Overdrive disable/Traction control FUSE BLOWING

[Rifleman@LaymansPC.com]

2004 V6. As stated in the title, my fuse keeps blowing on the overdrive disable and traction control. I have checked what wiring I can for bad grounds and the likes and been unable to turn up any wiring issues. I moved to a higher rated fuse in an attempt to go ahead and force the offending module to fail to no avail.

The fuse blows whether the overdrive or traction control switch are used or not.

I moved up one more level on the fuse and had no issues with it burning until yesterday on my way back from Akron. I was playing on some of the twisties in western PA with a Caddy CTS, we were hammering down off the side of a BIG mountain and I was back and forth between D5 and D4 repeatedly for the engine braking on turns and torque coming out of them into the straights. Car worked flawlessly. I noticed after that, when driving in D5 at 1700-1800 RPM, I'd step on the throttle lightly and felt what at first I thought it was a miss, but it didn't feel quite right for a miss, upon driving a bit farther I determined if I let off the throttle slightly, it would stop, if I stepped on it a bit harder, it would shift from 5th to 4th.

Today I was out and noticed when I would go to D4 it again was inoperative. I checked the Traction Control disable switch, it was non-functional as well. I assume fuse again.

Any advice on where to look?

 

[LS4me]

2004 V6. As stated in the title, my fuse keeps blowing on the overdrive disable and traction control. I have checked what wiring I can for bad grounds and the likes and been unable to turn up any wiring issues. I moved to a higher rated fuse in an attempt to go ahead and force the offending module to fail to no avail.

The fuse blows whether the overdrive or traction control switch are used or not.

I moved up one more level on the fuse and had no issues with it burning until yesterday on my way back from Akron. I was playing on some of the twisties in western PA with a Caddy CTS, we were hammering down off the side of a BIG mountain and I was back and forth between D5 and D4 repeatedly for the engine braking on turns and torque coming out of them into the straights. Car worked flawlessly. I noticed after that, when driving in D5 at 1700-1800 RPM, I'd step on the throttle lightly and felt what at first I thought it was a miss, but it didn't feel quite right for a miss, upon driving a bit farther I determined if I let off the throttle slightly, it would stop, if I stepped on it a bit harder, it would shift from 5th to 4th.

Today I was out and noticed when I would go to D4 it again was inoperative. I checked the Traction Control disable switch, it was non-functional as well. I assume fuse again.

Any advice on where to look?

If sliding the shifter over to D4 doesn't engage D4 (still says D5 in the window) it is most likely the shifter. Mine did that on our 2000 V6 years ago. It seems a diode in the shifter burns out. Mine was replaced under warranty and it worked fine until I replaced it with the SST shifter. Mashing the pedal in D5 should always illicit a downshift.

I can't see any relationship between the shifter issue and the TC. What do you mean "non-functional"?

 

[Rifleman@LaymansPC.com]

If sliding the shifter over to D4 doesn't engage D4 (still says D5 in the window) it is most likely the shifter. Mine did that on our 2000 V6 years ago. It seems a diode in the shifter burns out. Mine was replaced under warranty and it worked fine until I replaced it with the SST shifter. Mashing the pedal in D5 should always illicit a downshift.

I can't see any relationship between the shifter issue and the TC. What do you mean "non-functional"?

Both operate on the same fuse.

By "I checked the Traction Control disable switch, it was non-functional as well." I meant that when you press the button to disable the traction control the little light didn't come on inside the button to indicate it was off, a quick mash of the throttle verified that it is indeed still enabled (default).

Upon inspection it is the fuse that has once again blown (#15 I think it was in the central cabin fuse panel). With the V6/Auto (non-sst), from my understanding (and by the way it operates) D5, D3, D2, and D1 are all controlled by physical position of the shifter and the D4 is an electronic control similar to the "Overdrive Off" button found on many of today's automatic transmissions. If the fuse blows, only the "overdrive off" operation of the D4 position (D1, D2, D3, and D5 all operate as they should) and the 'traction control disable' button cease working. Leaving me with a transmission shifting all the time on the hills and turns due to lack of D4 and the inability to turn off the traction control (as is required on many of our steeper hills that are a little bumpy).

 

[LS4me]

The shifter is actually very simple. There is only Ds 4 & 5. They will give you 1-4 0r 1-5 respectively. The other positions will only give you the selected gear; i.e. select "1" and only first gear is available. The transmission will not up-shift at red-line, it will just stay in 1st. "2" and "3" operate the same way. There is no "overdrive" in the conventional sense. The Ls uses a 3-speed trans with an overdrive. There are actually 6 speeds available (all 3 can be "overdriven"), but, IIRC, only 1st and 3rd use the "overdrive". Again, IIRC, the ratio of the second gear overdrive is too close to 4th to be of any use. The gears mentioned may be wrong, but the principle is the same.

I still say the shifter is bad. Sounds like there is a short somewhere in the TC wiring; possibly the switch.

I found it. From the guy that wrote the transmission calibration:

The transmission in the LS is really two transmissions in one housing. There is a two speed in front and a three speed in back.

First gear has both the front and rear transmissions in low gear.

Second gear shifts the front transmission to high and leaves the rear transmission in low.

Third shifts the front transmission back to low and the rear to second.

Fourth leaves the front in low and the rear shifts to high. Both front and rear are now in 1:1 ratio.

Fifth shifts the front to high again and leaves the rear in high.

