"Power Shift Indicator" lamp flashing very quickly during driving

Hi everyone.
So I got myself another GQ Patrol after the last one was stolen.
This time she's a 1991 TD42 auto.

Very happy with it but it's taking a little while to sort through the various issues. I've had quite a few issues just on the auto transmission. The last issue I've sorted was that it wanted to jump through the gears really quick and would labour a lot. I traced this to a faulty speed input signal to the TCU (on pin 23) coming from the "combination meter" (i.e. speedo cluster). Had the speedo cluster reconditioned (dry solder joints, a few capacitors replaced) and sorted that.

I thought that would sort all issues but I'm still getting the "Power Shift Indicator" lamp flash on and off very quickly during driving at say 1/2+ to wide open throttle. I know that it's either TCU related or the inputs to it from the wiring diagram. I just wanted to know if anyone has ever seen this before? And did you resolve it?

Maybe a related issue is that it jumps back and forth between gears at similar throttle position (inc. 1<->2, 2<->3 or 3<->4 depending on what I'm doing). Of course, I just select lower of two gears and this 'swapping' issues resolved but it is annoying that I have to. When I tested the TPS previously it seemed to be working within spec.

I just want a head start as I've been unable to replicate without being moving, and I don't really want to be messing around with a multi-meter into the TCU when I'm on the freeway!!

Thanks, James

James, I'm not familiar with the GQ but the flashing on the Power/Hold button in a GU indicates trans fault codes.
The workshop manual should help you translate them if, in fact, the GQ has that function.

Quote:

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Originally Posted by jff45

James, I'm not familiar with the GQ but the flashing on the Power/Hold button in a GU indicates trans fault codes.
The workshop manual should help you translate them if, in fact, the GQ has that function.

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Hi John. At startup the power indicator flickering can indicate fault codes on the GQ auto but this flickering power indicator light occurs when driving, not at startup.

I have done the procedure in this pic Attachment 69993 just to be sure but the transmission self diagnosis shows no faults unfortunately (all 10 judgement flickers are the same).

Thanks for the suggestion.

I had a similar problem with my Tb42, series 1 gearbox. Mine kept jumping on/off with the Torque converter lockup. The auto specialist tried everything. I found out that the box relies on three inputs: tps, road speed and temperature. Sounds like you've got the first two sorted. Have you looked into the temp sensor?

>>>tappin from tassie

Hey taslucas.
No - I didn't check the temp sensor...didn't seem like an obvious thing to check....I'll do that this arvo and report back.
Cheers

Apparently the box won't lock up the Torque converter unless the temp is warmed up so that made sense for my issue but maybe not for yours as it's happening in the gears.

>>>tappin from tassie