PACCAR DAF P00B7 Fault Code – Coolant Pump Speed Too Low | MX-13 troubleshooting Information

PACCAR / DAF P00B7 Fault Code Technical Information

This technical document provides diagnostic and troubleshooting information for DTC P00B7 used on applicable PACCAR/DAF engine configurations, including MX-13 applications.

The P00B7 fault is detected by the PCI ECU (D420) when the average coolant pump speed is approximately 400 rpm lower than expected.

⚙️ Diagnostic Condition

The diagnostic runs continuously while the engine is running and the coolant pump has been commanded to operate at high speed.

🔍 Possible Causes of P00B7

• Prolonged engine starting of more than approximately 12 seconds
• Malfunctioning coolant pump speed sensor
• Coolant pump speed sensor wiring problem
• Malfunctioning two-stage coolant pump
• Coolant pump wiring or control problem

🔧 Coolant Pump Speed Sensor Information

The coolant pump speed is measured by the coolant pump speed sensor F805.

The PCI ECU cannot directly detect an open circuit or short circuit in the coolant pump speed sensor or its wiring. Instead, the ECU determines whether the expected coolant pump speed has been reached.

If the PCI ECU receives no usable signal from the coolant pump speed sensor while the engine is running, DAVIE may display an actual coolant pump speed of 333 rpm. The document identifies 333 rpm as the default/minimum displayed value under these conditions.

⚙️ Two-Stage Coolant Pump Operation

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

• Solenoid activated: Coolant pump operates at high speed.
• Solenoid not activated: Coolant pump operates at low speed.

The PCI ECU changes coolant pump operation depending on the cooling demand from the engine or vehicle systems.

🛠️ Repair Verification

1. Clear all diagnostic trouble codes (DTCs).
2. Test drive or operate the vehicle until the required diagnostic and set conditions are met.
3. Check whether DTC P00B7 returns.

If the DTC does not return: the repair is considered successful.

If the DTC returns: additional diagnosis is required.