2004 Volvo XC70 codes P0740 and 2x P0700

melmaclifeform · Post by **melmaclifeform** » 01 May 2020, 18:42

Hey all,

A few months back I purchased an XC70 to drive while I attempt to piece together my S70, and it's been great until recently where it's given me a bit of trouble.

Recently on a highway trip, it was shifting quite hard and the DTC came up with a "Transmission Service Required" message along the check engine light came on. I went and had the codes read and up came three codes- P0740, P0700, and P0700 again. Upon researching the codes, I'm pretty sure it means that I need to have my TCM repaired. What do you guys think?

Post by **RickHaleParker** » 03 May 2020, 12:23

P0700 = "Transmission Control System Malfunction" rather vague and many things can trip an P0700 including a P0740.

P0740 = TCM-002F = Lock-up function. Slipping or not engaged.

Pull the connector to the TCM, clean the contacts, check for wiring defects. If that does not do the trick most likely you are dealing with a mechanical fault in the transmission. However before breaking out the wallet I would do a transmission fluid and filter change. Mechanical fault in the transmission is based on the assumption the fluid and filters are maintained.

melmaclifeform · Post by **melmaclifeform** » 03 May 2020, 17:04

Ok, sweet.

If it isn't that, here's to hoping it's a solenoid or something cheaper :/

Post by **E Showell** » 04 May 2020, 05:54

Rick - don't you have to crack those trannies open to get at the filter?

Post by **RickHaleParker** » 04 May 2020, 07:28

E Showell wrote: ↑04 May 2020, 05:54 Rick - don't you have to crack those trannies open to get at the filter?

You Spoiler

Disassembly required. He would be best off trying just a fluid change.

Post by **RickHaleParker** » 04 May 2020, 07:45

melmaclifeform wrote: ↑03 May 2020, 17:04 If it isn't that, here's to hoping it's a solenoid or something cheaper :/

If it not the connector, you need to get a Vida-Dice scan or a scan from a better reader.
The codes your reader is producing are questionable. It is possible it is a sensor that prevents lock-up. The reader you have may not be reading all the codes or mistranslating the DTCs.