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Pete
Pete, Auto Service Technician
Category: Chevy
Satisfied Customers: 24668
Experience:  14 years GM dealer Technician.
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I have a 2009 Chevy Malibu Hybrid. Car died out at highway

Customer Question

I have a 2009 Chevy Malibu Hybrid. Car died out at highway speed. Restarted but would only go 5 mph. No codes. Finally got it towed home and it threw a fuel position actuator code. Replaced, code is gone but car will start run for about 2 seconds and shut down. No codes at all, security light is NOT on but have tried anti theft reset anyway. Fuel pressure is spot on. Need suggestions as to what next?
Submitted: 1 month ago.
Category: Chevy
Customer: replied 1 month ago.
I unplugged the MAF and I can get car to stay running (idle isn't bad) but the minute you put down the excelerator its chokes out
Expert:  Pete replied 29 days ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

Inspect for any damaged or shorted wiring leading to the MAF sensor and fuel components that may be causing this fault here.I have also seen issues with the engine coolant temp sensor sending incorrect engine coolant temp readings that will also cause this here.If this is or was checked and found to be o.k. let me know so we can continue.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 28 days ago.
Ok this thing has me baffled....so come to find out that the catalytic converters were both trashed. Which is a bit concerning giving I put brand new ones on not more that 18 months ago. So originally I was getting TPS code so I do have a brand new TB unit on the car, a brand new MAF as well.It runs good except now I am getting high idle condition and a P0223 code. And the transmission acts like its "confused" when called to down shift. (I suspect the high idle is causing this? I didn't read the actual RPM from my scanner, but looking at the gauge its about 200-300 what it should be. I think warm in park idle is about 600ish and it settles down to(###) ###-####I have to doubt the actual pedal sensor but maybe I guess. Thoughts?
Customer: replied 28 days ago.
One additional note. I did try the idle reset and idle learn. As well maybe they are different for my car. First was key on for 5 sec, off for 10, wait 60 secs. start car. Second was start car (warm), put in drive let idle 5 min, then in park 5 min shut off for 1 min, test drive
Customer: replied 28 days ago.
I mean I suppose its possible I got a bad unit but how likely is that?
Expert:  Pete replied 28 days ago.

A faulty TPS sensor or wiring faults to the TPS or even an internal engine ecu fault will cause the code as well as the high idle and transmission shifting issues for sure here.I would follow the diagnostics for the code and see what it leads to as the fault here.This can also prematurely cause the catalytic converters to fail.Other components that can cause the catalytic converters to fail is to much fuel into the engine due to injector issues.

DTC P0223
- Throttle Position (TP) Sensor 2 Circuit High Voltage

Circuit/System Description

The throttle actuator control (TAC) system uses 2 throttle position (TP) sensors to monitor the throttle position. The TP sensors 1 and 2 are located within the throttle body assembly. Each sensor has the following circuits:

* A 5-volt reference circuit
* A low reference circuit
* A signal circuit

Two processors are also used to monitor the TAC system data. Both processors are located within the engine control module (ECM). Each signal circuit provides both processors with a signal voltage proportional to throttle plate movement. Both processors monitor each other's data to verify that the indicated TP calculation is correct.

Conditions for Running the DTC

P0120, P0122, P0123, P0220, P0222, P0223
* The system voltage is more than 5.23 volts.
* The ignition is in the Unlock/Accessory or Run position.
* DTC P0641 is not set.
* DTCs P0120, P0122, P0123, P0220, P0222, P0223 run continuously when the above conditions are met.

P2135
* The system voltage is more than 5.23 volts.
* The ignition is in the Unlock/Accessory or Run position.
* DTCs P0120, P0220, P0641, P0651 are not set.
* DTC P2135 runs continuously when the above conditions are met.

Conditions for Setting the DTC

P0120

TP sensor 1 voltage is less than 0.27 volt or more than 4.67 volts for more than 0.5 second.

P0122

The ECM detects that the TP sensor 1 voltage is less than 0.27 volt for more than 0.4 second.

P0123

The ECM detects that the TP sensor 1 voltage is more than 4.67 volts for more than 0.4 second.

P0220

The TP sensor 2 voltage is less than 0.31 volt or more than 4.7 volts for more than 0.5 second.

P0222

The ECM detects that the TP sensor 2 voltage is less than 0.31 volt for more than 0.4 second.

P0223

The ECM detects that the TP sensor 2 voltage is more than 4.7 volts for more than 0.4 second.

P2135

The difference between the TP sensor 1 and TP sensor 2 exceeds a predetermined value for more than 2 seconds.

Action Taken When the DTC Sets

* DTC P0120, P0122, P0123, P0220, P0222, P0223, and P2135 are Type A DTCs.
* The control module commands the TAC system to operate in the Reduced Engine Power mode.
* A message center or an indicator displays Reduced Engine Power.
* Under certain conditions, the control module commands the engine OFF.

Conditions for Clearing the MIL/DTC

DTC P0120, P0122, P0123, P0220, P0222, P0223, and P2135 are Type A DTCs.

Circuit/System Verification

1. Ignition ON, observe the TP sensor 1 voltage parameter. The reading should be between 0.27-4.67 volts and change with accelerator pedal input.
2. Ignition ON, observe the TP sensor 2 voltage parameter. The reading should be between 0.31-4.7 volts and change with accelerator pedal input.
3. Observe the TP sensor 1 and 2 parameter. The scan tool should indicate Agree.
4. Clear the DTCs with the scan tool. Operate the vehicle within the Conditions for Running the DTC, or within the conditions that you observed from the Freeze Frame/Failure Records.
5. Verify that DTC P0120 or P0220 are not the only throttle position DTCs set.

