Solid CEL and blinking CRUISE: p0700 and p0725

2005 Subaru Legacy 2.5GT automatic: p0700 and p0725

 

There's a solid CEL and a blinking CRUISE light.

 

These codes popped up when I started the car. It still runs. The only detectable issue I have is that it idles funny at full stops when in Drive, and sometimes it'll struggle a little bit when I hit the gas. It's stalled twice when I went from a full stop to accelerating.

 

And if I punch the accelerator hard, sometimes it'll try to change gears and slow down abruptly (similar to downshifting in a manual when I meant to up-shift.).

 

I was wondering if anyone had any idea about what the problem could be.

Blinking cruise and disabled cruise are a safety measure when a CEL is triggered.

 

P0700 Transmission Control System Malfunction - a generic transmission code that is triggered when the transmission is upset about something

 

P0725 Engine Speed input Circuit Malfunction - this is the heart of the issue

Manual says "open or short engine speed output signal circuit, ECM malfuction, CAN communication malfunction"

Trouble code is engine speed not correctly received by the transmission from the ECU.

The result? Torque converter doesn't lock up

 

May be a sensor issue, wiring issue, or TCU issue

http://legacygt.com/forums/showthread.php/plz-come-if-youve-had-cel-p0725-189828.html?t=189828

Others said the issue went away after a few cycles.

 

Either way, the repair manual says

1. Check the trouble code of the ECU

Is trouble code of AT CAN communication circuit detected?

If yes - perform diagnosis according to the trouble code

If no - go to step 2

 

2. Check the trouble code of the TCU (trans module)

Is t rouble code of AT CAN communication circuit detected?

If yes - perform the diagnosis according to trouble code

If no - go to step 3

 

3. Check trouble code of TCU

Is any of following trouble code detected? Output speed sensor circuit / AT vehicle speed sensor circuit malfunction (rear wheel)

If yes - perform the diagnosis according to trouble code

If not - replace TCU

 

If you have a friend at the dealer with a Subaru Select Monitor and won't charge you, have them pull the tranny and/or ECU codes.

If not, get a VAG-COM cable off eBay, download FreeSSM and see what other codes you can pull.

Thank You So Much for your help. I'll get on that and get those tools.

this happens to my car evey time i let the car roll with the key on but engine off .. i think its a bug with subaru software i can reproduce this on any 05 lgt 5 eat car.

 

this is no longer true on a 07 lgt.

 

your idle issues .. disconnect battery .. reconnect after 1 min .. start car.. put in drive apply hand brake, block wheels and let it idle untill the car reaches operating temps

 

this is very common problems th car needs a chance to learn its idle where it should put the throttle at different temps and conditions.

this also goes for mt cars.