Transmission Issues(TCM)

[becdavies]

I have a 2001 Volvo XC70 given to me by a friend who moved overseas - which had just started acting up (trans seems to start off in 3rd barely going anywhere for a high rev). Took it to a mechanic who didn’t have time to look at it but did pull codes and there were hundreds - could have been old ones also - some related to TCM faulty signal missing (Error 530B). He reset the codes and they cleared. The only one coming back was that 530b. However funnily enough since he did that the transmission has been much better.
Does clearing codes actually help?
I’ve heard further that resetting the ECU can also assist some issues?
I can’t get into the tranny place for another 5 weeks so want to try all I can first.

Someone said just removing both ECU fuses for 15 minutes will reset? And will this assist trans problems?

[SuperHerman]

Start by checking the transmission fluid level and condition. Pull the dipstick, grab a white napkin or paper towel or rag and wipe the stick clean. What does the fluid look like? Next start the engine and get it to temperature with car sitting level. Check the fluid level.

The transmission on that car is known to have solenoid sticking issues which was rectified in later models. A few have had success changing out the fluid via multiple drain and fills, some have added an extra additive to help in cleaning. This may not work, but it is a first step. The process takes time as the new fluid has to wash through and clean the various parts.

You need to drive the car some and make sure the battery is in working condition. All old codes are potentially power related and the history is not well known.

You can take a picture of your rag test and post it. Prior owner may have already gone down this path. One other issue could be the B4 servo, but let us keep it to a rag test and level test for now.

There are many write ups on this topic - the drain plug is on the pan and seen from below looking up - it is obvious. It is not the plug seen from above looking down - don't touch that one!

[EngineeringBloke]

ATF level should be checked when the fluid is at operating temperature. It expands a lot when heated! And it takes longer than the engine to warm. I've seen recommendations to have 30 minutes of driving before doing this check.

Be careful as the engine will be hot. Try getting the AT dipstick out when it's all cold so you know how the stick clip works. Perhaps wear a glove.

Try to find something lint-free to wipe the dipstick, as lint can be a problem if it gets into the transmission. Don't just use a dunkin' paper napkin.

SuperHerman was referring to a bolt on top of the transmission. It is sometimes mistaken for an ATF filler hole but instead it holds the third gear together. It is a big deal if it is removed. Apparently some have been able to rotate the ring that then slips, but so much better not to go down that rabbit hole. To add ATF, you need a long funnel that will fit the ATF dipstick hole and add there. Recheck the level after any fill (at operating temperature), and add or remove as necessary.

There is a lot of discussion of ATF fluid type. I use fluid from the AT manufacturer, but there are many other choices. It is pretty hard to know which is best as few people switch between types to compare. Just make sure it is compatible with your AT.

[RickHaleParker]

The only one coming back was that 530b. However funnily enough since he did that the transmission has been much better.
Does clearing codes actually help?

Pull the electrical connectors on the ECM and TCM then clean both of them.
Check wiring for shorts and opens.

Clearing codes can help a car to run better. The Substitute value for some codes is to shutdown systems. The hundreds of codes no doubt had systems shut down. Clearing the codes brought systems back online. ... your car was running brain damaged. Or to put it another way. It have a Arm and a Leg tied behind it's back.

---------------------------------------------------------------------------------------------------------

ECM-530B Control module communication

Condition
Diagnostic trouble code (DTC) ECM-530B is stored if a communication fault between the engine control module (ECM) and the transmission control module (TCM) is detected

Substitute value
none

Possible source

• Communication problems in the CAN network
  Defective transmission control module (TCM)
  Cefective engine control module (ECM).

Fault symptoms
No response from the accelerator pedal (AP).