[vadsoom]

If you have the correct voltages, I would think that rules the battery, fuses and the relay in the SAM.

I would think the next test would be to clean the connections on the TCM, Shift actuator, and shift motor. There’s no guarantee that you still might have a hardware failure.

Are there any other fault codes?

 

[mercysakesalive]

Okay, that's great. Easy to understand. Sound logic.
My codes :
1. P0886 TCM Power Relay Control Circuit Low
2. N15/6 (P0886) Relay N10/10K9 (automate manual transmission relay) does not switch
3. There was one more code that I can't find right now unfortunately. It was something to the effect of a "clutch protection" code.

But I never have gotten a "clutch actuator not functioning correctly" code. From what you see would you think the problem is on the electrical side more than you'd think it was on the mechanical side (clutch actuator)?

Unfortunately, the car has been working perfectly for the past two days so my ability to troubleshoot has been temporarily halted. I don't see any point in taking out the seat and measuring voltages until I'm seeing codes again. Hopefully that will be soon. You know what I mean.

 

[vadsoom]

Yes, the P0886 indicates the power supply to the TCM has a short circuit to ground. The fault is generated if the contacts in the relay don’t relay close when the ignition is turned on. The TCM generates the code and sends it to the SAM through CANBUS.

When you turn the ignition on, you should hear a click in the relay A10/10k9 relay (in the SAM). The TCM turns it on through the blue wire on out of the TCM from a signal output on terminal 27.

If I were troubleshooting, I would see if that line is connecting to ground when the ignition switch is turned to “on.”

If it doesn’t, it’s either fuse 30, a wire is open, or the TCU isn’t triggering properly. It could still be a wiring problem, but that’s where I would look first.

If it’s always grounded (doesn’t switch) there’s probably a problem in the TCU that’s preventing it from working and probably mean a replacement TCU is needed. If that’s the case, the replacement will need to be coded to match the VIN using a Star diagnostic tools

If the line is pulled low when the ignition is on, it would make lead me think the TCU is ok and the relay in the SAM could be faulty. I would want to check the whole circuit path by looking for the grounding of the blue wire on SAM, connector C2 pin 7. That verifies the circuit path is working and points to the relay.

Does this help?

 

[mercysakesalive]

"If I were troubleshooting, I would see if that line is connecting to ground when the ignition switch is turned to “on.”" Does that mean check for continuity btwn ground and terminal 27? Did i understand that correctly? If so -- i dont quite understand where terminal 27 is...i don't quite understand what terminals are in this context actually... but i haven't had a chance to really look at the wiring diagram.

 

[vadsoom]

"If I were troubleshooting, I would see if that line is connecting to ground when the ignition switch is turned to “on.”" Does that mean check for continuity btwn ground and terminal 27? Did i understand that correctly? If so -- i dont quite understand where terminal 27 is...i don't quite understand what terminals are in this context actually... but i haven't had a chance to really look at the wiring diagram.

No, it’ll take some fiddling.

First, make sure fuses 8, 12, 19, 24, and 30 are good. Don’t just look at them, do a continuity test. If they are all good…

Drop the SAM. It’s hinged and has a release to sewing it down and can be pushed up and off the hinge.

Find a positive battery connection that’s always on and Leave your meter’s red (positive) probe on that power connection. You can use the ground stud that’s on the firewall near where your left foot would be when you’re driving as the negative (black probe) meter connection. There’s a 10mm nut on the ground stud and a few brown wires tied to it. You should be reading around 12 volts on the meter.

Don’t disconnect anything from the SAM.

Next, Locate connector C2 (N11/2) (it’s an 8-conductor connector towards middle on the side that’s normally facing up and has a single row of flat pins). Pin 7 should have a blue wire. Connect your negative meter lead to this pin. With the ignition off, you should read 0 volts.

When the key is turned the the “on” position, you should hear a relay click and be reading about 12 volts. Try starting the car and shifting to see if the TCM is triggering the signal on the blue wire.

