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The 3-pin matches the description of the connector for the Clutch Pedal Position Sensor. The sensor is at the pivot of the clutch pedal.
Interesting, autoraider this car was throwing a P0807 code. Maybe that may be the source to that.
 

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Discussion Starter #22
I have looked up what a clutch position sensor should look like (white body with a 3 pin connector) and it doesn’t look like this car has one, Unless I am blind. And if it doesn’t have one, it’s not an issue to get one, but where does it mount? Is there a picture?
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If it doesn't have one the bigger question is: What was butchered to get the engine to start, since the clutch has to be fully released for the starter to energize.

This also may explain your lack of cruise control, since depressing the clutch will disengage it.
 

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Interesting, autoraider this car was throwing a P0807 code. Maybe that may be the source to that.
Where was this stated? I have just looked through waht I thought was the entire saga and missed it.

@AutoRaiders : Please list all of the problems that you are currently having.
 

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Discussion Starter #25
Where was this stated? I have just looked through waht I thought was the entire saga and missed it.

@AutoRaiders : Please list all of the problems that you are currently having.
Thanks JohnWR, it was a separate conversation that took place in the DMs that is too long to type out here. Long story short, there was a code P0807 that was picked up by a scanner but no telling how old it was. The current plan is to fix all of the known Issues, and then see what codes the car throws. It should all be going back together today/tomorrow to get it back up running and driving. i have a Tech2 emulator to be able to plug in and read live data so that should help too.

so far the water pump, temp sensor, thermostat, manifold, new gasket/seals, new bolts/studs, spark plugs, fresh oil change, coolant flush, all non-OEM wiring I came across, Cracked/leaking hoses, AC blower resistor and wiring harness (and I am sure I am leaving other things out) have been replaced. So a lot of work without starting it up and running it.

My questions come up as I go when I see things that don’t look right or I’m not smart enough to figure out on my own.

I wish I knew more about the ignition sequence to get rid of that push start. It looks like the push button has the wires running to the relay in the fuse box and that’s all. My (limited) understanding is that the clutch positioning sensor will let the car start without pushing in the clutch (although I have not tried this yet). So if the clutch positioning sensor goes back in and plugged into the ECM, it should revert back to OEM?
 

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Thanks JohnWR, it was a separate conversation that took place in the DMs that is too long to type out here. ........

I wish I knew more about the ignition sequence to get rid of that push start. It looks like the push button has the wires running to the relay in the fuse box and that’s all. My (limited) understanding is that the clutch positioning sensor will let the car start without pushing in the clutch (although I have not tried this yet). So if the clutch positioning sensor goes back in and plugged into the ECM, it should revert back to OEM?
Hence the reason i discourage using a mix of PM and post for this sort of thing. Pieces of data get left out and make troubleshooting more difficult.

The P0807 is a live code that is caused by the lack of a CPP Sensor. It will certainly be there when you power the car again.

Yes, the hotwired start button will let the starter turn the engine over without the clutch being released.

You need to install a CPP Sensor, then use the Tech2 to calibrate it. At that point you should be able to start the car normally, unless something else has been hacked.
 

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Where was this stated? I have just looked through waht I thought was the entire saga and missed it.
Thanks JohnWR, it was a separate conversation that took place in the DMs that is too long to type out here. Long story short, there was a code P0807 that was picked up by a scanner but no telling how old it was.
Sorry to cause additional confusion. It appears I checked out this car before @AutoRaiders purchased it. In summary the car was not as advertised and I had to walk away empty handed. When I saw the description of all the issues with this car I got a bit of deja vu and later confirmed through our conversation that it is in fact the same car. While conversing I thought I should pass on everything that I discovered about the car while I was there. Some of those issues were quite a few codes. @AutoRaiders is definitely nobler then me in his attempt to restore this car.
 

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Discussion Starter #28
Hence the reason i discourage using a mix of PM and post for this sort of thing. Pieces of data get left out and make troubleshooting more difficult.

The P0807 is a live code that is caused by the lack of a CPP Sensor. It will certainly be there when you power the car again.

Yes, the hotwired start button will let the starter turn the engine over without the clutch being released.

