve position switch is mounted to the transmission valve body. The TCC release switch is a normally-closed switch.
When the TCC is released, TCC release fluid pressure opens the TCC release switch which opens the TCC release pressure circuit. When the voltage on the circuit is high (switch open), the Powertrain Control Module (PCM) recognizes that the TCC is no longer engaged.

OBDII Code P1844 GMC - Transmission Fluid Pressure Sensor/Switch 'A' Circuit Intermittent - AutoCodes.com — P1844 GMC Code - Transmission Fluid Pressure Sensor/Switch 'A' Circuit Intermittent

What does this mean?

What are the Possible Causes of the DTC P1844 GMC?

Low transmission fluid level
Dirty transmission fluid
Faulty Transmission Fluid Pressure Sensor/Switch 'A'
Transmission Fluid Pressure Sensor/Switch 'A' harness or connectors
Transmission Fluid Pressure Sensor/Switch 'A' circuit is open or shorted
Transmission internal mechanical problem

How to Fix the DTC P1844 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 P1844 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.