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DTC codes / GM codes / P1833

P1833 · GMA/T Solenoids Power Circuit Low Voltage

P1833 on a GM vehicle means the transmission control module (TCM) has detected low voltage on the power feed circuit that supplies the automatic transmission solenoids. The TCM monitors the solenoid power circuit and sets this code when the voltage drops below the expected threshold, indicating a short to ground, high resistance, or a failing power source.

SystemPowertrain
Code typeGM specific
SeverityMedium
Fix difficultyProfessional
AreaTransmission

Symptoms you may notice

  • Illuminated check engine light or transmission warning light
  • Harsh or delayed shifting, or the transmission stuck in a single gear (limp mode)
  • Slipping or flaring during gear changes
  • No symptoms besides the warning light in some cases
  • Transmission may not engage drive or reverse when cold
  • Reduced fuel economy due to improper shift scheduling

Common causes, most likely first

  1. Chafed or shorted wiring harness between the TCM and transmission solenoids, often near hot or moving components
  2. Corroded or loose electrical connector at the transmission solenoid pack or TCM
  3. Failing transmission solenoid pack drawing excessive current or shorting internally
  4. Blown fuse or faulty relay in the solenoid power circuit
  5. High resistance in the power feed wire due to internal corrosion
  6. Defective TCM not supplying proper voltage to the solenoids

How to diagnose and fix it

  1. Inspect the solenoid power circuit fuse and relay; replace if blown or faulty
  2. Disconnect the battery and check the wiring harness from the TCM to the transmission for chafing, corrosion, or loose pins
  3. Measure resistance of the solenoid pack at the connector and compare to GM specifications
  4. Perform a voltage drop test on the power feed wire while the circuit is loaded
  5. Check for continuity to ground on the power circuit to rule out a short
  6. If wiring and connectors are good, test the TCM output signal with a scan tool or oscilloscope
  7. Replace the faulty solenoid pack or TCM only after confirming the circuit integrity

Don't overlook the solenoid power feed

  • A common misdiagnosis is replacing the transmission solenoid pack when the real problem is a chafed power wire near the exhaust manifold or battery tray.
  • This code can be set by a weak battery or charging system issue that causes low voltage during cranking, so always check battery health first.
  • Some GM models use a shared power circuit for multiple solenoids, so a single shorted solenoid can pull down voltage for the entire circuit and set P1833.
  • The TCM may set P1833 intermittently if the wiring harness rubs only during certain engine movements, so wiggle-test the harness while monitoring live data.
  • After repairs, the TCM may need a relearn procedure or clear adaptation to restore normal shift feel, even after the code is cleared.

Can I keep driving with P1833?

Driving with P1833 is not recommended because the transmission may enter limp mode or shift erratically, which can be unsafe in traffic. If you must drive, avoid heavy acceleration and have the vehicle inspected as soon as possible.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for GM vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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