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John, ASE Master Technician
Category: Chevy
Satisfied Customers: 614
Experience:  ASE Certified Master Technician, ASE Certified Service Consultant, 22 years professional experience
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Getting trouble codes P0449, P0014, P2135, P2138, P0641 also

Customer Question

getting trouble codes P0449, P0014, P2135, P2138, P0641 also getting C0040, C0455, C0131, C0244, and U1064, U1016. any advise ?
JA: Just to clarify, what's the exact code? And have you tried to reset it?
Customer: Just reset , reading codes with a innova 3020b reader,
JA: What is the model/year of your Chevy?
Customer: 2003 Trailblazer inline 6
JA: Are you fixing your Trailblazer yourself? What have you tried so far?
Customer: trying to, nothing so far just getting info of codes,
JA: Anything else you want the mechanic to know before I connect you?
Customer: car seems to go into a reduced power mode when it rains,
Submitted: 10 months ago.
Category: Chevy
Expert:  John replied 10 months ago.

Hello, my name is John.

You have a lot of codes here and for multiple systems. My advice would be to narrow down what is you would like to fix. I can help you with that. I can provide you with descriptions for all these codes if you would like. Is your goal to keep your check engine light off? Or to fix the problem of the 'Reduced Power' message when it rains?

Please get back to me on that and in the mean time I will follow this post with a new post of code descriptions.


Expert:  John replied 10 months ago.

P0449 - Evap vent solenoid circuit.

P0014 - Variable camshaft timing.

P2135 - Throttle bodyperformance.

P2138 - Accelerator pedal position sensor.

P0641 - 5 volt refrence circuit.

C0040 - ABS brake circuit.

C0455 - ABS brake circuit.

C0131 - ABS brake circuit.

C0244 - EBCM control valve.

U1064 - Serial Data Class 2 Communication malfunction.

U1016 - Serial Data Class 2 Communication malfunction.

Codes P2135, P2138 and P0641 may all be related and can cause the Reduced Power message.

Code P0014 could also cause a Reduced Power message but for a different reason.

I would recommend focusing on these for starters. They are more likely to resolve whatever issue you intend to fix and fixing these may fix some of the other codes. The 'C' codes are all ABS brake related, we can address those seperately if you would like. That would require a new question post.

Expert:  John replied 10 months ago.

Still need help? I have not heard back from you.

Expert:  John replied 10 months ago.

I saw that you opened another question requesting more information on the codes. That question was locked by Customer Service. If you just respond to this feed then I will see your responses.

Expert:  John replied 10 months ago.

The first thing I would do with those codes to address the Reduced Power message is to clean the throttle body. It can get gummed up and stick causing the P2135, P2138 and P0641.

If that does not fix it then there is a possibility that another component, a common one in the cooling fan, is interfering with the 5 volt ref circuit for the throttle body.

Let me know how things go with the cleaning first and we can dig into the second part of that if needed.

ANother code of concern is the P0014 code. The first thing to look at there is engine oil level and condition. If the oil is dirty or low that can cause the phaser to stick or the tensioner to stick and cause a timing issue. However, I would think this would happen in all conditions, not just rain. If there is any concern oabout the engine oil I would just change it and replace the filter with an AC Delco filter.

Start with that and let me know.

Customer: replied 10 months ago.
we clean the throttle body each time this happens, (this has happened off and on for the last two years in wet conditions) it doesn't clear it immediately, I cleared the codes when I first sent this question, as of today, the only code that has come back is P0449, in dry conditions the car is running fine. ( going to work know will look for response)
Expert:  John replied 10 months ago.

Check for chafed wiring at the following components:
Throttle Position Sensor (TPS) 1, Accelerator Pedal Position (APP) sensor 2, engine cooling fan speed sensor, AC pressure sensor, Fuel Tank Pressure (FTP) Sensor, oil pressure sensor.

If no harness problem found, disconnect each component one at a time and see if the problem is resolved.

Tech Tips:The P0641 code is set when there is a problem with the 5 volt reference circuits for the devices listed above.

Expert:  John replied 10 months ago.

The P0449 code is for Evaporative Emissions. Possibly the EVAP Vent Solenoid has failed or is sticky. Or there is a leak in the system. This should not cause the poor running problem.