You need to install a CPP Sensor, then use the Tech2 to calibrate it. At that point you should be able to start the car normally, unless something else has been hacked.
I got a little bit of time to work on the car and after looking closer, the stock CPP sensor was there all along and in position, just unplugged. I plugged it back in, does it still need to be calibrated or should it function as normal given that it was the original one? The Tech2 is an emulator that my neighbor is graciously letting me use (and helping with it’s use). IF it needs to be calibrated, will that be able to do it also or does it have to be Tech2 specifically?

In terms of this push putting start, it looks like all it is, is a Hotwire switch. There are 2 wires running to the fuse box referenced towards the beginning of this thread and that’s all I see. It’s not spliced in anywhere else.

in terms of concerns about what else has been wired in, that is a very valid question. So far I have taken the car apart down to bare aluminum and the non-OEM wiring was very evident, they were not trying to conceal anything. So I feel fairly confident that the wiring towards the back of the car, under the dash, and under the hood is good now. The only thing I did not take apart is the upper portion of the dash and instrument cluster.

The known issue that is remaining is the speedo and odometer. Once running and driving again, my plan is to plug in the OBD reader and see what the ECM is reading. please correct me if I am wrong but I think there are 2 outcomes:
1. When driving the reader will not show me my speed (mph). This should mean that it is not getting the reading from the VSS. The fix would be to trace the wires again between the VSS and the ECU for any breaks. If none present, then it has to be the VSS?
2. The reader displays the accurate speed but the speedometer shows 0 mph and the odometer is not counting. The fix has to be between the ECU and the speedometer? Perhaps unplugged? It doesn’t have any after market gauges and looks stock so I don’t think the upper dash has been removed but I could be wrong.

Am I missing any other possible outcomes?
 

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The CPP Sensor should not require calibration if it has been calibrated previously. My question is why it was disconnected, and therefore why the pushbutton was added. It is possible that the sensor had a problem, and the pushbutton was put in to bypass it, but it is also possible that the sensor was unplugged because it was interfering with the pushbutton.

The emulator should be able to do anything that the Tech2 can do, so if it does require calibration you should be OK.

The IP Cluster communicates to the ECM through a data link, and there are not individual wires for the different instruments, so if the tachometer works but the speedometer doesn't. the problem is not in the data link. The speedometer could have a problem within the IP, but that would not explain the odometer failing to increment since it gets its data from the BCM over the same data link that allows you to scroll through the menus.

You are unlikely to see any speed data with the emulator, but it is definitely worth trying.

Something else you can check is to see if there is a 5V supply on the yellow wire at the VSS. That will at least tell you about half of the circuit.
 

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Discussion Starter #30
So everything has been assembled and rebuilt. The car fired up, I Cleared all codes, and went for a ~1 mile drive in the neighborhood. Some new things happened, perhaps they are all related to the codes and once the codes are fixed, everything else should clear?

1. Within seconds of starting the car, I got Service Traction Control; Service ABS; and ESC OFF messages. Followed by engine reduced power. I turned it back off not knowing if it will cause damage. Powered back on and traction control, ESC off, and reduced power remained on.

2. I scanned for new and pending codes. 2 were the same (P0807 & P0502) and 1 was new to me (P2127).
- In regards time clutch position sensor, I plugged the original one back in, disconnected the hot wire switch and the car wouldn’t start. So I don’t know if the switch needs to be calibrated or if it went bad which is what prompted the hot wire start?
-In order to start the car, I wired the switch back in and it started with no problem. Even though ClutchPosition Sensor is plugged in, it’s probably bad and not reading it?
  • as you suspected JohnWR, when I went for a drive the Scanner did not pick up a MPH output, it read 0. I am pretty sure that I drove at least a mile and the odometer didn’t change either. Tach, fuel, and all other sensors worked (coolant temp, etc). So not sure where to go with this P502 sensor besides check the yellow 5v connection and then replace the VSS?
  • P2127 is a new one to me, will have to research this one.
3. all 4 wheels have dashed lines for psi. I took the tool thatchecks reads/checks for TPMS presence and if they are still good and found that 3 sensors are still good and reading data, while 1 of them is dead. I bought an OEM replacement and should be here soon. As for other 3, I need to figure out how the TPMS sensors are reset and relearned. Would lack of TPMS data cause any of the other issues (besides low tire alert on the dash)?

thank you again for the help. This has been an incredible learning journey and I feel like I have gotten to learn the car very well in the last week. 🙂

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Easy one first. The 2008s had a known bug in the TPMS system where a power loss would erase the program. The fix requires a dealer or a paid connection to GM's TIS2WEB with a Tech2 (or your emulator) to reflash the module. Once reflashed the problem will not return. Have you tried re-pairing the sensors? With the Tech2 and the TPMS checker you seem to have it is quick and easy, and only slightly less so with just the checker.

