SO randomly last weekend my car died on me. scanned it and got a P2105 which says the TB forced engine shutdown, then noticed the O2 readings were frozen at 29:1.

Now heres where it gets weird:

The O2 readings usually waited for the sensor to warm up before all this started happening. Now the sensor attempts to read right when the car starts and displays 29:1 with a frozen voltage of 0mv. I checked the fuse labeled EXH its good, replaced with a brand new ac delco sensor and still same stuff. Even the wiring looked good from what i could see so far and i put contact grease in the connector. I'm stuck with a P0130

I need suggestions bc im about to go nuts with this car.

 

O2 sensor circuit malfunction. If you replaced it with a new OEM sensor, then i'd bet there's some wiring problems.

 

I just checked voltage on each pin, they all have voltage to them, is it possible to have a DOA o2 sensor?

 

doa? dead on arrival? lol

possible, but pretty unlikely..


They all have voltage.........? plugged in? or you unplugged it and checked it at each terminal in the connector?

 

That's plugged in, key on at the connector. With the car running, I'm getting a .47v to.48v swinging from the ecu side of the plug, so that's the signal wire reference voltage I'm assuming at ~450mv. And not heating up at all. I'm thinking the sensor is doa, thanks create engine depot

 

Call Tom if you think that, but it is highly, highly unlikely. I just got a new upstream o2 sensor and it works beautifully.

 

sending it back today for warranty. Its either the sensor or the PCM then. If im getting voltage on the heater wire and signal wire that is correct 12V and .45V respectively, and the sensor doesn't even heat up at all, and still reads 0mv in hp tuners, i think its a sensor issue.

 

Got a new sensor, same issue, getting voltage at the plug, wiring looks good back to the ecu, getting no readings, staying at 0mv. I'm stumped...... Still getting p0130 .

 

How the heck am I getting voltage at the ecu side of the plug and nothing back. Even when the car heats up, I should get some kind of reading on the o2 signal wire, I'm getting nothing on the o2 sensor side. Wtf

 

You have a signal wire voltage reading at the ECM but not at the sensor?.

 

all the ecu wires on the plug have voltage, key on, not running, one at 12v, two at 3v, two at around 2v, when running, the signal wire on the ecu side has a .45v reference signal, which is what it should be, seems relevant. Testing for voltage on the O2 sensor side of the plug, i get no voltage at all from any of the wires even when heating up the sensor by holding the throttle at 1500 rpms. In HP tuners it reads 0mv for the front O2 sensor. I'm seriously stumped. I ordered a new ECU, but hell, im not even sure if thats the issue.

Even when i got the brand new sensor right out of the box and just plugged it in and started the car to see if the sensor warmed up at all, i got nothing, it was cold, but still had the 12v at the heater wire on the ECU side of the plug lol.

I don't even think you can check a wideband that way though, from what i've read, you can only check for a voltage reading through software, not the traditional way of heating it up and watching the voltage change like a regular O2 sensor.

Whats also weird, when the car starts up, it goes right into closed loop and tries to read the sensor and immediately throws the code P0130 and then does a forced shutdown P2105, no open loop for warm up.


I am also wondering, why isn;t any of the terminals reading as a ground? Is there supposed to be a ground on one of the ecu pins? All have voltage, and all are showing that they are not grounded as in high resistance.

 

Should be 2 heater wires, signal and voltage(generic 4 wire o2, not sure of Lnf is different with wideband).

Regardless of wideband or not the sensor needs a ground. If you don't have a ground than you found your problem.

See what the new PCM does, may be a internal problem in the ecu. Without a ground it will immediately throw a hard fault code. Have had it happen before, not on a cobalt though.

 

According to the ECU pinout diagram, its 6 wires on the ecu side, 5 wires on the sensor side. All look correct on voltage. It was suggested to try flashing another tune, as i may have a corrupted file, did no good. Except when i went to start the car, i got a series of fast clicks with my dash going nuts and high beams going nuts lol, then cranked and started. There has to be some issue in the ECU, i then got codes for high voltage on the wastegate solenoid.

