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Isuzu Trooper Transmission Light Flashing no Codes Stored in PCM

raner777raner777 Posts: 3
edited February 2014 in Isuzu

Hello... 2002 Isuzu Trooper 3.5, Auto Trans, 4x4 Limited Edition... When engine is at operating temp I can turn it off wait one minute of less turn it back on and the trans light will not flash, As soon as I hit the throttle or put it in gear the trans light starts flashing.
It seems the changing of engine RPM is what is causing the problem. The trans is not in full limp in mode it has a harsh [non-permissible content removed] between 2 and 3 up shifting and down shifting but goes threw all the gears fine and runs around 2000 RPM's at 70 mph so the it's going to over drive just fine... Note: I do not have to manual shift is shifts all on it's own fine except for the harsh shift between 2 and 3 gear it it was not for that I would pull the bulb and be done with it... Here is the short version of what I have done... Checked Charging system (Battery load tested fine and alternator is good...Charging 14.1 volts) Serviced Trans ( Changed oil and filter and and fluid is topped off to the proper level)
Checked the Throttle position sensors ( Both of them working fine ) voltage is correct... Checked shift mode switch ( Its OK) Checked wires from trans connectors to PCM for continuity ( Check OK) Checked for proper voltage from trans connectors to PCM ( Reason for post) Here is where I am stumped... on the flow chart I have from All Data says B+ on pin 43 to PCM On the PCM test chart (Red Connector) from All Data it says 0 volts (key on) 0 volts (engine running) The readings I am getting are 0 volts (key on) Battery voltage (B+) (Engine Running) ONE OF THIS CHARTS IS WRONG ( Which One...LOL) Well not really LOL this Trans Light Flashing is kicking my Behind... I found a used PCM for 80 bucks, I got it to check if one was showing different readings than the other one ( Getting the exact same readings on both of them) so I have two good PCM's or two Bad ones. I'd say I have two good ones... Does any one have a manual that might shine some light on my problem... Side note the engine light is NOT ON (as I said I have no codes at all)... Thanks for any help that you can provide... RaNeR....


  • Well boys and girls it's fixed... Had to check all the wires for continuity, shorted wires, and pinched wires going to the transmission from PCM... Found the violet with red tracer and the violet with white tracer shorted to each other... Fixed the wires started it up and the trans light did not flash, Took it for a spin and the trans shifts smooth as silk...RaNeR

  • steverstever Viva Las CrucesPosts: 42,414

    Good to hear, and thanks for posting the fix.

    Minivan fan. Feel free to message or email me -

  • You very Welcome...

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