Check engine light on, P1116, P1121, P1123 codes

Which coolant pump? There are four of them.

 

Check and see if the inverter coolant pump works. Open the hood and remove the cap on the inverter coolant tank- and check the level (it's towards the back of the engine bay and on the driver's side of center). Put the car in Ready mode then go look at the coolant in the tank- it should show turbulence and move around if the pump is working properly.

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Thanks!

Is there an easy way I can check for it, or do I have to take it to the shop?

 

Thank you! I opened the cap, turned on the car and when the engine came on, there was some shaking in the fluid. But otherwise, I don't detect visible turbulence when the engine is not running. Here is a video of what I see:

The level is a little below Max, it's just about where the top container seam joins the larger bottom part of the container, definitely above the Min mark.

The Check Engine light has been off for days now, The Torque app test results are all green (good), but the Torque app still shows the P0A93 code.

P.S. Just came back from a drive, and according to Torque, Coolant temperature was around 180-187F at the highest, with MG1 Inverter getting to about 176F and MG2 Inverter getting to about 182F. No Check Engine light.

 

te shop would have to run tech stream and use the bleeder tool. is it a toyota dealer?

 

Your pump is not working. Change it out. Get an OEM pump from the dealer and it should be good again for 100,000 miles. Aftermarket units vary from 6 months to a year, sometimes longer.

 

But if it wasn't working, shouldn't the Check Engine light be on?

Also, shouldn't the coolant temperature be getting above the 180s F and also the temperature readings for the MG1 Inverter and the MG2 Inverter?

 

Try touching the inverter coolant pump with a finger or a pencil/stick, and you should feel a vibration.

First scan for OBD2 codes (DTCs) and post anything new here, then clear the DTCs (OBD2 codes) and report if anything reappears.

 

Thanks! I turned on the car and when the engine stopped, I could hear a periodic sound like a pump from the passenger's side of the bay, and while it was running, it felt that the hose to the coolant container was vibrating. While the engine was running, it also felt as if the coolant pump at the bottom of the driver's side of the bay was slightly vibrating, but once the engine stopped, I could no longer feel vibrations.

I cleared the P0A93 code that may have been there since the last time when the Check Engine light was on and after searching for new faults a few times, nothing came up.

Test Results also came all good after multiple cycles.

Thank you all for the input! My hope is that it's nothing but a glitch.

 

No, there is no code for the pump not working. The closest you will come is a code that is thrown when the inverter temperature gets too high. That code is P0A93, which you had in history and cleared below.

Only if you were driving the car hard. This could be a highway drive at 60+ MPH or a hill climb. Generally, the car will not over-temp when driven on surface streets below 40 MPH. You can continue to monitor these gauges to help you keep the car in a safe operating zone.

Nothing wrong with hope, but it is not a strategy. I'm confident you will see the code come back in the right circumstances. Even so, I'd be getting in a new OEM pump and changing it out seeing as your current pump has failed.

 

Thank you! You are right.

I just took the car out and drove it harder, uphill. The Check Engine light came on, just about when the MG1 Inverter showed about 210F and the MG2 Inverterwas getting close to 220F, according to the Torque app. I am attaching screenshots.

The test that has issues, but I am not sure what they mean exactly or if it's a cause for concern:

Test incomplete or dependent test failed
MID: $01-T1D:$8e
02 Bank 1 Sensor 1
and also
MID: $3d TID:$ca
EVAP Monitor (0.020')
....

 

The P0A93 is only pending at the moment, which is why there is no MIL (aka CEL) for that.

As far as the emissions tests go, I'd not worry about it right now, especially if you recently disconnected the 12V battery for any reason.

Also, your Torque app is not set up correctly for Prius. Those 'MID: $3d TID:$ca' strings should say the correct Toyota Prius DTC. If you are using the Torque (the free) app, you need to spend the $5 (or whatever the price is now) and upgrade to the Torque Pro app. I don't think the free Torque allows you to set up the Prius PIDs.

Other users prefer other apps like Dr Prius and Hybrid Assistant. YMMV.