67 0.5 TN/WH 3111 Heated Oxygen Sensor Low Signal Sensor 1
68 0.35 WH 5279 Heated Oxygen Sensor Pump Current Sensor 1
91 0.35 L-GN 5278 Heated Oxygen Sensor Input Pump Current Sensor 1
92 0.5 PU/WH 3110 Heated Oxygen Sensor High Signal Sensor 1
96 0.5 GY/WH 3113 HO2S Heater Low Control - Sensor 1

 

Can someone please do me a favor and test their ecu connector and see if any of the wires are a ground???? PLEASE PLEASE PLEASE?

 

I can do it for you later tonight. The wife has my car right now. You asked this for the first time my car has been out of the garage in 3 months.

 

Thank you lol.

I ran across a tech bulletin on how to test the wires on the ecu side, all are at the correct voltage except the high signal wire which is the purple with white stripe, its supposed to be at 2.9 volts, mine is at 4.8v, can you test that one also please? The thing says to check for a short to voltage, how the hell do you test for a short to voltage? Its not like testing continuity to a ground im guessing. I even asked my electrical engineer at work and he didn't know lol. But it also says if the circuit tests normal to replace the ECM.

 

If your ground wire has voltage,then it's shorted to voltage which can really only happen internally in the PCM, unless you have the harness rubbing through somewhere like on the upper charge pipe.

I don't have enough experience with wideband 02's but they can't stray too far away from a narrowband, and unless strictly analog, the sensor needs a ground.

I would check the pinout for you but I'm 3 states away from my car at the moment. Everything sounds like a bad driver in the PCM though.

Edit* I tried to look up the wiring diagram for it on Mitchell but Mitchell only has diagrams for the 2.2/2.4 which is stupid. I can't remember my all data password so I can't check that one sorry.

 

The car did go nuts with all kinds of codes and acted like it had a bad ground when this started, P0130, P0131, P0324, P062B, P3000, also ran on 2 cylinders with knock correction pulling out the max amount. I flashed it with the same tune and it started and ran fine but with that p0130 code and 0 voltage reading from the O2. The rear one reads fine at 460mV lol.

I bought a brand new PCM for $130, so couldn't pass up the deal, but if the dealer flashes it and it still doesn't work, I'm getting rid of this car. Too much stuff going wrong all at the same time.

 

The PCM will probably fix it

 

I'll still wait to see if he finds a ground, the gray/white wire on the ecu plug should be according to wideband wiring, but its showing a voltage signal.
All wiring is verified back to the ecu to be good, no resistance between the o2 plug and ecu harness pins.

And if hes really really nice, if he could do this test for voltage for me?:


I got high voltage (3.4V) on the first one to be tested.








67 0.5 TN/WH 3111 Heated Oxygen Sensor Low Signal Sensor 1
68 0.35 WH 5279 Heated Oxygen Sensor Output Pump Current Sensor 1
91 0.35 L-GN 5278 Heated Oxygen Sensor Input Pump Current Sensor 1
92 0.5 PU/WH 3110 Heated Oxygen Sensor High Signal Sensor 1
96 0.5 GY/WH 3113 HO2S Heater Low Control - Sensor 1


Ignition OFF, disconnect the HO2S 1.
Ignition ON, test for 2.9 volts between the HO2S 1 High Signal circuit terminal 6 and ground.

¤ If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the ECM.
¤ If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM.

Ignition ON, test for 2.5 volts between the HO2S 1 Low Signal circuit terminal 2 and ground.

¤ If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the ECM.
¤ If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM.

Ignition ON, test for 2.8 volts between the HO2S 1 Output Pump Current circuit terminal 1 and ground.

¤ If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the ECM.
¤ If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM.

Ignition ON, test for 2.8 volts between the HO2S 1 Input Pump Current circuit terminal 5 and ground.

¤ If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the ECM.
¤ If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM.

Ignition OFF, disconnect the ECM connector X1.
Ignition OFF, test for infinite ohms between each HO2S 1 circuit terminal and all other HO2S 1 circuit terminals.