I have nothing to indicate that a TPMS problem will cause anything else.

This won't fix anything and probably won't show you anything either, but the trip odometers register in tenths of a mile.

The Tech2 will let you look at the CPP and TPP sensor inputs. I would do that next.

What shape is the battery in? Your problems seem to go beyond that, but we have seen a lot of weird problems caused by weak batteries and bad battery cables. Bad grounds can also cause problems, so check the grounds on the passenger side frame rail next to the engine and the one on the transmission tunnel next to the hand brake and under the armrest.

For the first time, two of those codes, P0502 and P0807, are not in the manual, or at least i haven't found them.
 

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The P0502 trouble code means that the Engine Control Module (ECM) has detected a different reading of speed between the vehicle speed sensor and the wheel speed sensors. The P0807 code appears in vehicles using manual transmissions and indicates that the powertrain control module (PCM) has found a malfunction in the clutch position sensor circuit. It can appear in automatic vehicles, meaning there is a PCM error. The P2127 code means that the throttle or pedal position sensor switch E has a low input. The pedal position sensor is a sensor found on the gas pedal. ... When the ECU detects a low input from the pedal, it will trigger the Check Engine Light and the code P2127.
 

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Discussion Starter #33 (Edited)
Would these codes also be the reason for the Service Traction Control, ESC OFF, and engine reduced power? While I had the car apart, I visually checked the wheel sensors to make sure there is no physical damage or play. They looked ok. Is there another way to test wheel speed sensors?

unfortunately I do not have a keyfob for the vehicle so don’t know how to reset TPMS sensors besides a scanner tool.

Trip A/B are in decimal points but did not turn either. They are zeroed our.

to check for 5v supply on the yellow wire, are you referring to getting under the car, unplugging the connector from the VSS, turning the car to the ON position (engine off), and measuring with the multimeter?

Reading through other forums, P0502 code referred specifically to the VSS. Once replaced, the speedometer and Odometer worked again. 🤷‍♂️

I checked with battery tester and the battery tested good. It is 1.5 years old. Verified grounds in the locations you mentioned and all are secured.

I have access to an Elite CP9185 scanner tool. It has a Control On-Board Systems function but when I go to use it, it says “Control on-board systems unavailable on this vehicle”. This scanner tool does scan for GM, Chrysler, and Ford. Does that error mean I need to do something with the car, or the scanner simply not compatible with the Sky?
 

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In reverse order:

What you have is not a Tech2 emulator. I did not find a reference to that specific scanner, but if I am reading the coverage description correctly the CP9580A, which appears to be the next generation, will not do what you need. That suggests that what you have will not work either. Most aftermarket scanners are limited to OBD2 and some other core systems, and will not let you look at subsystems that the Tech2 can. Someone else may have better information.

Check the battery and grounds off the list tentatively. There are other, less applicale grounds, and battery testing is not absolute, but you are probably OK.

Assuming the wiring is intact, replacing the VSS is a logical move. The prolem is either with it, the wiring, or the ECM. $86 from Rock Auto.

Yes, you want to check at the VSS to confirm that the ECM is supplying the voltage and that the wiring is getting it there.

I didn't expect them to have changed, but it eliminates the concern about maybe not going a full mile.

You may be out of luck with that one, short of going to a dealer. Many private shops have Tech2s or true emulators, so it might be worth asking around.

The Tech2 will, but you know there is a problem with the VSS, so fix that first, then see what doesn't work. Absent physical damage the wheel speed sensors are pretty bullet proof.
 

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Discussion Starter #35
Thank you sir. I have another neighbor who mentioned that he has an HP Tuner. Again, due to my lack of knowledge and continued learning, I don’t know capabilities of it either? He has a blown Vette with quite a bit of work done to it so I assume that’s why he has it.

