[Diy_efi] Torque converter clutch on 1226869

David Allen davida1
Mon Mar 27 17:55:13 UTC 2006

  ECM has no 4th gear input - it was originally for a THM 125C.  Has only
P/N input.  All TCC wiring works fine. Will lock with application of ground
to wire at ECM.
  I'm afraid what we are dealing with is a programming issue. The ECM was
part of a MAF to speed-density swap.
 Test light is well within ECM's current capacity.  Cold resistance of
test-light filament is 18R, solenoid is 20R.
 To further convince-  ECM controls the SES lamp (5R cold resistance) using
a driver with half the current capacity as the TCC driver.  The ECM uses ONE
output stage of a16024824 quad-driver for the SES lamp; but uses TWO stages
of same type chip in parallel for the TCC.  In other words, This is well
within the limits of the ECM hardware.

----- Original Message ----- 
From: "Tom Visel" <five10man at commspeed.net>
To: <diy_efi at diy-efi.org>
Sent: Monday, March 27, 2006 7:13 AM
Subject: Re: [Diy_efi] Torque converter clutch on 1226869

> Test light to check a driver circuit?  Glad it's your ECM and not mine.
> Any idea exactly how much current the lamp draws?
> To eliminate the possibility of a 4th gear switch or some other problem
> in your trans, you could connect your DVOM to the TCC output and monitor
> it while driving.  It should be close to charging system voltage while
> going down the road unlocked, and then less than a volt when the TCC is
> applied.  If it never sees 12V (or charging system voltage,) you have a
> power supply, wiring harness, or high-gear-switch problem.  If it never
> drops to less than a volt, you have an ECM problem.
> TomV
> Rick McLeod wrote:
> >Are you reasonably certain the drivers on the ECM board are good, maybe
that you're doing all right and have hardware issue?
> >
> >David Allen <davida1 at hiwaay.net> wrote:  I'm playing with my
6869-controlled turbo car, and trying to get the ECM
> >to control the torque converter clutch. It seems there are no numbers I
> >put in the calibration which will actuate the TCC output.
> >I have a test light on the TCC ouptut at the ECM to emiminate any other
> >external factors. Some things I have verified:
> >
> >Scan data shows the trans in "Drive"
> >Scan data shows coolant is hot.
> >Scan data indicates vehicle speed; and is reasonably correct.
> >Scan data indicates TPS is working; and is reasonably accurate.
> >No DTC's present.
> >"Automatic Transmission" is selected in the ECM calibration.
> >Test light does work when manually grouned.
> >
> >I have tried putting very "loose" boundaries in the ECM to make it lock
> >most of the time but can't get it to illuminate the light. No combination
> >of road speed and throttle position will make it actuate. The schematic
> >not indicate any high gear switch on this ECM. What can I be overlooking?
> >Thanks in advance,
> >David
> >
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