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Home >> Chrysler >> 2011 >> 300 C, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 82 (5.7L - DTCS P000B To P0159 - NGC - 3500 Cab & Chassis) >> Diagnosis and Testing >> P0128-Thermostat Rationality >> Possible Causes

Possible Causes

WARNING: This page is about a different car, the 2011 RAM Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
Possible Causes 
LOW COOLANT LEVEL
THERMOSTAT
SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
TEMPERATURE SENSOR
SIGNAL CIRCUIT OPEN
(K900) SENSOR GROUND CIRCUIT OPEN
(G931) SENSOR GROUND CIRCUIT OPEN
SIGNAL CIRCUIT SHORTED TO GROUND
(K2) ECT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
(G31) AAT SIGNAL CIRCUIT SHORTED TO THE (G931) SENSOR GROUND CIRCUIT OPEN
OTHER POSSIBLE CAUSES
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Refer to  PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE  .