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Home >> Ford >> 2009 >> Flex Limited, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1139 (Engine Controls - Powertrain DTC Charts And Descriptions (Except Diesel & Hybrid)) >> DTC Diagnosis >> P128A - Cylinder Head Temperature (CHT) Sensor Circuit Intermittent/Erratic

P128A - Cylinder Head Temperature (CHT) Sensor Circuit Intermittent/Erratic

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2008 Mercury Sable, 2008 Mercury Mountaineer, 2008 Mercury Milan, 2008 Mercury Mariner, and 2008 Mercury Grand Marquis. However, it is still accessible from the selected car via links, so may be relevant.
P128A - CYLINDER HEAD TEMPERATURE (CHT) SENSOR CIRCUIT INTERMITTENT/ERRATIC

Description:  Indicates the CHT circuit became intermittently open or shorted while the engine was running.
Possible Causes: 
  • Damaged harness or connector
  • Damaged sensor
Diagnostic Aids:  Monitor the CHT on a scan tool. Look for sudden changes in the reading when the harness is wiggled or the sensor is tapped.
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
All   - - refer to PINPOINT TEST DL .