¤ If less than the specified value, repair as necessary.

If the ECM and all circuits test normal, replace the HO2S 1.

 

Sorry, 08. Forgot to mention my wife wasn't going to be home with my car until late.

Reading your latest post, I realize now that I don't think I did this how you wanted me to, but I disconnected my battery, disconnected both ECU plugs, and probed all sockets.

The passenger side socket had ground on the following sockets: 17 and 18.

The driver's side socket had ground on the following sockets: 1, 2, 4, 22, and 52.

As far as how you are reading voltage with the battery connected, you would have to tell me your method. I couldn't back-probe the ECU connectors because the wires head down into a 90 degree turn when entering the connectors. I'm a nice guy, but I'm not poking holes in my wires.

If there is another way you want me to do this, let me know and I'll try to get it done tomorrow.

 

Let me know what you come up with by doing the unplug the front o2 sensor and probe the harness side plug that plugs into the o2 sensor socket, not the ECU plugs by the coolant overflow, just the O2 sensor plug. Then turn key on, and probe the purple/white striped wire, if its 2.9v or not, mine is high at 3.4V so that may be the problem. Also i dont think there is a ground wire on the plug for the O2, from my understanding it grounds itself via the exhaust pipe that its screwed in to, but im curious if you find a ground wire on the O2 plug.


And thank you again, i'm glad some people are nice enough to help me out with this


Honestly after searching the entire interweb for the last couple days, the heater wires are all correct except the one that has high voltage to it (purple/white stripe wire), and the circuit tests fine, no short to ground or to voltage, so it says replace ecu. I hope that will solve this, bc the dealer is going to charge me $96 just to flash it.......

So try this for me please.

STEP 1) Ignition OFF, disconnect the HO2S 1.

STEP 2) Ignition ON, test for 2.9 volts between the HO2S 1 High Signal circuit terminal 6 and ground.
PURPLE/WHITE 3110 Heated Oxygen Sensor High Signal Sensor 1

¤ If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the ECM.
¤ If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM.

STEP 3) Ignition ON, test for 2.5 volts between the HO2S 1 Low Signal circuit terminal 2 and ground.
TAN/WHITE 3111 Heated Oxygen Sensor Low Signal Sensor 1

¤ If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the ECM.
¤ If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM.

STEP 4) Ignition ON, test for 2.8 volts between the HO2S 1 Output Pump Current circuit terminal 1 and ground.
WHITE 5279 Heated Oxygen Sensor Output Pump Current Sensor 1

¤ If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the ECM.
¤ If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM.

STEP 5) Ignition ON, test for 2.8 volts between the HO2S 1 Input Pump Current circuit terminal 5 and ground.
LIGHT GREEN 5278 Heated Oxygen Sensor Input Pump Current Sensor 1

¤ If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the ECM.
¤ If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM.

Also, please let me know what voltage the GRAY/WHITE 3113 HO2S Heater Low Control - Sensor 1 has

 

Ok, so here is the results. I'm not sure how much they will help since my potentials were lower than the suggested.

Step 2) 2.68V
Step 3) 2.51V
Step 4) 1.96V
Step 5) 1.96V

Hang on, I just saw your request for the 3113. Lemme go check that.

 

Gray/White Voltage is 4.88V. I have no grounds. Every terminal has potential.

btw, I assume a short to voltage is implying zero current.

08, you haven't messed with the frame-ground connection for any reason, correct?

 

yeah your readings are much different than mine i wonder why, i just got a new battery or maybe your battery is old IDK, mine all match what it specifies except that first one was high, im assuming thats a problem. I have the same 4.8V to that wire so thats good, thats aone of two heater wires, the other has 12V, I was under the assumption that a short to voltage was just no resistance to positive power? I literally can't find on google how to test short to voltage.

And good i figured it just grounds itself on the exhaust, and i have no resistance to ground on the housing either so the ground should be good, where is that frame ground located anyways?

Confusing me is is why it doesn't even heat up, its getting the 12v and 4.8v on the heater wires that yours does. Whats the possibility of getting two bad O2 sensor from CED in a row lol.