What does P1843 mean on a Chevy?

P1843. 1-2 Shift Solenoid Circuit High Voltage. Applies to Impala, Malibu, Monte Carlo, Lumina, Venture.

What causes P1843 on a Chevy?

Faulty 1-2 shift solenoid valve Open in the 1-2 shift solenoid control or ignition feed circuit Corroded AT inline 20-way connector Internal transmission harness open or shorted to voltage Faulty powertrain control module driver

How do I fix P1843 on a Chevy?

Command the 1-2 shift solenoid on and off with a Tech2 scan tool Measure solenoid resistance and compare to GM specification Test the control and feed circuits for opens and shorts to voltage Inspect the internal harness and AT inline connector Replace the shift solenoid if circuits test normal, then clear and road test

Code

P1843

1-2 Shift Solenoid Circuit High Voltage

Category: Powertrain - Transmission
Severity: Check Engine Light
Applies to: Impala, Malibu, Monte Carlo, Lumina, Venture
Related: No single generic twin. See OBD Codes List

What it means

P1843. 1-2 Shift Solenoid Circuit High Voltage. This Chevy-enhanced code applies to Impala, Malibu, Monte Carlo, Lumina, Venture.

Findings, check these first

Faulty 1-2 shift solenoid valve
Open in the 1-2 shift solenoid control or ignition feed circuit
Corroded AT inline 20-way connector
Internal transmission harness open or shorted to voltage
Faulty powertrain control module driver

Standard procedure

Command the 1-2 shift solenoid on and off with a Tech2 scan tool
Measure solenoid resistance and compare to GM specification
Test the control and feed circuits for opens and shorts to voltage
Inspect the internal harness and AT inline connector
Replace the shift solenoid if circuits test normal, then clear and road test

Look up another code

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Sources and review

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Last updated 2026-09-13.

Report a correction for P1843. Include your vehicle, the issue and a source if you have one.