i had a check engine light for a ftp circuitthe first image was the ftp sensor and second was the p/s switch

---

the top image is ftp sensor which was erratic and causing a code fault in ftp sensor,after checking the sensor,tightening connections to sensor,i noticed the ftp was so rapid on the scope it had to be electronic generated so i disconnected the alternator,all coils one at a time,checked powers and grounds for noise,started disconnecting sensors and switches and when i disconnected the p/s switch the concern went away.
the ps switch was cycling way faster the normal it is just a on off switch i am thinking because the cycling was so fast that it was confusing the pcm software and sending the signal down the ftp sensor circuit

i did talk to ford and at this time they cannot explain why it did this either why it only effected the ftp circuit all other circuits read normal vpwr,vref,sig rtn,all other sensors on scan tool read normal

What were the specifics of the vehicle?  year,make,model?

sorry it was 05 ford escape 3.0 v-6

fordman wrote on Jun 29^th, 2013 at 7:02am:

i did talk to ford and at this time they cannot explain why it did this either why it only effected the ftp circuit all other circuits read normal vpwr,vref,sig rtn,all other sensors on scan tool read normal

Sorry for the beginner-type question, but may I ask what is the PS switch, and these other devices:vpwr,vref,sig rtn ?

Thanks for you help!

vpwr(vehicle power), vref(vehicle reference voltage), sig rtn(signal return). Also known as reference voltage ground and signal.

Partyzan wrote on Jan 30^th, 2014 at 10:48pm:

fordman wrote on Jun 29th, 2013 at 7:02am: i did talk to ford and at this time they cannot explain why it did this either why it only effected the ftp circuit all other circuits read normal vpwr,vref,sig rtn,all other sensors on scan tool read normal Sorry for the beginner-type question, but may I ask what is the PS switch, and these other devices:vpwr,vref,sig rtn ? Thanks for you help!

PS=power steering switch--this ends a signal to the PCM that slightly raises the RPM by opening the IAC (idle air control) further, to prevent stalling the engine, when doing parking type maneuvers.

It reminds me of the old Ford EGR delta pressure sensors that would generate some kind of EMF interference & set cam sensor codes!