CAGS, upshift indicator, mileage computer
Thread Starter
Instructor
Joined: Mar 2008
Posts: 148
Likes: 0
From: Rindge NH
CAGS, upshift indicator, mileage computer
..is there a common link among the three? Sometimes they work, sometimes they don't. Mileage computer shows 0 instant, 99 average. Reset will display either 51 or 25.6 then revert back to 99.
When CAGS/upshift work (ZF6), so does the mileage computer.
Idle speed sometimes seems related too. Sometimes it'll idle at 2300, sometimes 1200, sometimes 400-500.
I can't find anything specific in the shop manual or by doing a search (although I could be searching for the wrong thing). Car isn't throwing any codes.
Any ideas on were I can start looking? If it weren't for the idle problem, it wouldn't bother me too much.....
When CAGS/upshift work (ZF6), so does the mileage computer.
Idle speed sometimes seems related too. Sometimes it'll idle at 2300, sometimes 1200, sometimes 400-500.
I can't find anything specific in the shop manual or by doing a search (although I could be searching for the wrong thing). Car isn't throwing any codes.
Any ideas on were I can start looking? If it weren't for the idle problem, it wouldn't bother me too much.....
Burning Brakes
Joined: Oct 2004
Posts: 898
Likes: 1
From: Pearland Texas
I don't think they are related. Try and climb under the car and disconnect the CAGS at the transmission and see if it reacts the same. The light will display, but it wont actually shift to third.
Thread Starter
Instructor
Joined: Mar 2008
Posts: 148
Likes: 0
From: Rindge NH
I found the common link.
ECM
I traced some of the high idle to the EGR valve (doesn't hold a vacuum when applied with a hand vacuum pump), disconnected the vacuum line, and the car idled normally. But CAGS/fuel mileage/upshift didn't work.
Normal idle was short lived. Went back to idling high, 2300. I tried to get the ECM into diagnostic mode to reset the IAC to unplug it (run on base idle until i found the problem) but IAC would never reset. I started searching on ECM here, instead of high idle, IAC.....
Reading some of the threads started to confirm my feeling about the ECM. Took the car into the dealer. Their test equipment wouldn't communicate with the ECM. Some back door methods of scanning revealed an internal ECM fault.
Just finished putting an ECM in - everything works normally.
ECM
I traced some of the high idle to the EGR valve (doesn't hold a vacuum when applied with a hand vacuum pump), disconnected the vacuum line, and the car idled normally. But CAGS/fuel mileage/upshift didn't work.
Normal idle was short lived. Went back to idling high, 2300. I tried to get the ECM into diagnostic mode to reset the IAC to unplug it (run on base idle until i found the problem) but IAC would never reset. I started searching on ECM here, instead of high idle, IAC.....
Reading some of the threads started to confirm my feeling about the ECM. Took the car into the dealer. Their test equipment wouldn't communicate with the ECM. Some back door methods of scanning revealed an internal ECM fault.
Just finished putting an ECM in - everything works normally.
