Skip to content
GTECH Calibration
Portal

P1873

TCC Stator Temp Switch Circuit Low.

  • GM
  • Powertrain
  • Manufacturer code
  • Medium severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
8
AreaTransmission
73
FaultThe specific fault in that area

What it means

On GM vehicles P1873 means the transmission control module has seen a low voltage in the torque converter clutch (TCC) stator temperature switch circuit. The switch tells the control module when the converter or fluid is running hot, so it can adjust or limit TCC apply. The module sets the code when the signal sits low (shorted to ground or the switch stuck closed) when it should not.

Symptoms

  • Check engine or service transmission warning light on
  • Torque converter clutch not applying, or applying erratically
  • Slightly worse fuel economy on motorway cruising
  • Transmission running hot or overheating warning on some models
  • Shuddering or flaring around converter lock-up speeds
  • Transmission held in a default strategy with firmer or delayed shifts

Possible causes

  • Wiring in the stator temperature switch circuit chafed or shorted to groundlikely
  • Faulty stator temperature switch, or one stuck closedlikely
  • Damaged or contaminated connector at the transmission or control module, including fluid ingresspossible
  • Genuinely overheated transmission fluid from towing, low fluid level or a restricted coolerpossible
  • Faulty transmission control modulerare
  • Internal harness fault inside the transmissionrare

How to diagnose

  1. Read all stored and pending codes and note the freeze frame data, including transmission fluid temperature and vehicle speed at the time it set
  2. Check the transmission fluid level and condition, looking for a burnt smell or debris that suggests overheating
  3. Inspect the wiring and connectors from the transmission to the control module for chafing, corrosion, fluid contamination or pinned wires
  4. Using live data, see whether the switch state and fluid temperature readings make sense when the transmission is cold and then warm
  5. Check the switch circuit for a short to ground with the connector unplugged, using the wiring diagram for the exact model
  6. Test the switch itself against the manufacturer's resistance or continuity specification, as the procedure varies by transmission
  7. Check the cooler lines and cooler flow if the fluid appears to have run hot
  8. Clear the code and road test to confirm whether it returns

How to fix

  • Repair or replace the damaged wiring and clean or renew the faulty connector terminals
  • Replace the stator temperature switch or internal harness section if it fails testing
  • Correct the fluid level and renew the fluid if it is burnt or contaminated
  • Clear any restriction in the transmission cooler or lines to restore proper cooling
  • Replace or reprogram the transmission control module only after wiring and switch have been proven good and a fault is confirmed

Can I keep driving?

Medium severity

The car can usually be driven short-term, but the converter clutch may not work properly and any real overheating could damage the transmission. Book it in soon, and avoid towing or heavy loads until it is checked.

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

This code for other makes

Nearby codes