Coolant level sensor low water level, circuit 1 (depending on installation often colt circuit, battery)
• Check that the coolant level is within an acceptable range in the expansion tank for the hybrid battery cooling system. If the level is too low check for leakages. If glycol or traces of glycol is found in the HRU the leakage has to be located and repaired. • Run “deaeration mode” for the battery cooling pump. Refill coolant if necessary. • Check that T181 is connected. • Check that E81-B is connected. • Check that the cable harness by measuring that E81-B7 is connected to T181-B, E81-B4 is connected to T181-A and E81-B2 is connected to T181-C. If there is no connection, change the cable. • Apply 24V on the component with + on T181-B and – on T181-A and measure the outgoing voltage between T181-A and T181-C. If the voltage is >2V, change the sensor. • Change the BMU(E81)
What you'll see
No driver-visible symptom recorded.
System reaction
• Coolant pump RES stops, the hybrid power is reduced to prevent over temperature in the battery pack. • Amber warning lamp "Hybrid System Fault" is shown in ICL
Diagnostic depth
Coolant level sensor signal
•Leakage. •Temperature change. •Previous air pockets collapsed. •Sensor not connected •Sensor malfunction.