CHECK EV SYSTEM THC D0005 Coolant Pump 1 Malfunction

[iehawaii]

Aloha,
had the known "CHECK EV SYSTEM" message. Got me TIS software and read the problem as THC D0005 Coolant Pump 1. Pump 2 has higher internal resistance than Pump 1. Pump 2 draws 2.4 Amp vs Pump 1 1.8 Amp. Both pumps look similar if not identical. Sensing cables been long enough, swapped them and transferred the error code to THC D0006 Coolant Pump 2. Deleted code, swapped cable and code is back to THC D0005. Ordered Pump 1, is available between 140 and 160 USD, will take about two weeks to get to Hawaii. So far could not get availability on Pump 2 which is listed about a 1/3 higher, think it was around 220 USD. The THERMAL ECU lists for about 400 USD and seems to be readly available. Main lesson learned: I'm OK to drive, since I know both Pumps work and one backs the other. (Tesla had a recall in the past about HV Battery Coolant Pump, and changed from a one to two pump system must be a few years back). Anybody with knowledge of this, can I substitute Pump 1 for Pump2. Any reason why Pump 2 hard to find.
Wait for some input, and still consider to buy all three items if I can get them and do some more detailed troubleshooting and testing.

 

[TonyWilliams]

I'd love to know the rational to have "redundant", but different pumps.

 

[alflash]

sorry :|

 

[dfergenson]

From my own experiences with this issue, you should be able to replace either pump with either pump or with the drive unit coolant pump. First generation Tesla Model S pumps work fine and cost about $100 on eBay.

I replaced both pumps with the equivalent Tesla Model S 2012-2016 parts and they're running two years later. I swapped my drive unit coolant pump, which had failed, out for one of the battery coolant pumps and that, too, is running two years later. So those three pumps were clearly interchangeable. Also, all three pumps had the same Bosch part number, both operate on the same voltage and have the same duty cycle programming on their control pins, and both have the same connector.

So, why would Toyota have different part numbers for the pumps? I suspect that this is for historical reasons. This car was engineered in a very short time (Wikipedia says 3 weeks from contract signature to prototype) and probably under a lot of corporate secrecy given that Tesla had not launched the Model S yet. An indication of this can be found in the placement of the onboard charger. The onboard charger has fuses inside it which is a rookie mistake by Tesla but on the Model S it's under a seat so pretty accessible. The the more experienced Toyota engineers buried it under a maze of wires and hoses (see this topic: https://www.myrav4ev.com/forum/viewtopic.php?t=2530) and removing it takes hours so most likely they simply did not know about the fuses. It's not much of a leap to assume that they did not know that the pumps were identical since the parts were probably sourced from Tesla.

 

[alflash]

From my own experiences with this issue, you should be able to replace either pump with either pump or with the drive unit coolant pump. First generation Tesla Model S pumps work fine and cost about $100 on eBay.

I replaced both pumps with the equivalent Tesla Model S 2012-2016 parts and they're running two years later. I swapped my drive unit coolant pump, which had failed, out for one of the battery coolant pumps and that, too, is running two years later. So those three pumps were clearly interchangeable. Also, all three pumps had the same Bosch part number, both operate on the same voltage and have the same duty cycle programming on their control pins, and both have the same connector.

So, why would Toyota have different part numbers for the pumps? I suspect that this is for historical reasons. This car was engineered in a very short time (Wikipedia says 3 weeks from contract signature to prototype) and probably under a lot of corporate secrecy given that Tesla had not launched the Model S yet. An indication of this can be found in the placement of the onboard charger. The onboard charger has fuses inside it which is a rookie mistake by Tesla but on the Model S it's under a seat so pretty accessible. The the more experienced Toyota engineers buried it under a maze of wires and hoses (see this topic: https://www.myrav4ev.com/forum/viewtopic.php?t=2530) and removing it takes hours so most likely they simply did not know about the fuses. It's not much of a leap to assume that they did not know that the pumps were identical since the parts were probably sourced from Tesla.

Completely agree with your descriptions and ratings.
I will add a video on how to control such pumps in https://www.myrav4ev.com/forum/viewtopic.php?p=29818#p29818

 

[dfergenson]

FYI:

plee and I verified that the powertrain pump and battery pumps are NOT compatible with the cabin heating system pump.

The connectors at least are different.

-Davio