For clarification during the test, your meter’s red lead should be on a constant 12-volt source and the negative should be on the blue wire on connector C2 (N11/2) pin 7

If there is no switching (zero to 12 volts with the ignition on) and when shifting, it would lead me to believe the TCM is faulty, (it’s not a 100% certainty because I don’t know what the logic in the TCM does internally and I can’t know what other signals your car may be experiencing). All I can tell you is that with the ignition on and the TCM working, there should be switching on the blue wire.

If it’s switching properly, listen for the relay N10/10r9. You should hear it clicking (I know it’s tough to hear with all of the other sounds the car is making). I don’t have internal schematics for the TCM or SAM, but it should be possible to trace the circuit in the SAM and replace the relay of it is indeed faulty.

Alternatively, a Star diagnostic can check all this stuff without the fiddling of soil can find someone with access to one that can have a look.

Am I being descriptive enough?

 

[mercysakesalive]

Yeah, you really spelled it out VERY clearly there. Thank you! I'm going to go ahead and run through this stuff tomorrow on the car. The car is currently functioning correctly (no codes) so I wouldn't expect to learn much but it will at least get me ready for when things malfunction. If it was decided that the N19/10k9 relay needs to be replaced, is it possible to do so without disconnecting the entire SAM? If so it might be a cheap shortcut to just go ahead and replace the relay ahead of waiting for it to fail again. I do notice its INSIDE the SAM so maybe the whole thing has to come out?

 

[vadsoom]

Technically, the SAM has “no user serviceable” parts inside because everything is soldered in place, but someone skilled could probably swap a relay if they were careful. It would definitely need to come out for service. The ribbon cables are fragile and don’t deal with multiple flexing well.

 

[mercysakesalive]

ok understood. yes, I remember now that the relays are soldered in place.

 

[the big e]

Yeah that’s why I said in my previous post that they was internal to the Sam.
On mine there are only three relays that you can replace the rest are in the sam unit.
I have a spare Sam if you need pics quick but they should be easy to find online.
If it acts up again(which it likely will but hopefully not) let us know.
I don’t mind providing pics if you need them to help out.

 

[mercysakesalive]

Thanks Big E, I have some pics if the SAM and the relay positions i downloaded from another thread

 

[the big e]

Ah ok.
Hopefully you can figure out what’s causing the issue.
I’d put my money on the tcm if it acts up again.(yes you can get used ones just make sure you match the number on the old one with the new one.

 

[mercysakesalive]

@vadsoom - The car has been working fine for the last few days. But I wanted to run through the blue wire on C2 test so I'd be familiar and ready when the car doesn't work again.

So with ignition off I'm measuring 0 volts at the blue wire on the C2 (N11/2) pin 7. And with the ignition on I'm measuring 11.5 volts at the blue wire. And with the engine running I'm measuring 13.5 volts. But I'm not measuring any voltage change when I shift from Park to Drive or Neutral or anything. I expected to see a voltage change when I was changing from Park to Drive...

My question: When the car DOES malfunction again and IF the TCM is the problem, what test result tells me that its the TCM? Is it: If I see 0 volts with ignition OFF and I also see 0 volts with the ignition ON?

 

[vadsoom]

@vadsoom - The car has been working fine for the last few days. But I wanted to run through the blue wire on C2 test so I'd be familiar and ready when the car doesn't work again.

So with ignition off I'm measuring 0 volts at the blue wire on the C2 (N11/2) pin 7. And with the ignition on I'm measuring 11.5 volts at the blue wire. And with the engine running I'm measuring 13.5 volts. But I'm not measuring any voltage change when I shift from Park to Drive or Neutral or anything. I expected to see a voltage change when I was changing from Park to Drive...

My question: When the car DOES malfunction again and IF the TCM is the problem, what test result tells me that its the TCM? Is it: If I see 0 volts with ignition OFF and I also see 0 volts with the ignition ON?

Mercy, it’s great your car has been running! The voltages you are reading seem correct, but the 11.5 volts seems low. There could be a voltage drop inside the TCU, but I would have expected it to read about the same as the battery. Of your battery is low, it can cause all kinds of erratic behaviors, including the issue you’ve observed. Definitely have the battery load tested. A meter reading isn’t enough.

