2B59

2B59 - P0128

Information saved in
DME

Fault code
2B59 - P0128

Fault text
Coolant thermostat monitoring

Fault description
Coolant Thermostat (Coolant Temperature Below
Thermostat Regulating Temperature)

Condition for fault identification
Test condition:
For the period K_TMOT_OBD_DIFF_T_DELTA the
sensor deviates from the model by more than -25� Kelvin
(K_TMOT_OBD_DIFF_HIGH)...
Terminal condition: Engine running
Voltage condition:
none

Condition for fault memory entry
Once during warm-up phase

Action in service
1. Replace thermostat
2. Perform electrical check on coolant sensor and replace as
indicated

Fault effect and breakdown warning
Engine warms to normal operating temperature very slowly /
ineffective interior heating / MIL on after engine runs 2x

Driver information
Warning light:
MIL

Service instruction
none