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Category: Chevy
Satisfied Customers: 23681
Experience:  ASE certified tech ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
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2002 chevy blazer: trouble codes..P1683,P0155, P0128, P0135, P0101

Customer Question

I am working on a 2002 chevy blazer, 4.3 engine. It gave me 5 trouble codes to start with, P1683,P0155, P0128, P0135, P0101. I did a complete tune up with plugs, wires, cap and rotor. I erased all the codes. The mass air sensor kept coming on until I replaced it. I do not have any check engine lights on now. Engine performance is very slugish and will not reach 55 mph. fuel pressure is running about 60 psi. checked timing with otc scanner and it is set at 8 degrees and when I turn the distributer clockwise to retard the timing it increases the timing. I feel like it is the computer.
Submitted: 7 years ago.
Category: Chevy
Expert:  AMEDEE replied 7 years ago.



So there are no codes at this time?

Customer: replied 7 years ago.
No codes showing at this time.
Expert:  AMEDEE replied 7 years ago.
Does it run better with the mass air flow sensor disconnected?
Customer: replied 7 years ago.
Have only replaced it with a new one. that was the only way I could keep the P0101 code from coming back. Have not tried it without. It tends to want to surge while you are trying to build speed.
Expert:  AMEDEE replied 7 years ago.

Does fuel pressure hold steady?


Any air or vacuum leaks?

Customer: replied 7 years ago.
No vacume leaks. Fuel pressure held at 55 psi for over 3 hours and while sitting Ideling.
Expert:  AMEDEE replied 7 years ago.

Sounds like plugged exhaust. The easiest way to check for this is to hook up a vacuum gage to any vacuum source from the intake manifold. It should read about 17 to 19 inches of steady vacuum at idle. Upon snapping the throttle quickly to about 3000 rpm and letting off back to idle, you should see the vacuum gage go from steady 18 inches of vacuum to 0, back past 18 inches of vacuum, to about 23 or 24 inches of vacuum back to about 18. If it does not go back past 18 inches to 23 or 24 before returning to 18 something in the exhaust is definitely plugged up.


Or you can always pull the o2 sensors and see if it makes any difference. :)

Customer: replied 7 years ago.
I will give it a try. The vacume looked good from the scanner, but i will try a vacume guage in stead. There was a code P1683 that I could not find the definition of but when I cleared the codes it did not come back.
Expert:  AMEDEE replied 7 years ago.



The powertrain control module (PCM) electrically erasable programmable read only memory (EEPROM) contains data which is essential for operating the engine and the transmission. The PCM continuously tests the integrity of this data.

The ignition switch is in the crank position or in the run position.

The PCM is unable to correctly read the data from the flash memory.


The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.

IMPORTANT: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.

Replace the PCM even if this diagnostic trouble code (DTC) exists only in history

Category: Chevy
Satisfied Customers: 23681
Experience: ASE certified tech ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
AMEDEE and 3 other Chevy Specialists are ready to help you
Customer: replied 7 years ago.
Thank you for your time and help. This is my neighbors vehicle and I was trying to help him, but it sure has burned alot of my time. Thanks.
Expert:  AMEDEE replied 7 years ago.

Thanks for the accept!


Good luck!

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