The C2 pin 7 line provides the ground path for the Automated Transmission Relay coil in the SAM and is monitored by the system logic. I wish I had compete schematics for inside the TCU and SAM to be able to tell you what conditions makes the line pull low, but I don’t have the answer. I can tell you that if that line doesn’t provide the ground path to the relay, the car won’t shift properly. I have a suspicion that the C2 pin 7 line is the “failsafe” to prevent the TCU from activating the shift circuits if there is a fault. The fuse is a beefy 40 Amps - a lot more than the TCU logic needs to function, but what I would expect for the transmission shift and clutch actuator motors.

Does this make sense? Anyone else want to chime in?

 

[mercysakesalive]

when the car stops working again, I'm not clear what the troubleshooting logic tree looks like. I think its:
Is there 12 volts at the blue wire with the key on? Then the problem maybe not the TCM side of the circuit.
Is there 0 volts at the blue wire with the key on? Then likely the TCM side of the circuit is bad.
Is there a clicking sound when the key is turned to the ON position? Then the relay is likely ok.
Is there not a clicking sound when the key is turned to the ON position? Then the relay is likely bad.
Does this sound like correct logic?

2. Battery load tested and is good. Will compare voltage at blue wire to voltage across battery tomorrow. Maybe that 11.5 volts is telling me something.

 

[vadsoom]

when the car stops working again, I'm not clear what the troubleshooting logic tree looks like. I think its:
Is there 12 volts at the blue wire with the key on? Then the problem maybe not the TCM side of the circuit.
Is there 0 volts at the blue wire with the key on? Then likely the TCM side of the circuit is bad.
Is there a clicking sound when the key is turned to the ON position? Then the relay is likely ok.
Is there not a clicking sound when the key is turned to the ON position? Then the relay is likely bad.
Does this sound like correct logic?

2. Battery load tested and is good. Will compare voltage at blue wire to voltage across battery tomorrow. Maybe that 11.5 volts is telling me something.

There if you measure on the blue wire without the ignition on and the other wire of your meter to ground, you should see about 12 volts. You’ll be reading through the coil to the load side of fuse 30 to the battery. There will be a small
Voltage drop because of the resistance of the AT relay in the SAM.

With the ignition on, the same wire connecting the meter the same way should be pulled low and you should see about 0 volts.

 

[the big e]

Just curious what’s the cca and ca of the battery?
Also what is the temperature when it does this?
I’m wondering if the battery is too small for the car.
I’ve seen 11.5 on mine with my one-2 dongle when not running the engine but the car on.
Don’t forget the ground point near the Sam unit(by your left foot just under the carpet)
I just replaced the battery in mine due to it making the car do weird stuff (silver smart) while driving.
Otherwise you’ve got a wiring or Sam issue(could be dirty connection at the harness at the Sam)

 

[mercysakesalive]

Here's the voltage readings across the two battery terminals:
12.83v ... key off
12.64v ... key on

Here's the voltage readings with the black lead on the negative terminal of the battery and the red lead at the blue wire on the SAM:
0v ... key off
11.59v ... key on

So 12.64 - 11.59 means there's about a 1v drop between the battery and the blue wire. The car is working correctly currently even with that 1 volt drop.

Here's some battery specs:
Make Model: Everstart MAXX-H5
CCA: 650
CA at 32F: 800
The temperature here today is about 43F.
Battery passed load test

 

[the big e]

Ok that’s good.


It’s the same as the one I have in my silver smart which handles the car pretty well.

If the voltage drops anymore then what it’s at I would want to get the Sam unit checked as the relay could be going out.
Until then enjoy it.

 

[vadsoom]

Yep. Those are good numbers.

 

[mercysakesalive]

Car would not start today. Outside temp 41 degrees. Battery at rest was at 12.2 volts. I lowered the SAM, measured the blue wire with key on dropped to 11.2-11.3V .... a half second after I took that measurement, I turned the key all the way right and the car started.

Could be lowering the SAM jostled a wire into the correct place or could be a coincidence. Anyways, I was glad to see it failing to work again so that I can work toward having a RELIABLE car again.