A/C compressor won't turn off

Question

Honda Insight

Honda Insight 是一款混合动力电动汽车，由本田公司于 1999 年至 2006 年、2009 年至 2014 年以及 2018 年至今生产和销售。

17 个问题查看全部

JMart @jmart69006

声誉积分: 1

1

发帖于: 昨天2026年10月30日

更多选项

A/C compressor won't turn off

This is a Gen 2 2010 Insight EX -- The compressor clutch relay is being continually energized by the ecm/pcm. It's not a stuck relay; the coil is energized whenever the car is running. The harness is fine. I've verified this is a real signal coming from the ecm/pcm. I've replaced the ecm/pcm and the same problem. The module turns on the coil 2 seconds after the engine is started. The command isn't coming from the dash control unit because I get the same even with it unplugged. The refrigerant pressure sensor measures good, as does the evaporator sensor and the cabin temp/humidity sensor. I get the same result when pulling the fuses for the MICU. The only way to make it stop is by pulling the A/C fuse or pulling the compressor clutch relay. What else makes the ecm/pcm thinks that the compressor needs to run?

回答此问题我也有这个问题

这是一个好问题吗？

是否

得分 0

添加一条评论

2个答案

Nick @nick 声誉积分: 106.7千 464 362 191 · Answer 1 · 2026-10-30T17:15:15-07:00

最有帮助的答案

Nick @nick

声誉积分: 106.7千

464

362

191

发帖于: 昨天2026年10月30日

更多选项

First thing I can tell you is if the compressor is running, it's not your compressor or refrigerant charge - if the charge were low or the compressor had an issue, there's a shutoff device in the compressor to protect it or it sheared if it hard locked to keep the engine running - that's an intentional safety measure, as well as the shaft being breakable if it seizes. If someone mentions it, let them know you know they’re full of It.

I would check your defrost settings and see if there's an issue if you have not — a lot of Hondas use the same system for that as well. Put your old ECU in as well, especially if you have it and you have not properly programmed this one.

I would look at the A/C controls - pull the controls from the car with the fuse removed, and see if it still continues to start like that and the controls are NOT installed - if it doesn't continue, there's a short in the panel somewhere - if it does, that is fine but it may be worth trying a different one to be sure. The good thing is this is a Honda so finding it will be cheap and easy and there's really not a ton of risk that the part is NLA from the manufacturer. The Honda P/N is 79600-TM8-A53. The SM can be found here: https://lemon-manuals.la/Honda/2010/Insi...

We need codes and more testing to do more then give you this basic check list, with the old ECU installed. Other common things to check is the fuse box under the dash - replace it and see if it continues as it's a smart MICU box, even if it seems fine to rule it out. Also check for codes on the ambient temp sensors and data on ECT sensor 2 if you have the right scan tool, as well as the A/C request source data sources. Get it scanned with an all system scanner, or buy one that does bidirectional control with lifetime updates unless you think you may need ADAS calibration in the future.

这个答案有帮助吗？

是否

得分 1

5条评论:

The new ecm/pcm has been programmed and allows the car to start. I'm using a GearWrench bi-directional scanner for troubleshooting. Scanner says the computer thinks the a/c is off. Could mean the ecm/pcm recognizes the dash isn't asking for a/c or defrost. Acts the same with dash controls pulled. Perhaps the ecm/pcm is running an emergency sub-routine that it doesn't report to the scanner? With the engine not running, I'm able to command the ecm/pcm to open & close the clutch relay w/ the scanner. So the ecm/pcm output is working. There's no way to do those commands when the car is running, so the relay stays on 2 seconds after the engine starts. Because the a/c & defrost dash commands are off, the vent fan is off. So compressor runs until it's a block of ice. I found a broken temp sensor wire on the engine air intake, which I thought was the problem, but it's jumpered back, but problem remains.

由 JMart 完成的 20小时前2026年10月31日

I also had pulled the fuses for the MICU, in case the ecm/pcm was getting a command from that telling it to turn on the a/c, but that didn't change anything.

由 JMart 完成的 20小时前2026年10月31日

@jmart69006 I would replace the MICU and see if it comes back. It does need to be coded with the HDS or a 3rd party scanner that can do bidirectional coding. I would avoid moving the EEPROM, code it from scratch to isolate bad coding. I would not reprogram the old one, even if you can - it might have an issue.

Your old ECU is suspect it it continues with a new MICU installed.

由 Nick 完成的 13小时前2026年10月31日

Thanks for responding. Wouldn't pulling the MICU fuses have isolated the MICU from being the problem? If the MICU was causing the issue by sending a bad message to the ecm/pcm, I'd think pulling those fuses would prevent that bad message from getting through. But the problem remained. Am I missing something?

由 JMart 完成的 5小时前2026年10月31日

@jmart69006 if the MICU has an issue it can still do the same thing.

由 Nick 完成的 1小时前2026年11月1日

添加一条评论

jayeff @jayeff 声誉积分: 552.9千 11 426 1.6千 · Answer 2 · 2026-10-31T23:17:50-07:00

jayeff @jayeff

声誉积分: 552.9千

11

426

1.6千

发帖于: 2小时前2026年10月31日

更多选项

Hi @jmart69006

Here's the A/C Compressor Clutch Does Not Disengage When The A/C Switch Is Off troubleshooting procedure from the service manual, that may help.

这个答案有帮助吗？

是否

得分 0

1条评论:

Only thing I’d add is get a set of real gauges that connect to the high/low sides (not one of those toy gauges that comes with 12oz cans) and find a P/T chart if OP checks the charge levels. I did include a bit on this but the research and prior knowledge on the way it works in cars put this way on the bottom.

由 Nick 完成的 58分钟前2026年11月1日

添加一条评论

Honda Insight

A/C compressor won't turn off

2个答案

添加你的答案