In terms of VSS, I got back under the car with a multimeter and tried to see if it would read anything. My multimeter needle wont reach the terminal and the connector pin is very thin. I striped a small wire and pushed it into the pin (without grounding it out on the transmission case) and tried that. I turned the ignition on (engine off) and it read 0. Again though, I may not have had a good connection though. Any other tricks to see if there is power in the yellow wire (short of cutting the yellow wire and then splicing it back in, which I don’t want to do unless I have to)?

then I pulled VSS out all together, and here is what I found. Quite a bit of sludge but sensor intact. With what’s on this sensor, does this warrant a transmission flush?

I traced the wires as far as I could and looks like wiring harness Y’s into 2: one runs along side of the tranny into the engine bay, the other feel like it goes into the center console?This is purely based on feeling with my hand, I can’t see for sure.

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That plug is magnetic. Its doing what it should. Clean that crap off of it and put it back to continue cleaning the fluid. But with that much iron filings on it you may have a problem with the tranny.
(Voltage(E) is potential, Current(I) is electron flow, Power is Voltage times current. To measure the VOLTAGE in a wire without cutting it or accessing either end, push a straight pin thru it and put the meter probe on the pin. Just remember to remove the pin when done.!
 

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Discussion Starter #37
That plug is magnetic. Its doing what it should. Clean that crap off of it and put it back to continue cleaning the fluid. But with that much iron filings on it you may have a problem with the tranny.
(Voltage(E) is potential, Current(I) is electron flow, Power is Voltage times current. To measure the VOLTAGE in a wire without cutting it or accessing either end, push a straight pin thru it and put the meter probe on the pin. Just remember to remove the pin when done.!
Does the key have to be in the ON position or vehicle running? Just want to verify I am taking the right steps in case it is reading 0v.
 

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IDK
 

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Discussion Starter #39 (Edited)
Well, the car was on (engine not running) and I tried the pin approach and it read 0V. So looks like there is no power going to the VSS. 😐

I was going through all of the fuses again with a fine tooth comb, and found Fuse #29 (DLC - Data Link Connector) was mis-placed in the empty slot #31. It sounds pretty important 🤦‍♂️ what does DLC Control/manage? Curious what to look for now that the 15a fuse is in the right spot.

“The data link connector(DLC) is the multi-pin diagnostic connection port for automobiles, trucks, and motorcycles used to interface a scan tool with the control modules of a given vehicle and access on-board diagnostics and live data streams.”

not sure if that’s what limited the function of the scanner tool, but OBDII read the codes and fed the live data to the scanner while driving.
 

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I finally found DTC P0502 in the manual. (It wasn't in the index.)

The VSS is a permanent magnet generator, which is probably why it has attracted the metal filings. As the transmission tailshaft rotates it generates a fluctuating voltage that increases frequency and amplitude as the tailshaft turns faster.

The test procedure is to put the vehicle on a rack, start the engine, engage a gear, and watch for the input on the Tech2. You could probably check it with an oscilloscope, but I have no idea what would be good or bad.

There are some electrical tests you can do with an ohmmeter:

With the VSS connected, unplug connector X2 from the ECM

Check the resistance between terminal 53 (Yellow) and terminal 40 (Purple):
  • More than 1500 Ohms indicates a cut or damaged wire
  • Less than 1300 Ohms indicates a shorted wire
Then check the resistance between:
  • Terminal 53 (Yellow) and Ground. Less than 10 Ohms is a short circuit.
  • Terminal 40 (Purple) and Ground. Less than 10 Ohms is a short circuit.
With X2 connected and the VSS unplugged you should have voltage at the Yellow wire with the ignition on.

I also found P0807. (Also not in the index.)

This code says that the CPP Sensor is not returning any voltage to the ECM. First unplug the CPP Sensor:
  • On the sensor measure resistance between terminal B (Light Green) and terminal A (Orange/Dark Green) as you sweep the sensor through its range. The resistance should vary smoothly.
  • Ignition OFF test for less than 1 Ohm between the Light Green wire and battery negative
  • Ignition ON test for 5 V between the Dark Blue/White wire and ground.
 
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