P0738
System
Powertrain (Transmission)
Scanner som krävs
Full-system scanner (engine, ABS, SRS, transmission, service resets)

Gear 8 Incorrect Ratio

Understand P0738, common causes, and the right FOXWELL scanner to diagnose it.

Eighth gear ratio incorrect on 8–10 speed automatics.

Vanliga symptom

  • Missing top gear
  • Reduced fuel economy

Typiska orsaker

  • Failed 8th gear clutch
  • TCM calibration issue
  • Low fluid
  • Solenoid sticking

Vilken scanner behöver du?

Full-system scanner (engine, ABS, SRS, transmission, service resets)

Använd live-data och freeze frame innan du byter delar. ABS-, SRS- och U-koder kräver oftast en fullsystems-scanner.

Diagnostiktips

  • Spara freeze frame när koden först sätts
  • Rensa koden först efter att orsaken är åtgärdad
  • Kontrollera relaterade väntande koder
  • Verifiera batterispänning över 12,4 V innan du misstänker sensorer

Rekommenderade FOXWELL-scannrar

Vanliga frågor

Can I diagnose P0738 with a basic code reader?
P0738 may set in the engine module, but related diagnostics often benefit from an enhanced or full-system scanner with live data and freeze frame.
Is it safe to drive with P0738?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.