My check engine light came on the other day. I pulled the codes and it is code #70, which I read in the Haynes manual that it is for the Transmission contro Unit. Prior to the check engine light coming on, the RPM needle in the gauges would go on and off.

The Haynes manual only list the code but no troubleshooting for it.

How can i further research into this?

Anyone with a Helms manual that can shed some light on this?

Thanks.

 

The Helm book has pages & pages of stuff, but it probably depends on what year.

For my '98 4cyl it goes something like this...
CEL code 70 covers about 9 different transmission trouble codes. All but one of them have the D4 light flashing it's own code at the same time. The one WITHOUT a D4 code, is "Engine Speed Input Circuit Malfunction" which sorta makes sense with your tach being flaky.

I don't have the book with me now, I've only got a list of the codes. The details of what you should do must be different for different years, so you're better off finding your own Helm book. Otherwise, get out your DMM & start checking the tach signal from the distributor, and the engine speed signal from the ECU to the tranny controller.