Vacuum line to transmission control pressure (Bowden) cable box question

[luckymike]

1. If this line does not hold vacuum, what is the resulting symptom?

2. If this line does not hold vacuum (the elbow at the box is good), is the control pressure box (part #1402700573) a 'must' replace item?

 

[195910]

I had an issue once on the 500E with a ruptured vacuum module, car still shifted fine but pulls ATF into the intake manifold.

Block the line from the module side and test again with a vacuum pump connected to the intake side, it might be a cracked line. If not, just replace the module

 

[gsxr]

1. Assuming a USA-spec model, the vacuum line is only for the cold upshift delay. If it doesn't hold vacuum, the result would be no cold upshift delay, which will eventually trigger the CEL, along with code 26 on pin 19 / DM.

2. You only need to replace it if you want the cold upshift delay to work, and/or have the CEL work properly if it's continually showing code 26.

Replacement is not fun, see my HOW-TO writeup.

Note that non-USA models have two vacuum lines, the other is to engage "economy" shift mode triggered by the E/S switch on the shift console.

 

[luckymike]

Thank you both.

Sounds like I can let this go for now. I was hoping it had a connection to my car skipping second gear. Will unplug the kickdown solenoid next.

I read your great writeup on replacement, Dave, and prefer to just deal with the code and CEL for now.