What Does P273B Mean?
The TCM is receiving a signal from Transmission Fluid Temperature Sensor B that is implausible compared to sensor A or engine coolant temperature. This indicates sensor drift, calibration issues, or sensor location exposure problems.
Common Causes
35%
Temperature sensor B reading out of range due to internal degradation or contamination
20%
Sensor B located in area with abnormal fluid temperature causing legitimate but unexpected readings
20%
Intermittent wiring connection causing erratic sensor signal to TCM
15%
Failed primary temperature sensor A causing TCM to misinterpret sensor B as faulty
10%
High resistance in sensor ground circuit affecting signal accuracy
Diagnostic Steps
1
Step 1: Using scan tool, compare live data from temperature sensor A and B readings to each other and to engine coolant temperature
2
Step 2: Allow vehicle to reach full operating temperature and verify both sensors track together appropriately
3
Step 3: Measure sensor B resistance at known fluid temperature and compare to manufacturer specifications
4
Step 4: Check sensor signal wire for high resistance or poor ground connections affecting voltage signal
5
Step 5: Swap sensors A and B if possible to determine if fault follows sensor or remains with circuit
Estimated Repair Cost
$100 - $400
Parts + labor, varies by vehicle and location
The TCM is receiving a signal from Transmission Fluid Temperature Sensor B that is implausible compared to sensor A or engine coolant temperature. This indicates sensor drift, calibration issues, or sensor location exposure problems.
The most common cause of P273B (Transmission Friction Element "H" Apply Time Range/Performance) is: Temperature sensor B reading out of range due to internal degradation or contamination
Typical repair costs for P273B range from $100 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
May prevent TCM from accurately monitoring transmission temperature, potentially allowing overheating conditions. This could lead to transmission damage but typically triggers limp mode before critical failure occurs.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P273B to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Automatic Transmission Monitoring System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
