Hello again. It has been a busy summer. Mary's V70 limped home with the Reduced Engine Power message displayed. 50mph max, west bound on Hwy 12 during rush hour...

It gives P2135 and P0221 codes, Throttle Pedal Position switch mismatch. Has anyone seen this problem before ? Anything to check before replacing the switch ?

Thanks

Greg

It was the throttle body. We have driven the car over 1000 miles in warm, cold, wet, dry, highway, city, etc. conditions. No problems with Reduced Power.

Greg

Next steps - Called XeMODex Friday. Told Matt the whole story and asked if I could send the TBM to them and have it checked out. He explained that some other company felt their toes were being stepped on when XeMODex was building the '04 ETB. Consequently, they quit. At this point they don't have the test stands for these units any more but if they had one left in stock, he would send it to me.

Monday morning the FedEx guy was on our doorstep with a replacement unit. +1 for XeMODeX.

The gears in the old unit had all their teeth. There was a little oil in the electronics chamber and no sign of burnt traces or components. Other than looking under the cover I did not try to disassemble the unit.

Now, if you don't hear from me in the next few days...

Greg

BTW, planning ahead I had a look at replacement ECMs. Most of the rebuilders appear to be in England or Europe. volvoecm.com is priced in US dollars, $475 to be exact. There are notes for other years so it would remain to be seen if they are applied to all units or just those years.

Installed the new gas pedal and position sensor yesterday. The car seemed to accelerate smoother when I took it for a test drive. It was ~+32°F, I ran several errands with multiple drive/heat soak cycles (most recent failure scenario) and it was fine. Mary took it to Plymouth, ~50 miles of mixed highway and city driving. Still fine. She also noted that acceleration seemed smoother.

Mechanical Musings:
Destructive disassembly of the old pedal assembly/sensor revealed an intricate pick up and a moving 'actuator' attached to the pedal shaft. The sensor is a multi layer circuit board with 2.5 cm diameter spider web of traces. One side has 80 'spokes' laid out in an even, radial pattern, the other has 80 radial traces laid out in 40 pairs. The paired leads are close together with pie shaped blank spaces between them. On an interior layer are 10 concentric rings of traces. The ends of spokes feed through the circuit board.

The actuator has 24 radial traces with connections across both ends making 2 closed cell. The new traces are connected at the top or the bottom, making 2 open ended cells. The pattern repeats all the way around the circle.

I have not idea what that gives for angular resolution. The circuit board does not show any burnt traces or obviously charred components.

The pedal assembly had noticeable play before disassembly. The pivot shaft on the pedal measured .472" and appeared to be very cylindrical. The pivot bushing in the housing measured .4765" - .4775" on the outside and .479" on the inside.

There is a big, stiff pedal return spring inside the housing.

I don't know if that level of wear in the bushing would be enough to cause the sensor to loose track of the pedal position. If it is, replacing the bushing should restore function. There are several issues that may prevent repair. 1) the pedal is very difficult to remove from the pivot shaft 2) the plastic latches that hold the case together are fragile 3) the bushing would have to be made or found 4) a new pedal assembly is $150.

If there aren't anymore problems, I'll let you know how it goes in a few months.

Greg

Nope, that's not it either.

Mary will be happy in about a week, it will take that long to build up trust in the car again.

GOOD work describing the workings of the position sensor. Some things are not made to come apart. The worn bushing just might have been the problem, if the changed angles would have an effect on the circuit boards. Mary might be more of a lead foot than you are???

Have an uneventful winter...

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Keeping it running is better than buying new

Thanks Klaus. ...might be more of lead foot... Since Mary discovered that the car ran better on premium gas she has been burning the front tires off it.

I think she is there (or she hates driving the Honda). Tomorrow she is taking it to Mpls.

It's -10°F this morning and Mary was running some errands when the Reduced Engine Power warning came on again. It may not be entirely temperature related. She was in town so it was not an issue. Went to a meeting came out and the warning was gone.

Moving up the chain of least expensive parts, I said ' I'm going to replace the position switch on the gas pedal'. Mary replies ' you know, when it first happened there was a little critch critch when I pressed the pedal down'. Meaning that she heard and/or felt something when the initial failure occurred. That's new information.

Ordered the part from Tasca and the shipping was $13.

Greg

This gets more interesting all the time...
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Keeping it running is better than buying new

I replaced the connector on the ETM and the car started!

Inconclusive results - After driving it about 60 miles I could not get the intake manifold temperature up to the same temp (87°F) as when Mary brought it home with the car home with the reduced engine power message displayed.

Greg

Changing the ETM connector-

The connector housing (9441564) is numbered 1-6, front and back, for the terminals.
The car wiring harness color of the wire connected to the terminals are:
1 - blue w/red tracer
2 - green w/yellow tracer
3 - white
4 - green
5 - brown
6 - green w/black tracer
The replacement terminals (30656679) come with a foot of wire (red w/black tracer) attached. They also have a little silicone seal around each wire that is captured by the crimp on the connector.

