Open circuit or poor connection in the stator temperature switch wiring or connector; Faulty stator temperature switch (stuck open or internally open); Corroded or loose terminals at the transmission internal harness or case connector; Short to voltage on the signal wire from damaged or chafed insulation; Transmission fluid overheating, level or condition problem causing the switch to open genuinely; Fault in the transmission control module or its power and ground supplies.

P1874

TCC Stator Temp. Switch Circuit High.

Cadillac
Powertrain
Manufacturer code
Medium severity

How this code is built

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

What it means

P1874 on a Cadillac means the transmission control module has seen a high voltage on the torque converter clutch (TCC) stator temperature switch circuit. The switch is a thermal switch used to monitor converter or fluid temperature, and the module sees a signal level that is out of the expected range for the current conditions. The exact switch location and the way it is used can vary by model and transmission, so check the model-specific wiring information.

Symptoms

Check engine or transmission warning light on
TCC lock-up inhibited or erratic, giving poorer fuel economy
Transmission running hotter than normal or temperature readings looking wrong
Occasional harsh or delayed shifts
Torque converter shudder or flare at cruising speed

Possible causes

Open circuit or poor connection in the stator temperature switch wiring or connectorlikely
Faulty stator temperature switch (stuck open or internally open)likely
Corroded or loose terminals at the transmission internal harness or case connectorpossible
Short to voltage on the signal wire from damaged or chafed insulationpossible
Transmission fluid overheating, level or condition problem causing the switch to open genuinelypossible
Fault in the transmission control module or its power and ground suppliesrare

How to diagnose

Read all stored and pending codes and note the freeze frame data, including transmission temperature, speed and TCC status
Check transmission fluid level and condition, looking for a burnt smell, dark colour or debris
Visually inspect the transmission connector and external harness for damage, corrosion, chafing, fluid ingress and bent or pushed-back pins
Check live data to see whether the switch state changes as the transmission warms up and compare with the expected behaviour for this model
Disconnect the switch and measure its resistance or continuity at different temperatures, following the model-specific specification
Check the signal wire for continuity back to the control module and for a short to voltage or ground
Check the control module power and earth supplies and look for related codes pointing to a shared wiring fault
Confirm whether the transmission is genuinely overheating before condemning the switch

How to fix

Repair or replace damaged wiring and clean or renew corroded terminals and connectors
Replace the stator temperature switch or the internal harness assembly if it tests faulty
Correct the transmission fluid level or change the fluid and filter if it is degraded, and rectify any cause of overheating
Repair any short to voltage on the signal circuit
Replace or repair the transmission control module only after wiring and switch faults are ruled out, and check whether a software update applies to the vehicle

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but TCC operation may be limited and a genuine overheating problem could damage the transmission. Have it checked soon and avoid towing or heavy loads, and stop if the transmission gets hot or shifts badly.

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