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P1812

Transmission Over Temperature Condition

2004-2007 Buick Rainier 4.2L I6

Critical SeverityPowertrain

Description

The TCM detected that the transmission fluid temperature has exceeded the maximum safe operating temperature. Excessive heat is the primary killer of automatic transmissions.

Symptoms

  • Check Engine Light
  • Transmission may enter limp mode
  • Harsh or delayed shifts
  • Hot transmission fluid smell
  • Possible loss of forward gears

Common Causes

  • Low transmission fluid level
  • Clogged transmission cooler
  • Failed transmission cooler lines
  • Towing beyond capacity
  • Worn torque converter clutch causing excess heat
  • Transmission slipping internally

Diagnostic Steps

  1. Check transmission fluid level and color
  2. Inspect transmission cooler and lines for restriction
  3. Test transmission temperature with scan tool
  4. Check for transmission slipping
  5. Inspect torque converter clutch operation

Repair Notes

Check fluid level immediately. Inspect cooler and lines. Do not drive with overheated transmission. If fluid is burnt (dark brown/black with burnt smell), internal damage likely.

Related Codes

P0218Transmission Over Temperature ConditionP0710Transmission Fluid Temperature Sensor CircuitP0711Transmission Fluid Temperature Sensor Range/PerformanceP1811Maximum Adapt and Long ShiftP1811Maximum Adapt and Long ShiftP1811Maximum Adapt and Long ShiftP1811Maximum Adapt and Long ShiftP1811Maximum Adapt and Long ShiftP1811Maximum Adapt and Long ShiftP1811Maximum Adapt and Long ShiftP1811Maximum Adapt and Long Shift

Other Powertrain Codes

P1812 on Other Vehicles

Common Questions

What does code P1812 mean on a 2004-2007 Buick Rainier?

P1812 stands for "Transmission Over Temperature Condition". The TCM detected that the transmission fluid temperature has exceeded the maximum safe operating temperature. Excessive heat is the primary killer of automatic transmissions.

What are the symptoms of P1812 on a Buick Rainier?

Common symptoms of P1812 include: Check Engine Light, Transmission may enter limp mode, Harsh or delayed shifts, Hot transmission fluid smell, Possible loss of forward gears.

What causes P1812 on a 2004-2007 Buick Rainier?

Common causes of P1812 include: Low transmission fluid level, Clogged transmission cooler, Failed transmission cooler lines, Towing beyond capacity, Worn torque converter clutch causing excess heat, Transmission slipping internally.

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