From the above you can see that changing the overdrive ratio (the front transmission) affects second and fifth gears. Changing the rear three speed ratios will change all the ratios except fourth and fifth.

Having all the gears in mesh all the time does affect the efficiency, but not all that much. It is the same for almost all automatic transmissions.

A bigger effect on efficiency is bands vs. clutches. Bands release with less drag than clutches, so a transmission that has more bands and less clutches is more efficient. This transmission replaces three clutches with bands and is near the top in the industry for efficiency.

And:

There are two gearsets in the 5R55N transmission. In the front is a single planetary system with two ratios, 1:1 and 0.71:1.

In the rear is a dual planetary system. This is two planetaries tied together to give three ratios, 3.22:1, 1.55:1, and 1:1. This type of arrangement is commonly called a Simpson gear set.

 

[Rifleman@LaymansPC.com]

This is just a fuse that is blowing.

I get proper/correct/flawless/perfect operation of D1, D2, D3, and D5 with the fuse blown.

When the fuse blows the only two things that do not function is D4 and the button that disables the traction control. That is the way it should work.

I replace the fuse, both D4 and the button for disabling traction control work properly (until the fuse decides to blow again which is rather frequently).

The question is, has anyone seen a similar malfunction or have any of the diagnositc/pinpoint test documents for this system?

 

[LS4me]

A bad diode in the shifter assembly can cause a short blowing the fuse. IMHO, the key here is the unavailability of D4. When my shifter went bad I select D4 but the window would still show D5 and D4 would not engage.

 

[Rifleman@LaymansPC.com]

I'm not disputing it's the shifter, I just wanna test it if that's the case. I don't replace parts on a whim. Anyone know of any schematics or the load and resistance levels for the non SST shifter assembly?

 

[joegr]

My schematics don't show any diodes in the switch assembly, but they are not always complete.
They do show one fuse in common with both the traction/advancetrac switch and the D4 switch. It is labeled F2.15, and is a 5 A fuse. It feeds the following:

Pink/orange spliced to pink/black wire to pin 7 of the transmission selector. From there it comes back out on pin 6 as a white/green wire that goes to pin 41 of the PCM.

Pink/orange spliced to a pink/white wire going to pin 3 of the traction switch. It comes back out of pin 4 as a white/violet wire that goes to pin 38 of the ABS module.

The wiring diagrams don't show it going anywhere else.

You could unplug the traction control switch and drive a while and see if the fuse still blows. That would eliminate or confirm the traction switch as the issue.

 

[Rifleman@LaymansPC.com]

Thanks Joe, will try and get into it in a few days and shout back with results.

 

[Rifleman@LaymansPC.com]

Well, I got my goal. By stepping up the fuse hoping the offending part would fail I believe has worked. Now I just have to trace out the failure (hopefully I didn't just burn up some wires but all the wires in a car should be sufficent for 10A without melting).

Upon inspection I found that this time it wasn't the fuse that blew. So after I test the wires for a bad ground (to see if any have melted), what would be the next step? Where is the module that controls the traction control and the D4 for the shifter? Is it part of the PCM or is it just a module that feeds data to and receives signals from the PCM? Anyone have any diagrams or service manuals that have the info for the non-SST shifter and plain jane traction control?

 

[joegr]

Well, I got my goal. By stepping up the fuse hoping the offending part would fail I believe has worked. Now I just have to trace out the failure (hopefully I didn't just burn up some wires but all the wires in a car should be sufficent for 10A without melting).

Upon inspection I found that this time it wasn't the fuse that blew. So after I test the wires for a bad ground (to see if any have melted), what would be the next step? Where is the module that controls the traction control and the D4 for the shifter? Is it part of the PCM or is it just a module that feeds data to and receives signals from the PCM? Anyone have any diagrams or service manuals that have the info for the non-SST shifter and plain jane traction control?

You'd better hope that it was the shifter switch, or the traction control switch, or shorted wiring. Otherwise, the only two modules involved are the ABS (the whole assembly with the electronics, the valves, and the pump) or the PCM. My previous post gave all of the detail available for those circuits. If there were other modules involved, I would have said.

Okay, I assume that both D4 and Traction-off aren't working, but the fuse is not blown? Most likely, this does mean that a wire has melted. Start troubleshooting by locating the pink/orange (pink wire with orange stripe) that leaves the fuse block. Use a voltmeter to verify that it has +12.6 or so volts on it. (The key does not need to be on.) This wire runs to some point where it is spliced to two different wires, one for the traction switch, and one for D4. Since you lost both functions, the failure should be somewhere before you get to this point. (See prior post for wire colors and function.)

 

[Rifleman@LaymansPC.com]

Good sign, traction control and ABS are still working, so the ABS module isn't blown.

I sort of hope the issue is within the PCM, it would be the third time to the shop for a PCM related issue. It has the 8/80,000 warranty. I'll start tracing the wires this weekend time allowing.

 

[Rifleman@LaymansPC.com]

Well, it will be a few days until I can get into it.

Our Cougar ate a deer...

We just sold it and purchased a 2002 35th Anniversary Edition to replace it. #188 of 3000. It's been well cared for and has VERY low mileage (8080 mile per year average).

Even with it's great care and low miles, it has a couple issues to address before my better half (the wife) starts driving it daily. So she is in the LS until I take care of things with it. Leaves me little time to look into it.