A vacuum-controlled EGR valve is easy to test with a hand-held vacuum pump (see the image). If the EGR valve opens and the vacuum holds for more than a minute, the EGR valve works. If a vacuum diaphragm inside the EGR valve is leaking, the vacuum will drop. Once the vacuum is released, the valve should close fully. Vacuum lines and the control solenoid must be tested too. In older Toyota vehicles, for example, a failed EGR control solenoid (VSV) can cause the code P0401. Replacing the VSV is a lot cheaper repair.
要换EGR Vacuum Modulator Valve。车很老了，1999 Toyota Rav4, 但半年前才在dealer做过tune up， 说是没问题。。。请问大侠们，autozone的这个测试code可信赖吗？（打电话问过firestone, 他们说autozone 的 code 不可信。。。）另外，这个零件是否必须换？
谢谢各种建议。
如果没有其他症状，按车的状况，诊断还是靠谱。这几天也在等邮寄零件。今天应该到。
如果还有屁0404，是不是有可能感应器也有问题?
没了机械控制点火， tune up还可以做什么东东?
以前有一辆98年rav4, 12万埋卖了，人家开了28万，还在开。不过也坏了好几个不该坏的零件。 其中包括spark coil, 换在10万埋时。
读code不过是接个reader到ECU上retreave error code而已，能錯到哪儿去？
另外，上网买这个东西比店里便宜很多
这家还不错，给我了part number。我就自己在网上找找吧。谢谢分享！
你听过很多EGR 出毛病的Toyota?
人工$268 + tax。 不知道大侠们觉得这个价格如何。这家修车厂是日车专修厂。我觉得他们很值得信赖
A vacuum-controlled EGR valve is easy to test with a hand-held vacuum pump (see the image). If the EGR valve opens and the vacuum holds for more than a minute, the EGR valve works. If a vacuum diaphragm inside the EGR valve is leaking, the vacuum will drop. Once the vacuum is released, the valve should close fully. Vacuum lines and the control solenoid must be tested too. In older Toyota vehicles, for example, a failed EGR control solenoid (VSV) can cause the code P0401. Replacing the VSV is a lot cheaper repair.
换过一次 Toyota的 EGR valve，非常简单。Youtube上有这种车的换法。当然也可能是真空的问题，找一截橡皮管子，接在EGR valve的真空口上，启动车后，用嘴吸一下，如果发动机没有熄火，肯定是EGR valve堵上了。不修要特殊工具，半小时换完。