Cooling System - SES Lamp ON/DTC P0128 Set
Service Measure
Engine Electrical
M12 201 05
03/25/2005
Subject
DME (EMS2000 or MS5150) Fault Code P0128 - Coolant Thermostat
Model
R50 (Cooper) R52 (Cooper and Cooper S) and R53 (Cooper S) equipped with W10 and W11 engines.
Complaint
2002-2006 Mini Cooper (R50) L4-1.6L (W10) Page 94
The customer complains the Service Engine Soon Lamp is illuminated. When diagnosed the following fault is found in the DME (EMS2000 or
M55150) memory.
Fault Code P0128 - Coolant thermostat coolant temp below thermostat control temp
Cause
An air pocket in the cooling system can cause operational errors of the cooling system causing faults to store in memory. One of the following areas
can be the cause.
1. Air pockets near the engine thermostat can cause the thermostat to have a delayed opening. This will cause a slight over temperature in the
engine cooling system for short period of time signaling the DME with incorrect data via the coolant temperature sensor.
2. Air pockets near the engine coolant temperature sensor can incorrectly inform the DME of proper engine temperature during the warm up
phase.
If the DME is supplied with incorrect cooling data during the warm up phase then the calculation for the virtual radiator outlet temperature can also
be inaccurate causing the above fault to store in memory.
Measure
1. Bleed cooling system.
2. Do not replace any parts.
3. Connect vehicle to a FASTA transmitting diagnostic device and perform short test. Once the short test has concluded verify the vehicle has
been identified properly.
4. If a resolution cannot be found through bleeding of the cooling system then please submit a PuMA Case to the Drivetrain Technical Hotline
