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2007 Chevrolet impala ls 3.5l v6
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Discussion Starter · #1 ·
Now I know the usual cause is wiring and I have checked and fixed all wiring and connectors that I could see that needed to be addressed even the one behind the power steering pump. But I'm still getting a p0340 and p0650 and p0300 as a result of the cam code im assuming. But I'm stumped so any suggestions are welcome. Please lmk how you fixed this issue. My only other guess is the cam magnet is actually bad because that's the only sensor I havent replaced. Does anyone know the symptoms? My car is a 2007 3.5 v6
 

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P0650 is an MIL lamp circuit malfunction.
P0300 is a generic multiple misfire code.
P0340 is a problem in the Cam Position Sensor wiring.

According to the 2009 Chevrolet Impala service manuals P0340 could be a signal short to ground, signal short to hot, or open sensor signal or ground circuit. It's really common for the CPS wiring to get chewed up on the 3.5L & 3.9L engines.
If you don't have damaged wiring between the CPS and the PCM then you need to test the sensor output.
The 2007 Impala CPS sensor should be a three terminal Delphi GT150 connector keyed to mate with the sensor. You can buy repair connector pigtails to solder and heatshrink in place or re-use the original shell with replacement terminals.
For some reason the original Delphi GT150 connectors tend to get brittle fairly quickly from heat cycles. Metripak 150 connectors would've been a better choice.
 

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Discussion Starter · #3 ·
P0650 is an MIL lamp circuit malfunction.
P0300 is a generic multiple misfire code.
P0340 is a problem in the Cam Position Sensor wiring.

According to the 2009 Chevrolet Impala service manuals P0340 could be a signal short to ground, signal short to hot, or open sensor signal or ground circuit. It's really common for the CPS wiring to get chewed up on the 3.5L & 3.9L engines.
If you don't have damaged wiring between the CPS and the PCM then you need to test the sensor output.
The 2007 Impala CPS sensor should be a three terminal Delphi GT150 connector keyed to mate with the sensor. You can buy repair connector pigtails to solder and heatshrink in place or re-use the original shell with replacement terminals.
For some reason the original Delphi GT150 connectors tend to get brittle fairly quickly from heat cycles. Metripak 150 connectors would've been a better choice.
Thanks for the reply. Like I said I'm aware or the wiring issue behind the pump and I tested the sensor. I get 5.05 volts for the 2 outer wires and I assume the center is the ground
 

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The outer terminals are Ignition sensor supply and 5v signal. The centre is the digital ground.
It's possible you blew out the CPS sensor signal channel if it wasn't fried from the wires shorting. The resistance through the meter won't keep the ignition voltage from frying the 5v signal channel.

I test this stuff with a Power Probe III. It allows you to test power and grounds without injecting errant voltages into the PCM signal circuits. Much safer than a meter or test light.
 

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Discussion Starter · #5 ·
The outer terminals are Ignition sensor supply and 5v signal. The centre is the digital ground.
It's possible you blew out the CPS sensor signal channel if it wasn't fried from the wires shorting. The resistance through the meter won't keep the ignition voltage from frying the 5v signal channel.

I test this stuff with a Power Probe III. It allows you to test power and grounds without injecting errant voltages into the PCM signal circuits. Much safer than a meter or test light.
Is the CPS you're referring to crank or cam? Also I changed the alternator and got a connector that was in good condition from the junkyard and rewired that and put a new sensor and haven't got the code to pop back up before it would come on as soon as I started the car even if I erased it it would pop right back up. I havent seen it come back up and the car is driving better but the speedometer gets a little wonky. While driving I noticed about a 10mph bounce that went away in a couple seconds. The speed sensor is new ac delco so I have no idea on that one and no vss code. Only code that pops up now is p0650 which I dont plan on fixing.
 

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We're talking about P0340 so CPS in this context is Cam Position Sensor.

If the MIL lamp isn't lighting with your initial Key On Engine Off then you have your P0650 culprit. If you don't have to pass Emissions inspection you can likely not worry about that.

As far as the VSS goes. Iron crud in the transmission fluid can screw up the VSS along with the valve body solenoids (TCC solenoid, both shift solenoids, and the Pressure Control solenoid). Dodgy wiring can raise hell with it too. And don't rule out the new VSS sensor. NEW is an acronym for Never Ever Works.

Can you plot or log the VSS signal being received by the PCM with your diagnostic tool?
Do you have an oscilloscope to view the VSS signal directly from the sensor?
 

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Discussion Starter · #8 ·
We're talking about P0340 so CPS in this context is Cam Position Sensor.

If the MIL lamp isn't lighting with your initial Key On Engine Off then you have your P0650 culprit. If you don't have to pass Emissions inspection you can likely not worry about that.

As far as the VSS goes. Iron crud in the transmission fluid can screw up the VSS along with the valve body solenoids (TCC solenoid, both shift solenoids, and the Pressure Control solenoid). Dodgy wiring can raise hell with it too. And don't rule out the new VSS sensor. NEW is an acronym for Never Ever Works.

Can you plot or log the VSS signal being received by the PCM with your diagnostic tool?
Do you have an oscilloscope to view the VSS signal directly from the sensor?
I dont have a way to log it but I did notice on the old one there was some gray sludge on it. I changed the solenoids in the trans a few months ago.
We're talking about P0340 so CPS in this context is Cam Position Sensor.

If the MIL lamp isn't lighting with your initial Key On Engine Off then you have your P0650 culprit. If you don't have to pass Emissions inspection you can likely not worry about that.

As far as the VSS goes. Iron crud in the transmission fluid can screw up the VSS along with the valve body solenoids (TCC solenoid, both shift solenoids, and the Pressure Control solenoid). Dodgy wiring can raise hell with it too. And don't rule out the new VSS sensor. NEW is an acronym for Never Ever Works.

