Need help with Custom PIDs for Gen 3 Electric Water Pump (21D7) in Torque Pro

Hi everyone,

I’m currently troubleshooting a potential overheating issue on my 2010 Prius (Gen 3) and I need some help verifying the custom PID settings for the Engine Electric Water Pump.

I’ve been using Torque Pro with the standard Prius PID lists, but the Electric Water Pump (Actual vs. Target RPM) isn't showing up correctly. I’m specifically trying to monitor PID 21D7 on Header 7E0.

What I’ve tried so far:

Header: 7E0

Command: 21D7

Current Equation: (D*256)+E

The Result: I’m getting very high raw values like 18176 (Actual) and 8449 (Target) during normal driving.

I suspect I have the wrong multiplier or byte offset for the Gen 3. Does anyone have the verified Equation to convert these raw values into actual RPM?

Also, if anyone has the verified PIDs for the Water Pump Amperage or Duty Cycle to help me see if the pump is cavitating or hitting a blockage, that would be greatly appreciated.

Thanks in advance for the help!

 

Hello there, thank you for the reply.

Appreciate the advice and the corrected equation! I'll update my Torque Pro settings to /4 and see how the numbers look.

I’m struggling with a persistent overheat on my 2010 Prius and need some advice.

What’s been done:

1. Cleaned radiator, thermal valve, and all coolant pipes.
   
   
2. Found a faulty pump rotor; replaced it with a known good one.
   
   
3. Car still overheats on long trips in high heat.
   

Since the lines are clean and the rotor is new, could the pump's internal electronics be failing only when heat-soaked?

Moreover, I tried with car scanner app also, but the water pump parameters it doesn't respond to them. Rest of the parameters the app responds. even that i created custom PID for the water pump parameters but the app (scanner pro) doesn't read at all. see snapshot please.

 

Hi there,
Thank you for your reply too. In fact, i tried with the car scanner app at first place but it doesn't communicate or read Water Pump related values at all and interestingly other values of the engine it reads and variate just fine. see snapshot please.

 

Hi everyone,

I wanted to share my troubleshooting journey regarding a persistent heating issue on my 2010 Prius Gen 3. After a long process of data logging and deep cleaning, I finally identified the culprits. This case study might be helpful for those who have replaced the water pump but are still seeing "heat signs" on the odometer.

Problem:
- Occasional "Heat" warning sign appearing on the dashboard.
- Warning appearing even when OBD2 sensors showed relatively normal temperatures.
- Localized overheating during long trips (200km+).
- High engine load and poor thermal recovery.

Initially, I suspected the electric water pump. Upon inspection, I found the impeller in terrible condition i.e. swollen, damaged, and clearly failing. However, even after replacing it with a known good impeller, the overheating issues persisted. To get to the bottom of it, I used Torque Pro and an OBD2 scanner to monitor the car during a 200km trip. Despite inconsistent pump data, the steady, unrelenting rise in coolant temperatures confirmed that I wasn't dealing with a software glitch, but a system-wide circulation and heat-exchange failure that went far deeper than just the pump motor itself.

Comprehensive Cooling & Exhaust Service:
To solve this, I performed a "Deep Detox" of the cooling and exhaust systems:

1)Professional Radiator Cleaning: Disassembled the radiator professionally to clear internal impurities and scale.
2)EGR System Overhaul: Cleaned the EGR pipe and found the EGR valve unit completely blocked with carbon. I used professional chemicals to restore flow.
3) Catalytic Converter Cleaning: Disassembled the silencer and chemically cleaned the catalytic converter, followed by high-pressure water and drying.
4)Exhaust Flow Control Valve (The "Smoking Gun"): Found this valve was stuck. This was likely the primary cause of the "heat sign" on the odometer, as it was trapping heat in the exhaust loop.
5)Thermostat Check: Verified the thermostat expansion in boiling water to ensure it was opening at the correct temperature.

Result:
I just completed a 200km test drive with the AC on 60% of the time.
- Max Temp: 194.99°F (90.5°C).
- Average Temp: 193.96°F (89.9°C).
- Performance: The car reached its destination without a single warning light or heat spike.

If you are chasing an overheat issue on a Gen 3, don't just stop at the water pump. Check the Exhaust Flow Control Valve and ensure the EGR system is completely clear. A clogged radiator can also hide its symptoms until you are under high load on a long drive but this valve (Exhaust Flow Control Valve) can "mimic" a water pump failure by dumping massive amounts of heat back into the coolant loop that the pump simply can't keep up with.

for reference, see log image which i took it from torque pro data and plotted it for your understanding.

I thought my journey would benefit anyone having similar issue. Any other suggestion for me would be highly appreciated.
Thank you,
Regards,
Asfandyar Ali (driving 150K+ mileage Prius 2010 Gen 3 in Pakistan)

 

Hi there ChapmanF,
Below is the image I get it disassembled and cleaned with the help of catalytic cleaner. The valve you see in the image was stuck and dirty and it was one of the main culprit. As a matter of fact, there is a small cap which was also damaged (just like a toothpaste tube cover) and the mechanic did replace that also. According to him, that faulty cap wasn't allowing the valve to open or close properly to allow the coolant to flow.

Can you please guide what is EHRS sensor and if you know it's custom PID so that i could put it in my torque pro to monitor again when i go back 200km this weekend.

Regards,
Asfandyar Ali