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P1852

Brake Band Apply Solenoid Low Voltage.

  • GM
  • Powertrain
  • Manufacturer code
  • Medium severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
8
AreaTransmission
52
FaultThe specific fault in that area

What it means

P1852 on GM vehicles means the transmission control module has detected a low voltage condition in the brake band apply solenoid circuit. The control unit monitors the circuit when it commands the solenoid, and it sets the code when the voltage is lower than expected. It is a circuit fault, so the cause is usually electrical, though it can be internal to the solenoid or the control unit. Which transmissions use this solenoid depends on the model and year.

Symptoms

  • Transmission warning light or check engine light on
  • Harsh, delayed or missing shifts
  • Transmission stuck in one gear (limp mode)
  • Slipping or flaring between gear changes
  • Reduced performance or poor fuel economy
  • Gear selection that feels inconsistent when cold or hot

Possible causes

  • Damaged, chafed or shorted wiring between the transmission control module and the brake band apply solenoidlikely
  • Corroded, loose or contaminated connector at the transmission or control modulelikely
  • Faulty brake band apply solenoid with low or shorted internal resistancepossible
  • Low or unstable system voltage from a weak battery, poor earth or charging faultpossible
  • Transmission fluid leaking along the wiring harness into the connector, causing a poor connectionpossible
  • Internal fault in the transmission control module driver circuitrare

How to diagnose

  1. Read all stored codes and freeze frame data, and note whether other transmission or voltage-related codes are present.
  2. Check battery condition and charging voltage, and inspect the main earths, as low system voltage can set circuit faults.
  3. Visually inspect the transmission wiring harness and connector for chafing, heat damage, fluid contamination and corrosion.
  4. Check the transmission fluid level and condition, following the manufacturer's procedure for your model.
  5. Disconnect the connector and check the solenoid resistance against the specification for your transmission.
  6. Test the wiring between the solenoid and control module for continuity, short to earth and short to supply.
  7. With a suitable scan tool, command the solenoid and check the supply and control signals at the connector.
  8. Only after wiring and solenoid are proven good, consider testing or replacing the control module, following the manufacturer's procedure.

How to fix

  • Repair or replace damaged wiring and secure the harness away from heat and sharp edges.
  • Clean or replace corroded or contaminated connectors and terminals.
  • Replace the brake band apply solenoid if its resistance or operation is out of specification.
  • Repair the battery, charging system or earth connections if voltage is low or unstable.
  • Cure any fluid leak that is wicking into the connector, and correct the fluid level.
  • Replace or repair the transmission control module only if it is confirmed faulty, and then program it as required.

Can I keep driving?

Medium severity

The car can usually be driven a short distance, but the transmission may be in limp mode with harsh or missing shifts. Get it checked soon, as continued driving with slipping or wrong gear application can cause further transmission damage.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

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