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P1847

2-3 Shift Solenoid Circuit High Voltage.

  • Buick
  • Powertrain
  • Manufacturer code
  • Medium severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
8
AreaTransmission
47
FaultThe specific fault in that area

What it means

P1847 on a Buick means the transmission control module has detected a high voltage condition in the 2-3 shift solenoid circuit. The module sees a voltage higher than it expects when it commands the solenoid, which usually points to an open circuit, a short to voltage or a failed solenoid. The fault can stop the 2-3 shift working correctly, so the gearbox may default to a fixed gear or limp mode.

Symptoms

  • Gearbox warning or check engine light on
  • Harsh, delayed or missed 2-3 upshift
  • Gearbox stuck in one gear or in limp mode
  • Flare or slip between second and third gear
  • Poor fuel economy because the car cannot reach the higher gears
  • Torque converter clutch not engaging in some cases

Possible causes

  • Faulty 2-3 shift solenoid with an open internal windinglikely
  • Damaged, chafed or open-circuit wiring between the solenoid and the control modulelikely
  • Corroded, loose or contaminated connector at the transmission internal harness or the modulelikely
  • Wiring shorted to a voltage supplypossible
  • Transmission fluid contamination or debris damaging the solenoid or the internal harnesspossible
  • Faulty transmission control module driver circuitrare
  • Low or incorrect system voltage affecting the module's readingsrare

How to diagnose

  1. Read all stored and pending codes and note the freeze frame data, including any other solenoid or electrical codes
  2. Check battery condition and charging voltage, as low or erratic voltage can upset module readings
  3. Check the transmission fluid level and condition, looking for burnt smell, metal debris or dark contaminated fluid
  4. Visually inspect the external transmission harness and connectors for chafing, heat damage, corrosion or bent pins
  5. Check the solenoid circuit for supply voltage, continuity and any short to voltage with the connector unplugged, following the wiring diagram for the specific model and transmission
  6. Measure the solenoid resistance at the transmission connector and compare it with the manufacturer's specification for that transmission
  7. Use a scan tool that supports bi-directional control to command the solenoid and watch the circuit response
  8. Only after wiring and solenoid are proven good, check the control module power, ground and driver output

How to fix

  • Replace the 2-3 shift solenoid if its resistance is out of specification or it is open circuit
  • Repair or replace damaged wiring, and clean or replace corroded or damaged connectors and terminals
  • Repair any short to voltage found in the harness
  • Replace the internal wiring harness or pass-through connector if it is faulty (procedure varies by transmission)
  • Change the fluid and filter and repair any cause of contamination if debris is found
  • Replace or reprogram the transmission control module only if it is confirmed faulty

Can I keep driving?

Medium severity

The car can usually be driven short distances, but the gearbox may be in limp mode with reduced performance, so avoid heavy loads and long journeys. Book it in soon, as continued driving with a slipping or stuck gear 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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