PACCAR MX (2004 Emissions) Fault Code: P011A Coolant Pump Speed – Stalled Pump Detected

PACCAR MX (2004 Emissions) Fault Code: P011A Coolant Pump Speed – Stalled Pump Detected

SET CONDITIONS:
The PCI ECU (D420) detects that the coolant pump speed is below 340 rpm for more than 0.5 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the engine is running.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to inactive when the fault is no longer detected.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. Broken or missing poly-V belt
2. Slipping poly-V-belt Check poly-V-belt tensioner and idlers
3. Malfunctioning coolant pump speed sensor or wiring
4. Malfunctioning two-stage coolant pump
5. Malfunctioning two-stage coolant pump

ADDITIONAL INFORMATION:
1. The coolant pump speed is measured by the coolant pump speed sensor (F805).

IMPORTANT: The PCI ECU is not able to detect a short circuit or an open circuit of the coolant pump speed sensor or its wiring. It can only detect if the expected coolant pump speed is reached.

If no signal is received from the coolant pump speed sensor, the coolant pump speed (actual) in the diagnostic service tool displays 333 rpm when the engine is running.

2. When the engine is running, the minimum coolant pump speed (actual) which can be displayed in the diagnostic service tool is 333 rpm.

3. For this diagnostic the coolant speed is monitored for detection of a stalled coolant pump by monitoring the poly-V belt presence or slip.

4. In case of a malfunction on the coolant pump speed sensor or wiring, this DTC also becomes active.

5. The two-stage coolant pump (L142) is controlled by the PCI ECU (D420).

IMPORTANT: The PCI ECU is not able to detect a short circuit or an open circuit of the coolant pump solenoid or its wiring. It can only detect if the expected coolant pump speed is reached.

6. The two-stage coolant pump (L142) is controlled by the PCI ECU (D420).

IMPORTANT: The PCI ECU is not able to detect a short circuit or an open circuit of the coolant pump solenoid or its wiring. It can only detect if the expected coolant pump speed is reached.

7. When this DTC is active:
– The engine torque is reduced.
– The engine runs in protection mode.