 

Those last two screenshots are just a different area of the app, where it shows monitor test results rather than DTCs. The MID and TID values are monitor and test IDs. The app is working fine.

Those screens just aren't adding any information we need for the OP's current problem. The monitor tests are all showing green, except for the EVAP ones that haven't run yet. Monitor test results get cleared whenever codes are cleared, and they show as 'incomplete' until the next time the monitor runs. The EVAP monitor tests don't run until the car has been turned off for several hours (at least that's when Gen 3 does them). People sometimes post "what's the noise my car was making when I went in the garage in the middle of the night?"

 

I feel like those MID and TID codes should be translated/interpreted to something meaningful. But that is just a WAG, from what I've seen others post. However, I don't use the app myself so I could be wrong. It wouldn't be the first time.

 

Translations are being shown on the following line.

 

Just wanted to thank everyone for all the help, again.

I took it to the shop with all the information I gathered here and from the Torque app, and based on it, they spent some time testing and confirmed that the new OEM inverter pump is malfunctioning. They replaced it under warranty and now all is great again with the car.

Now that the pump is working correctly, the main difference I notice is that both the MG1 Inverter and the MG2 Inverter are showing much lower temperatures, hovering about 100 degrees F, while before they were about 180 F under normal driving conditions and up to 220 F going uphill.

The regular Coolant gauge in the Torque app is still at about 185 F under regular driving conditions.

 

Hello,

First time posting.

Firstly, I want to thank @ChapmanF, @SFO, and all the amazing, generous people on this site for the detailed explanations and workup guides.

I recently had to replace my coolant valve with P1116, P1121, and P1123. While following the workup guide, I reached a section (05-228, pg. 452) that suggested checking the resistance levels of wires WBAD, VC, and E2 in the loom between the connector in the engine bay, (W5-5, W5-4, and W5-6), and the two connectors at the ECM (E7-20, E4-18, and E4-28) on passenger interior. The specified condition suggested resistance levels below 1 Ohm for each wire. Do this check if you have P1121 plus another P112x DTC.

P1123:
To diagnose, I disconnected the 12V battery, the connector at the coolant valve (W5), and the two ECM connectors (E7 and E4). Then, I ran a wire from the engine bay to the interior to test the three wires, WBAD, VC, and E2 using a multimeter. I found resistance values in the 100 kOhm range for all three. Additionally, moving the engine bay connector (W5) around while measuring resistance seemed to fluctuate the reading on the multimeter. Out of curiosity, I went to my local salvage yard to perform the same test on a few Gen 2s and found the same issue. So maybe this is a common Gen 2 issue, and the reason simply swapping out the coolant valve never lasts for anyone?

Determined, I pulled a section of the loom from the coolant valve connector to the fuse box from a donor car. Then on my own Prius, I cut out the same section and spliced in the section from the donor car. Now the wire resistance values measured 0.8 Ohms, and that made P1123 go away.



NB: I measured a large resistance value in the 500 kOhms range between E2 and VC on every Prius I found including my own. Did not make sense when I checked the schematic. There must be something in the loom that bridges the two wires.

P1116 and P1121:
I had to make a guess here. The workup guide suggests that P1116 will occur when there is no temperature change (1 degree or less) at the coolant tank outlet temperature sensor. Meanwhile, P1121 may come up when there is a clog in the coolant system. I guessed both of these issues were related and caused by a stuck coolant valve.

For the repair, I flushed out the old engine coolant with distilled water three times to eliminate any particulates in the coolant loop. Then, I replaced the coolant valve with a new one from Amazon. After installing the new valve, I removed all the water and replaced it with engine coolant. I should mention that it took some time to get all the water out and burp the system. P1116 and P1121 solved.

So what now? Counting the days to see how long the repair lasts... I will report back when the new valve fails. In the meantime, I thought you nice people might find some of this interesting.

 

Hello!
Thank you for your research. I have the same codes on my 2007 Prius which is at 95k miles. What tools did you use for this repair? Also, why are you confident the valve will still fail? It seems like you unstuck the valve and changed the wiring.