July 15, 2004

No Lockup for No Reason?

丹塔克

Here’s a real-life example of a problem that came into our shop. A 1998 Chevrolet pickup with a4L60-E由于没有反向的投诉,没有第二和第4档。我们认为这是一个日常工作。事实上,它通常是“肉汁”工作。我们通过扫描代码来开始工作,并找到P1870和P0300。

p1870(transmission组分滑动)可以是剥离的反应壳的结果,或者它可能是TCC问题。快速查看扫描仪上的冻结数据让我们倾向于相信P1870是由第4条病情引起的。无论哪种方式,第4号和TCC系统的原因都将在大修期间被覆盖,所以我们认为我们已经涵盖了该代码。

P0300 is a random engine misfire code. Because we don’t specialize in engine performance, we noted the code on the invoice for reference only. Both P1870 and P0300 are common codes we see quite often.

快速试验验证了投诉,我们的初步思想是该问题被剥离了反应壳样条。我们打电话给客户并收到了大修的授权。一切都很伟大,常规。我们得到了它,肯定,剥离了反应壳。所以我们做了基本的改革。

当我们到达阀门的身体 - 随着我们思想的背面的P1870的想法 - 我们跑了一个湿的空气测试,发现TCC调节器孔磨损,所以我们修理了磨损的孔。

Everything was going fine and the customer called mid-afternoon to check our progress.With the unit ready to go back in, we told him that if everything went well, it would be ready the next day. That gave us plenty of time.

下午4:30。我们用液体填满了它,准备了试驾。大约10分钟后,卡车工作和转移得很好。但是......它没有锁定。技术人员说他认为他觉得它锁定了一次。4:45下午4点45岁。没有锁定?所以我抓住了扫描仪并将其拍摄了一个测试驱动器,就像其他技术指出的那样,它没有申请TCC。我扫描代码,没有代码。我快速查看了TCC数据,并看到了车辆控制模块正在命令TCC使能:否。

这是快照 - 电影时间。在快照 - 动画上的一个快速的词:我觉得它们是诊断这样的问题的最安全方法。(如果你认为在手机上谈论手机和驾驶是危险的,你应该看看我如何用鼻子摩擦扫描仪的屏幕。)所以我拍了一个快照并将它放在商店的电脑上进行学习数据(见图1)。经过几分钟的数据看,我看到没有理由阻止它施加转换器离合器。节气门位置传感器,制动器,速度,冷却剂温度,RPM和任何其他可能导致VCM不适用转换器离合器的任何其他数据都看起来很好(见图2.)。

有点困惑,我决定去测试驱动器,并使用扫描仪的特殊功能双向覆盖并应用TCC以查看它是否工作。果然,它做了。我击败了扫描仪上的按钮,然后几次粉碎了,好像我可以教导VCM自身应用TCC。我拉过来把扫描仪放回监视器模式,仍然没有锁定无缘无故!我可以缺少什么?

我关闭发动机并再次扫描代码。在等待扫描仪检索代码的同时,我看看我们在开始工作之前写下了哪些代码:P1870和P0300。这个P0300现在引起了我的注意。正如我们众多人所知道的那样,P0300确实可以取消TCC应用。扫描仍未显示没有代码。顺便说一下,这个扫描仪是在GM软件上运行的Tech2,因此不太可能错过代码。

我站起来,开始回到商店和noticed TCC engaged. I glanced at the scanner and, sure enough, the TCC Enable went to YES. But all the joy evaporated as I felt a slight engine misfire and the TCC Enable went back to NO. I drove it for about a mile or so and couldn’t get the TCC off to return to TCC on. I pulled over and turned the engine off and scanned for codes.Still no codes。我重新启动了发动机并再次起飞,TCC启用再次又一次,我觉得有点失火,TCC enable回到了。因此,当我开车回商店时,即使扫描仪显示“没有代码”,我也表现出“明确的代码”功能。TCC enable随时立即启动了。现在我真的很困惑。为什么TCC在清除代码后会回来,即使没有报道清除代码?

I got back to the shop and made another tech get behind the wheel. I wasn’t sure if I needed another tech because I was all over the road or if I just wanted someone else to witness this bizarre event.We started the test drive by scanning for codes – again – and no codes were shown. At about 45mph the TCC Enable went to YES and the TCC slip went to 50 rpm or less, until we felt the engine misfire. At that point it seemed as if the VCM recognized the misfire and decided to turn the TCC system off to avoid more misfires. This was done without recording any codes, but the instant I cleared the “ghost codes” that weren’t there, the TCC Enable went to YES until it once again detected a misfire. I backed the scanner up in to the Misfire Graph Mode and looked to verify that what we were feeling was indeed a misfire. It was. But why wasn’t it recording any codes?

After several minutes of test-driving we determined that the software must have been written to turn the TCC off on the first few misfires without reporting and storing a code. If we continued to turn the key off and restart the engine and allowed it to go through the misfire cycle three times, it would report and store a P0300.

修复是更换火花塞线并消除失火。一旦失火走了,TCC正常工作。我们从1996-99上看过这个转基因卡车的这种情况。你可以真正追逐你的尾巴狩猎这个问题,因为一旦发动机检测到失火并转动TCC系统关闭,就会消失,没有加载TCC放在发动机上的负荷。

Just keep my experience in mind the next time you have a GM vehicle with no lockup for no reason.

Dan Tucker是Tucker在松弱,方舟中传输的所有者。和Sonnax的成员TascForce®.

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