◊If DTC P0120 or P0220 are the only DTCs set, replace the control module.

6. Verify that DTCs P0641 or P0651 are not set.

◊If DTC P0641 or P0651 is set, refer to DTC P0641 or P0651

7. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the throttle body. Allow sufficient time for the ECM to completely power down.
2. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal C and ground.

◊If greater than 5 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal E and ground.

◊If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
◊If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.

4. Verify the scan tool TP sensor 1 voltage is less than 0.1 volt.

◊If greater than 0.1 volt, test the signal circuit terminal D for a short to voltage. If the circuit tests normal, replace the ECM.

5. Verify the scan tool TP sensor 2 voltage is greater than 4.8 volts.

◊If less than 4.8 volts, test the signal circuit terminal F for a short to ground. If the circuit tests normal, replace the ECM.

6. Install a 3A fused jumper wire between the signal circuit terminal D and the 5-volt reference circuit terminal E of the TP sensor 1. Verify the TP sensor 1 voltage is greater than 4.8 volts.

◊If less than 4.8 volts, test the TP sensor 1 signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

7. Install a test lamp between the signal circuit terminal F of the TP sensor 2 and ground. The test lamp should not illuminate.

◊If the test lamp illuminates, test the TP sensor 2 signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

8. Install a 3A fused jumper wire between the signal circuit terminal F and the low reference circuit terminal C of the TP sensor 2. Verify that the TP sensor 2 voltage is less than 0.1 volt.

◊If greater than 0.1 volt, test the TP sensor 2 signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

9. Ignition OFF, disconnect the harness connector at the ECM.
10. Test for less than 5 ohms on all TP sensor circuits between the following terminals:

* The 5-volt reference circuit terminal E to the corresponding ECM terminal
* The signal circuit terminal F to the corresponding ECM terminal
* The signal circuit terminal D to the corresponding ECM terminal

◊If greater than 5 ohms, repair the affected circuit.

11. Test for infinite resistance between TP sensor 1 signal circuit terminal D and TP sensor 2 signal circuit terminal F.

◊If less than infinite resistance, repair the short between TP sensor 1 signal circuit and TP sensor 2 signal circuit.

12. If all circuits test normal, replace the throttle body.

Here is the throttle learn procedure.

Throttle Learn

With Scan Tool-Reset
1. Ignition ON, engine OFF. With a scan tool, perform the Idle Learn Reset in Module Setup.
2. Start the engine, monitor the TB Idle Airflow Compensation parameter. The TB Idle Airflow Compensation parameter value should equal 0 percent and the engine should be idling at a normal idle speed.

◊If the engine is not idling normally, proceed with the Learn portion of the diagnostic.

3. Clear the DTCs and return to the diagnostic that referred you here.

Important: Do NOT perform the Without Scan Tool-Learn procedure if DTCs are set.

Without Scan Tool-Learn

1. The engine speed is between 450-4,000 RPM.
2. The manifold absolute pressure (MAP) is greater than 5 kPa.
3. The mass air flow (MAF) is greater than 2 g/s.
4. The ignition 1 voltage is greater than 10 volts.
5. Start and idle the engine in Park for 3 minutes.
6. With a scan tool, monitor desired and actual RPM.
7. The ECM will start to learn the new idle cells and Desired RPM should start to decrease.
8. Ignition OFF for 60 seconds.
9. Start and idle the engine in Park for 3 minutes.

Important: During the drive cycle the check engine light may come on with idle speed DTCs. If idle speed codes are set, clear codes so the ECM can continue to learn.

10. After the 3 minute run time the engine should be idling normal.

◊If the engine idle speed has not been learned the vehicle will need to be driven at speeds above 70 km/h (44 mph) with several decelerations and extended idles.

11. After the drive cycle, the engine should be idling normally.

◊If the engine idle speed has not been learned, turn OFF the ignition for 60 seconds and repeat step 6.

12. Once the engine speed has returned to normal, clear DTCs

It is possible you had received a bad unit but is usually unlikely unless it was used.

Let me know if you need anything else and feel free to rate my help here as this is how I receive credit for my time.Your 5 star rating is appreciated

Thanks Pete

Customer: replied 28 days ago.
Ok I tried the learn method you outlined above, it started at about 1093 RPM dropped to about 863 then during the 3 minute run back up to about 960. I can try the drive and learn method, any other things for me to try at this point?
Expert:  Pete replied 28 days ago.

If the learn does not correct the issue here then you will most likely have to follow the diagnostics above to pinpoint the cause of the fault then repair it from there.

Thanks Pete

Customer: replied 28 days ago.
When you say drive above 44 with accelerations and extended idles, can you explain the idle portion? You mean go drive for 10 min above 44 and then park and idle or?
Expert:  Pete replied 28 days ago.

This is saying to drive at 44 or higher with several decelerations (slow downs) and idling.So basically drive up to 44 or more then slow down to idle at a stop and let idle for a minute then repeat over and over to see if it learns in.If it doesnt learn in after about 3 times of doing this then there is an issue that needs diagnosed.

Thanks Pete

Customer: replied 28 days ago.
Is there any chance it could be too much air flow and not enough back pressure through the exhaust? IE: waiting for new cats to come, the originals are empty shells, or can the computer account for that?
Expert:  Pete replied 28 days ago.

If the cats are empty shells this will cause some running issues and this can definitely cause a fault like this here.I would focus on replacing the cats then do the idle learn above and see if this resolves the issue here.

Thanks Pete

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