ECT Sensor Below Thermostat Regulating Temperature
Possible Causes:
Check the operation of the thermostat (it may be stuck open).Coolant level is too low, or the coolant mixture is incorrect.ECT sensor signal circuit has a high resistance condition.ECT sensor is damaged or it has failed.Trouble Code: P0401
Insufficient EGR Flow Detected
Possible Causes:
Base engine problem (e.g., a severely restricted exhaust).EGR vacuum hoses damaged, loose or routed incorrectly.EGR passages or intake passages clogged or restricted.EGR solenoid valve is clogged (carbon), damaged or has failed.TSB 87-65-22 contains a repair procedure for this code.
Answers & Comments
Trouble Code: P0128
ECT Sensor Below Thermostat Regulating Temperature
Possible Causes:
Check the operation of the thermostat (it may be stuck open).Coolant level is too low, or the coolant mixture is incorrect.ECT sensor signal circuit has a high resistance condition.ECT sensor is damaged or it has failed.Trouble Code: P0401
Insufficient EGR Flow Detected
Possible Causes:
Base engine problem (e.g., a severely restricted exhaust).EGR vacuum hoses damaged, loose or routed incorrectly.EGR passages or intake passages clogged or restricted.EGR solenoid valve is clogged (carbon), damaged or has failed.TSB 87-65-22 contains a repair procedure for this code.