DTC P16EA

DTC P16EA:  Electric Engine Coolant Pump Relay Stuck On

General Description 

Courtesy of HONDA, U.S.A., INC.

The electric engine coolant pump varies the pump revolution speed according to the powertrain control module (PCM) outputs signal. The PCM outputs signal (EWP_C(SWP)) to the electric engine coolant pump and feeds back the revolution speed (EWP_REV(NWP)) from the electric engine coolant pump to control the revolution speed. Since the flow rate of the pump is in proportion to the revolution speed, the flow rate increases as the revolution speed is raised. After the vehicle OFF (LOCK) mode, the PCM turns off the electric engine coolant pump relay. The PCM outputs electric engine coolant pump operation command signal when the electric engine coolant pump relay is off to check for electric engine coolant pump relay stuck on. The PCM detects a malfunction and stores a DTC when the revolution speed is equal to or more than the set value continuously for the prescribed time or more to the electric engine coolant pump operation command when the electric engine coolant pump relay is off.

Monitor Execution, Sequence, Duration, DTC Type 

Enable Conditions 

Malfunction Threshold 

When the electric engine coolant pump revolution speed is 600 rpm or more continuously for 5 seconds or more while the engine EWP relay is off.

Possible Cause 

NOTE:  The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

• Electric engine coolant pump relay stuck on
• PCM internal circuit failure

Diagnosis Details 

Conditions for setting the DTC 

When a malfunction is detected, a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory. The MIL does not come on.

Conditions for clearing the DTC 

The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.