Can you plot or log the VSS signal being received by the PCM with your diagnostic tool?
Do you have an oscilloscope to view the VSS signal directly from the sensor?
I dont have a scope to monitor it but on the old sensor there was some grey sludge. I replaced the solenoids in the transmission a few months ago. Only other thing is my alignment is off but idk if that would cause speed sensor issues.
 

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Did you do the transmission pan magnet replacement TSB when you did the shift solenoids?

It might be worth getting a look at the speed reluctor with a USB borescope or inspection mirror for extra iron. It could also just be a dodgy VSS.

Small handheld FPGA scopes like the DSO Nano and DSO Quad are fairly cheap and easy to find. Not as accurate as a Pico, Rigol, HP, or Tek on frequency and voltage measurement but they let you view a waveform to see if something is not quite right.
 

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Discussion Starter · #10 ·
Did you do the transmission pan magnet replacement TSB when you did the shift solenoids?

It might be worth getting a look at the speed reluctor with a USB borescope or inspection mirror for extra iron. It could also just be a dodgy VSS.

Small handheld FPGA scopes like the DSO Nano and DSO Quad are fairly cheap and easy to find. Not as accurate as a Pico, Rigol, HP, or Tek on frequency and voltage measurement but they let you view a waveform to see if something is not quite right.
I dont think I have a pan magnet. I did the replacement pan with a drain bolt but my old pan didnt have one either so I didnt know they were supposed to.
 

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Discussion Starter · #11 ·
Also new issue I've noticed. Turning hard left the transmission kind of freaks out and feels like it's in neutral until the wheel straightens out. Now that the cars aligned it more tolerable and doesn't shake as much but it does occasionally. No codes and no idea what it is.
 

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Someone removed it. That ain't good.
The 4T65E transmissions have a silent chain that sheds iron filings and they end up on your control solenoids and VSS sensor. Engagement issues with the TCC and Pressure Control solenoids can screw up your torque converter clutch and transmission in short order.
The 4T65E pan magnet TSB outlines installing two magnets in the pan. They're the same magnets that GM used on the Allison 1000 and Saturn spin on transmission fluid filters. I would reccomend adding a Magnefine inline magnet/paper filter to the cooler return line and changing this filter and the fluid in the pan on at least the next four engine oil changes.
 
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Discussion Starter · #13 ·
Someone removed it. That ain't good.
The 4T65E transmissions have a silent chain that sheds iron filings and they end up on your control solenoids and VSS sensor. Engagement issues with the TCC and Pressure Control solenoids can screw up your torque converter clutch and transmission in short order.
The 4T65E pan magnet TSB outlines installing two magnets in the pan. They're the same magnets that GM used on the Allison 1000 and Saturn spin on transmission fluid filters. I would reccomend adding a Magnefine inline magnet/paper filter to the cooler return line and changing this filter and the fluid in the pan on at least the next four engine oil changes.
Maybe that's why it always seems to drive better after a fluid change. I ordered the magnets. They'll be here tomorrow
 

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I would add one of these to the return line from the transmission cooler in the radiator and change it at 500 & again at1,000 miles and then four or five times with the engine oil.
These filters have a metal body now. Even some of the counterfeits are metal.

This guy used one of the old ABS body Magnefine filters in his truck and cut it open after 600 miles in service. The thumbnail shows the iron filings on the magnet.
 

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Discussion Starter · #15 ·
I would add one of these to the return line from the transmission cooler in the radiator and change it at 500 & again at1,000 miles and then four or five times with the engine oil.
These filters have a metal body now. Even some of the counterfeits are metal.

This guy used one of the old ABS body Magnefine filters in his truck and cut it open after 600 miles in service. The thumbnail shows the iron filings on the magnet.
Do you know which line is the return on an 07 3.5?
 

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Do you know which line is the return on an 07 3.5?
The horizontal fitting on the transmission is the return line.
This is the hose layout on the 9C1 9C3 cop/taxi models with the GM factory installed AUX transmission cooler (#13 in the illustration).
Colors denote relative temperatures.
Most of the 8th gen Impalas do not have the AUX cooler. The Blue return on the models without the AUX cooler will exit the radiator where the Green pipe is plumbed on the 9C1/9C3 models.


This is the thread on installing the AUX GM cooler on the models not originally equipped.

And one more thread on the same deal.
 
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Discussion Starter · #17 ·
The horizontal fitting on the transmission is the return line.
This is the hose layout on the 9C1 9C3 cop/taxi models with the GM factory installed AUX transmission cooler (#13 in the illustration).
Colors denote relative temperatures.
Most of the 8th gen Impalas do not have the AUX cooler. The Blue return on the models without the AUX cooler will exit the radiator where the Green pipe is plumbed on the 9C1/9C3 models.


This is the thread on installing the AUX GM cooler on the models not originally equipped.

And one more thread on the same deal.
So I did the fluid change and added the magnets today. The fluid was dark and somewhat sparkly with what I assume is metal from the transmission that wasnt getting picked up because there weren't magnets. I cleaned off the speed sensor. Had some gray stuff that I assume is also metal. I'll add a pic. Trans seems to shift fine. Still does a slight surge and idk why. Still acts like it drops in to neutral on a hard left term and this is a non abs model so theres no harness around the wheel bearings. I'm getting a p0300 so idk if that'll effect shifting. I assume it would. I also think the cat may be clogged a little.
 

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That's a lot of metal for a short time. I'd start saving your yankee bucks for a transmission. If it soldiers on for you you just packed some money away. If it dies you have the bucks to fix it.
 
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