Transmission Issue & Engine Stalled, '00 V70XC SE w/ 130

[txt00]

'00 V70XC SE with 130 kmi.

Here is a complete post in another forum and Thanks to JRL for his inputs: http://www.volvoxc.com/forums/showthread.php?t=12100

Here is the description of the problem:

Flashing arrow and CEL came on the other day. I think the car is currently in limp mode and stuck in 3rd gear. I drove home for about 20 miles at 55+ mph without any problem. While stopping that the light, the car kept lurching forward even though brake was applied.

Here are the problems:
1. At stop light, keep lurching forward even though brake was applied. Engine will stall (not stall in N or P).

2. OBDII scan reported codes P0740 (TCC circuit malfunction), P1618 (Manufacturer Contrl, Aux. Inputs, Aux. Outputs), and P0422 (Main catalyst below threshold)

3. The next day, restarted engine, clunk noise when shifted to R, and stalled when put in any gears (R, D, 3, 2, 1)

4. Can be driven sometimes and gear changing could only be done manually (i.e. manually shifted to 1, 2, 3, or D gear) but will shake and lurch upon applying brake to slow down to a stop.

5. Some AT fluid leaked at tranny/engine mating surface with AT fluid smelled like burnt fluid

Troubleshooting Performed:
1. Cycled PNP switch 15-20 times with shifter while engine was on and brake applied

2. Checked solenoid resistance with digital multimeter at gearbox connector at leads 21 (S1 solenoid), 22 (S2 solenoid) and 23 (SL solenoid). All came back about 15 ohms (specs 10-15 ohms). Is this a correct method for checking resistance?

Per this link (www.volvo-forums.com/t9850-transmission-aw50-42.htm), code P0740 is for a lock-up solenoid SL. Any ideas to troubleshoot further?

I am thinking about removing the valve body cover to physically check the solenoids. Is this really necessary? There is a slight chance changing AT fluid will fix the problem. Any other ideas out there before replacing the transmission? I will post this in other Volvo forum.

Per JRL suggestion, I did a drained and filled as well as replaced the PNP switch. Now, codes P0705 (Trans. range sensor circuit malfunction, PRNDL input) and P0748 (pressure control sol. A circuit electrical) appear. Engine stalled when shifted into gears (R, D, 3, 2, 1) and a "clunk" was heard when shifted into gear R.

BTW, flashing arrow disappeared after several starts, but codes and CEL still exist. Is this pressure control solenoid the same as STH solenoid. From VADIS, if STH resistance is incorrect, the control system would have to be replaced. Could someone confirm on this? Could resistance be tested at the connector at lead 24 (line pressure solenoid control signal). What about code P0705 and does anybody know what that is? Could this be PNP switch was misaligned?

[vegasjetskier]

Based on your description of the lurching and stalling along with the lockup solenoid code, it sounds to me like the transmission is either locking or trying to lock up the torque converter when it shouldn't.

I don't know what might cause this, maybe a bad solenoid or a control circuit?

[vegasjetskier]

I just found this web page:

http://www.babcox.com/editorial/ic/ic40238.htm

Here's a quote:

Solenoid valves (SL, S1, S2, STH), see top photo, sit in the hydraulic system valve housing, which is located beneath the housing cover on the transmission. Solenoid SL regulates the torque converter lock-up function, and valves S1 and S2 control the shifting. These valves are activated by the transmission control module, as is solenoid valve STH, which controls the transmission line pressure.

If there is a code found for an open circuit in one of the shift solenoids and erratic shifting (starting off in second or third gear), it is possible to replace them with the transmission in the car. I recommend replacing both S1 and S2 solenoid valves even though the ohm readings are in specification (10-15 ohms), as I have seen the solenoid valves work intermittently

[vegasjetskier]

Here's a post from a different forum. Hope it helps.

I have a 02 XC70 in my transmission shop with the problem of the tachometer constantly changing at speeds between 35 and 40 mph only at a constant speed. If you try to accelerate the car the problem goes away. We thought it was the torque converter applying and releasing and we confirmed it my removing the Transmission Control Module and connecting a voltmeter to the lockup solenoid wire to monitor the TCC duty cycle. Sure enough the TCM is constantly changing the amount of current going to the solenoid. Next we checked out the accelerator pedal position sensor by connecting an oscilloscope to both outputs coming from it. Both signals looked good. We have heard that this trans is having lots of trouble with the Valve body wearing out as well as the solenoids going bad.
The transmission designated the AW55-50 by volvo is essentially the same as the trans used in the 02 and newer Saturn Vue. GM designates this transmission as a AG23/33-5
I have contacted both Automatic Transmission Rebuilders Association and Automatic Transmission Service Group and neither one has seen this problem but they confirmed that the Valve bodies are wearing out. I sent the customer to the dealership to have the latest software installed into the TCM which fixed nothing. I obtained a scan tool(launch X-431) which was able to communicate with the TCM. I was able to watch all the parameters of the solenoids and inputs. I graphed the TCC solenoid current and it was constantly changing from 200 milliamps to 600 milliamps at the 35-40 mph range where I am having trouble. I graphed all the inputs to the TCM to see if there was a glitch in the APPS or one of the speed sensors and they all seemed ok.
I drove a 2001 XC70 with the same transmission and watched the torque converter solenoid at the same speed. The TCM Sent a constant 600 milliamps to the solenoid until you accelerate quite heavy. This torque converter slips a little at slow speeds similar to GM cars. It is a designed slip so you don't feel the converter apply. After watching the 2001 I know how the system is supposed to work but know I want to isolate the cause and I don't think I can go any further without removing the valve body first to inspect the solenoids and Valve body bores for wear. Any one else having this trouble with their XC70? This vehicle has about 96,000 miles.
I'm fairly convinced the problem is in either the valve body or the torque converter lining