PDA

View Full Version : PN / Gear selection



Highlander
October 16th, 2005, 09:35 AM
Hello guys,

I am having problems with my idle and today i found out the problem. It looks like my PCM is not recognizing that my transmission is in park neutral and therefore only utilizes the in gear tables for idle airflow.

I did a scanning and when i am in neutral my pcm sees 1st gear... All other gears are commanded fine... This is an A/T.

That problem "may" be related to another issue i am having. I am not being able to make the tansmission shift according to my VSS tables. I made a change and it took effect and its not taking effect anymore. but... i will be doing some more testing on that.

Any info or thoughts are appreciated.

joecar
October 16th, 2005, 07:58 PM
Questions:
a. Did you scan GM.PRND and it showed Man. 1st even if you were in N...?
b. When you select R or D, does it engage properly (i.e. is line pressure ok)...?
c. Fluid level/condition is ok...?

Various causes, related to pressure switch module:
1. Loose connector.
2. Bad ground.
3. Misadjusted shift cable (manual valve does not line up).
3. No line pressure.
4. Bad pressure switch module.