Volvo Engine D11L (Tier 4) Fault Code: P012800 PID: PSID 109 FMI: 12 Coolant Thermostat (Coolant Temp Below Thermostat Regulating Temperature) – No Sub Type Information

CONTROL UNIT:
Engine ECU

FAILURE EVENT:
Engine coolant temperature lower than calculated (thermostat remains open). Below 65?C (149?F).

SYMPTOM:
Low engine temperature.

CONDITIONS:
1. Engine running.
2. Ambient air temperature between -40?C (-40?F) and 50?C (122?F).
3. Ambient air pressure between 75 kPa (10.9 psi) and 105 kPa (15.2 psi).
4. Engine speed below 1800 rpm.
5. Engine torque between 400 Nm and 2000 Nm.
6. Engine coolant temperature below 53?C (127?F) at start of engine.
7. Engine coolant temperature below 65?C (149 ?F).
8. Vehicle speed above 1 km/h (0.6 mph).

INHIBITING THE DTC:
1. P009501 / MID128 PID105 FMI12 / SE2507-12
2. P009511 / MID128 PID105 FMI4 / SE2507-4
3. P009513 / MID128 PID105 FMI5 / SE2507-5
4. P011501 / MID128 PID110 FMI12 / SE2606-12
5. P011511 / MID128 PID110 FMI4 / SE2606-4
6. P011513 / MID128 PID110 FMI5 / SE2606-5
7. P01152A / MID128 PID110 FMI10 / SE2606-10
8. P033531 / MID128 SID22 FMI9 / SE2701-9
9. P033538 / MID128 SID22 FMI8 / SE2701-8
10. P222601 / MID128 PID108 FMI12 / EF2138-12
11. P222612 / MID128 PID108 FMI3 / EF2138-3
12. P222613 / MID128 PID108 FMI5 / EF2138-5
13. U300001 / MID128 PID158 FMI5 / EF2104-5

POSSIBLE CAUSES:
1. Defective (held open) thermostat.
2. Damaged wire harness or connector.
3. Defective coolant temperature sensor.
4. Cooling fan running at high speed.