诊断8L45和8L90班次投诉：始终检查VFS电磁阀电路

Shift complaints and related shift or solenoid codes are not uncommon in the GM 8L45 and 8L90 transmissions. Sometimes these can be cleared by programming updates, so a thorough search of bulletins should be the first approach. If that does not resolve the issue, getting into the transmission and valve body is required, which will also mean reprogramming the TCM. Numerous articles and bulletins have been written and can be referred to on the PUN, TUN and individually flow-rated solenoids, so we won’t recount that here. The solenoids are not available separately from GM, and because replacing a single solenoid from a core unit would alter the PUN programming that the TCM algorithm uses to control solenoid flow and therefore shifts, any shift- or solenoid-related codes are often addressed by installing a new valve body.

在制造昂贵的决定之前，请查看七个VFS电磁电路点，该电路指向往往是罪魁祸首的另一个位置，并且可以单独解决。这些螺线管都是低流量，因为它们只是提供了移动相关离合器控制阀的流动和压力，或者在一个实例中，压力调节阀。这些相关的控制阀正在进行控制实际流动的沉重提升，以应用离合器，转换器离合器和控制主线和次要线压力（图1＆2）。One thing in common on all of these VFS circuits is the addition of a small signal accumulator piston. These little pistons are used to help control the shift feel of the specific circuit by dampening any pressure and flow instabilities that could affect the related control valve. As a result, these very active valves tend to wear the cast aluminum bore that they live within. Because these are low flow solenoids, any loss of the signal fluid through this wear path has a significant impact on the related control valves and shifts.

图1 - 典型离合器控制电磁电路

图2 - 线压力控制电磁电路

这些信号蓄能器活塞可以容易地检测磨损（图3.）。最好用仍然在活塞中的弹簧测试这些，并将测试端口打开在弹簧的中心。经验表明S3和S4位置通常是最糟糕的。在寻址这种磨损的任何潜在解决方案时的考虑因素是替代材料，并且确保诸如（铝）材料由于不同的热膨胀速率而在操作温度下减轻孔和活塞之间的任何增加的间隙。颜色编码阀体图像（图4.) and chart (图5.) identify which solenoid and signal accumulator should be considered for various shift or drivability complaints.

图3 - 真空测试信号蓄能器活塞

图4 - 8L45,8L90 VFS电磁阀和蓄电池位置

图5.– VFS Solenoid & Signal Accumulator Piston Chart
NL意味着增加电磁电流会增加螺线管输出压力和流体流动。 NH意味着增加电磁电流降低螺线管输出压力和流体流动。

VFS螺线管	TCC	2-3-4-6-8	1-3-5-6-7	4-5-6-7-8反向	1-2-7-8- 撤销	1-2-3-4-5-Reverse	线压力
目前的控制	NL	NH	NL	NH	NH	NL	NH
信号蓄能器活塞	S7	S4	S3.	S5	S1	S2	S6
压力控制（电路）	High (TCC/PTS Enable)	High (Line)	High (Line)	低（AFL）	低（AFL）	High (Line)	低（AFL）
Related Complaints	转换器应用/释放投诉;Burnt Converter	2nd, 3rd, 4th, 6th & 8th Gear	1，第3，第5，第6型齿轮	4th, 5th, 6th, 7th & 8th Gear; Reverse	第一，第2，第7档;撤销	第一，第二，第3，第4齿轮;撤销	低线压;滑动和烧焦的离合器;各种班次投诉

有时注意最小的物品可以挽救你的大美元。如果在信号蓄能器活塞孔中检测到过量的磨损，可以用改进的Sonnax活塞和弹簧恢复液压完整性。每个活塞都具有硬涂层阳极氧化和环形槽，以大大提高长期耐用性并保持复出。

• 下载ZIP阀门™：信号蓄能器活塞套件154740-06K.包括您需要快速且轻松地重新处理最多四个孔的所有组件，无需铰孔。
• 需要铰孔：Oversized signal accumulator piston kit154740-01K.包括一套完整的七个活塞，并与工具套件一起使用154740-TL.。

Maura Stafford是Sonnax副总裁传输产品。她是Sonnax的成员Tasc力量（技术汽车专业委员会），一批认可的行业技术专家，传输重建者和Sonnax传输公司技术人员。