Cut off the old connector of along with 1/2" of the vehicle wiring harness.
Map the wire colors going into the back of the connector.
Cut 6 pieces of shrink tubing and slide them onto the new wires.
Solder the new connectors to the existing wiring harness.
Slide the shrink tubing over the solder joints and shrink it in place.
Mark the terminal end of each new wire with a strip of colored tape that matches the original wiring harness.
Wire pairs 2 and 3, and 5 and 6 are twisted pairs. You will see this when you cut off the old connector. Twist wires 2 and 3 around each other with about 1 and 1/2 turns per inch. Twist 5 and 6 around each other in the same way.
Insert the new terminals into the back of the connector. The latches are towards the outside of the housing.
Tidy up the loose wires with some of that split black flex loom.

Ben at Tasca has no idea what he is talking about when it comes to the connector for the throttle body. The connector only had 6 places for wires, not 12 (the face of the connector is numbered 1-6), the repair terminals are not crimp on, they do indeed come with pigtails as shown in the parts look up, two of the 'required' repair terminals (30656681) will not even fit into the housing, the connectors on the ends of the (4) 30656678 look identical to the (6) 30656679 terminals(which I believe are the required terminals)...

It is so nice when you can call the dealer and get useful information.

Greg

12/16/2016 update

I talked to the tech (Matt ? ) at XeMODeX and he said that it is probably the connector that is crapping out. Supposedly Volvo used gold plated terminals but the plating was not that good. The connector warms up and won't carry the required current. His solution is to replace the connector.

A rear brake line on the Honda sprung a leak, so since it is quite cold ( highs around 0°F ) Mary has started driving the V70 again. I need to find a can of cold air ( and a wired keyboard, but that is another story ) so when the car decides not to go over 50 mph she can give the connector a shot of cold and proceed on her way.

LiveChatting with Ben at Tasca I need:
30656681 terminal (2)
30656679 terminal (6)
30656678 terminal (4)
9441564 housing (1)
to replace the connector. He could not explain why I need 12 terminals when there are 6 wire positions in the housing, but, hey.

Tasca has the parts for $40 or so. The shipping was close to $50 for UPS ground. USPS was like $90. I don't know what a small USPS flat rate box costs to send but I shipped two brake caliper cores to California for $17 in a medium box. Even $50 seems like a lot to drop a ziplock full of small pieces in a box, stick on a label, and throw it in the outbox.

Our local Volvo dealer, who shall remain nameless for shame, wants $10.24 for each terminal and 2X the online MSPR for the housing. The total comes to more than the parts plus outrageous shipping from tasca.

volvopartswebstore has the same parts and the same prices as Tasca but shipping is $14. $55 and the parts are on the way in a couple days. I guess I'll see what shows up.

Greg

I have mentioned the steep shipping/handling to Tasca. Volvoparts is in Chicago, much closer to us, so the shipping time is cut in half.

Perhaps the reason for the 12 pin connector is so that when the pins wear out, you can flip it over and use the other 6 pins! Or, Volvo ran out of 6 pin connectors.

I agree with your assessment of our local Volvo dealer. The people who work in parts are so nice, it is just management that screws the customers.
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Keeping it running is better than buying new

Reseated the ECM and the car ran fine. When I checked for codes there weren't any. Seemed odd but maybe unplugging the ECM will do that.

Mary drove it and called to say the check engine light came on. It was still running so I did not think that it was fatal. But it goes to reduced power and ends up coming home on a flatbed.

Check engine light is off. No messages in the DIM window. It does have the P2135 and P0221 codes stored again. I didn't think the CEL would go off without multiple cycles without a fault.

Any ideas on how to ohm out the pedal sensor or thoughts about what else might be wrong ?

Thanks

Greg

This is long but good reading. Volvos use 5V pedal sensors, so the variable wire will go from .01V to 5V at full throttle.

https://www.obd-codes.com/p2135

My guess is the ETM is broken or the connector to it is bad. Why do companies use plastic gearing? Don't they know that plastic gets brittle with age and excessive heat will cause extra wear on plastic gears?

If Mary wants, I have a good running 855T she can borrow. It will leak a quarter size spot of oil from the RMS every time it is parked. The seat heaters work!

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Keeping it running is better than buying new

"..My guess is the ETM is broken or the connector to it is bad...."

That goofy little connector at the ETM was suspect when I was going through this. Have you taken a good at it to see if the wires are still firmly terminated within the connector or that the contacts haven't gotten pushed back, etc? Not knowing exactly how to unlock the connector from the ETM, I finally ended up snapping off both locking tabs. It's now held in with a zip tie to make sure it says firmly engaged with the ETM. Even my indy tells me that's not at all uncommon. He also said that stretch of harness from the ETM to the ECM (with new connector already attached) can be purchased separately from Volvo if yours is at all questionable.

Are you sure it was the ECM you R2'd and not the TCM? Or maybe you reseated both while you were at it?? Did you unplug and replug it in a few times, using some sort of contact cleaner, to make sure the pins were scraped clean?

