4-way valve

[muhannadae]

Hi all,
what is the right method to know if the 4-way valve needs to be replaced on MY20 PHEV?

 

[nrayanov]

That's the last resort, and there are a few other steps you need to accomplish before you are sure you need to change the 4-way valve. Also, it's important to understand if it doesn't heat at all, heats slowly, and if there's a difference when heating with the engine being off and on.

Let's go through some steps:

1. There could be stuck airflaps. To reset/fix this, you need to put the car into ACC2 mode, push AUTO on the HVAC controls, and then press the MODE button 20 times, pausing for about 5 seconds between each press.

2. If this doesn't help, the cabin temperature sensor might be blocked with fluff/dust, and/or other stuff. It's located behind the gashes on the dashboard near the steering column. You can clean that with a compressed air can.

3. The cabin heater matrix might be blocked. You can check on YouTube to learn how to fix this or find a garage to do it for you.

4. The 4-way valve might be blocked. You can check on YouTube to learn how to fix this or find a garage to do it for you.

5. If none of the above fixes the issue with heating, you are probably looking at a broken electric heater or electric pump, especially if it heats fine from the engine.

6. If all of the above are done/fine, then you can replace your 4-way valve.

 

[muhannadae]

That's the last resort, and there are a few other steps you need to accomplish before you are sure you need to change the 4-way valve. Also, it's important to understand if it doesn't heat at all, heats slowly, and if there's a difference when heating with the engine being off and on.

Let's go through some steps:

1. There could be stuck airflaps. To reset/fix this, you need to put the car into ACC2 mode, push AUTO on the HVAC controls, and then press the MODE button 20 times, pausing for about 5 seconds between each press.

2. If this doesn't help, the cabin temperature sensor might be blocked with fluff/dust, and/or other stuff. It's located behind the gashes on the dashboard near the steering column. You can clean that with a compressed air can.

3. The cabin heater matrix might be blocked. You can check on YouTube to learn how to fix this or find a garage to do it for you.

4. The 4-way valve might be blocked. You can check on YouTube to learn how to fix this or find a garage to do it for you.

5. If none of the above fixes the issue with heating, you are probably looking at a broken electric heater or electric pump, especially if it heats fine from the engine.

6. If all of the above are done/fine, then you can replace your 4-way valve.

Thank you for taking the time to answer this.
the case is: that there's a difference when heating with the engine being off and on.

 

[macaulays]

I have a similar issue with a UK MY16 4h where engine heating appears to work fine, it heats quite swiftly (albeit doesn't get particularly hot, certainly not as hot as our other car but still serviceable) but on electric heating creates no heating or such a low level that I can't detect it!

I presume that if (like the OP and myself) you have heat when the engine is running, that would suggest that parts 1-3 above (flaps, sensor, matrix) are okay? So you are then looking at either a 4-way valve issue or an issue with the source of the electrical heating? Is the pump element referred to separate for the two heating circuits i.e. could heat be circulated fine for engine-sourced heat but not for electrically produced heat as a second/other pump was faulty?

Is there any diagnostic process an owner could undertake in relation to either 4-way vale, electric heat source or pump operations or would they realistically all need a garage familiar with hybrid systems to take a look?

I have seen references online to there also being a filter of some sort near the back of the engine bay that can get blocked and may need cleaned but I'm not sure if this filter would affect all heat getting to the cabin (from electric or engine source) and therefore wouldn't be relevant if you have engine heating of some level?

Any thoughts most appreciated!

Sandy

 

[nrayanov]

Just follow the steps above, folks

It's usually #3 or #4 in my experience.