If the problem continues to point to the TCM, I've got a spare one that I'm pretty well convinced is still good if you need to borrow it for a week or two as a test. You just pay postage back and forth and promise to return it :)
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Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)

It was the unit labeled Bosch 7.1. I figured that was the one that dealt with the fuel side of things. Not to mention that the XeMODeX video showed the guy removing that one. The pins all looked clean and in position on both sides.

BTW, XemodeX doesn't make an ETM for 2004 cars anymore but when i mentioned That I had bought this unit and it had a lifetime warranty they appeared ready to stand behind it. We will see where that goes. I would be happy if tehy looked at it and pronounced it 'good' or 'bad'.

Greg

Greg,

Sorry this got so long. If you want to skip the drama let me just say try removing the ECM and re-seating it.

Now for the long version if you have time to read it...........

We went through this EXACT scenario with my wife's 05 S80 2.5T. She and my son were 850 miles away and heading home the first time it occurred so I suggested to her, over the phone, to limp it into a good Volvo indy that I know in that area. They cleaned the throttle body, which it was time for, cleared the codes, and sent her on her way. The guy that runs the shop said that in all the Volvos they've ever worked on, he had NEVER seen that version of Bosch throttle body ever go bad - they just need periodic cleaning. I should have digested that comment I bit more thoroughly......

Anyway, about 200 miles down I20, it happened again. She was freaked. No where to pull over on the interstate. She found that if she did pull over, shut off the ignition and restart it, it would be fine for a while. Anyway, they finally made it home.

So I once again removed the throttle body, witnessed the perfect cleaning they had done on the throat and plate, but this time I opened up the black plastic cover and carefully cleaned the contacts with alcohol. I got a bit of carbon-ish residue off of the contacts, but not enough to say it was the point of failure. Sure enough, I replaced the throttle body and after driving it about 20 miles on a good warm day it gave me "Reduced Engine Performance" and went into limp. Turning the engine off and restarting it cleared the message and restored full power. (Heat seemed to exacerbate the problem.)

So I called my buddy back at the shop that cleaned it the first time and he said "That's really weird", and AGAIN said he had never seen a need to replace the Bosch throttle body. You'd think I would have started to get it, eh? So he said to me "Well, maybe this is the rare one. Go ahead and try a new throttle body.

About two weeks later, with a brand new $350 throttle body in place, we headed off for the same 850 mile trip in the opposite direction. About 60 miles out...... "Reduced Engine Performance". (limping again).

Another call back to my indy shop for guidance and this time he says I need to start searching upstream for a bad connection. His suggestion was to remove the ECM and reseat it so as to refresh the connections. He also said to check over the harness between the TCM and the ECM for any possible weakness. I don't have the special tool required to unlatch the ECM and my attempts to do it with a long skinny screwdriver weren't working. So I took the car to a local indy close to my house and they did it. BINGO!!! Apparently that was the problem, as it has been running fine now for about 6 or 7 months. I'm convinced I have a perfectly good used TCM sitting on the shelf now. But if my indy mechanic is right, I'll never need it.

Hmm, I'm not so excited to hear that but...

I checked all the connections and fuse but didn't clean the throttle body. I'll do that next. Once I checked the electrical side I reset the codes and took it for a drive around the block (~10 miles). It was fine. Mary takes it to Buffalo (~10 miles) and the Reduced Power message comes back. She runs an few errands, restarts it and the message is gone.

The Haynes manual has a diy tool for removing the ECM.

Greg

Gosh, I should have consulted my Haynes manual - had no idea that tool drawing would be in there. I also saw a drawing out on the Internet for a DIY tool that was like the ones out there for sale that move both locks simultaneously. I can't find it now.
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Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)

Any reason not to make a U shaped tool and release both sides at once ? 1 mm thick strap is pretty flexible stuff so I don't think the mismatch between the side would be an issue.

Haynes says the 5 mm rivet is a pivot. What is the pop rivet supposed to pivot on ?

I did remove the throttle body and it was a little oily, but nothing exceptional. I did clean it as long as I had it in my hand.

Greg

Interesting video:

https://www.youtube.com/watch?v=0oHIq7Rwlgs
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Keeping it running is better than buying new

That's a good video. You can see the little slots in which the tool pivots. I believe that what happens is that when the purple "locks" start sliding, they sort of lift the ECM or TCM upward. So if you have a tool that only slides one of the locks then you have to slide one side a bit, then the other side, back and forth. A tool that moves both locks simultaneously, like the one IPD and others sell, would be desirable. Heck, just make two copies of the tool described in the Haynes manual and use them together.

Poor Mary, that is a rough road to go slow on.

Try cleaning the Electronic Throttle Body. Be careful with the power plugs, they are fragile.

From Matthews Volvo site:
As for your Throttle Position Sensor try this out;
Turn ignition to position ll and wait,
A calibration process should be audible within about 30 seconds or so,
Wait until the calibration finishes,
Turn back to position O and wait 5 seconds and start the vehicle. This should calibrate the Throttle and might fix your TPS codes.
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Keeping it running is better than buying new

It has the Xemodex throttle body which should be contact free. I did look at their site and they have a troubleshooting guide. most of the problems seem to do with corroded connections. I'll check that.