1997 Chevrolet Truck



February, 22, 2009 AT 7:29 PM

Computer problem
1997 Chevy Truck V8 Two Wheel Drive Automatic 170000 miles

Hello there.
I have a 1997 C1500 2wd Pickup in which the check engine light is on. The code reported from my handy dandy OBDII reader is P0430 - Cat Sys Below eff Bank 2.
I have narrowed this to an O2 sensor or the Cat.
Can you give me some direction if I am on the right track or completely derailed.
Thanks for your help


5 Answers



February, 22, 2009 AT 7:39 PM

A code P0340 could mean one or more of the following has happened: a wire or connector in the circuit could be grounded/shorted/broken
the camshaft position sensor may have failed
the PCM may have failed
there exists an open circuit
the crankshaft position sensor may have failed

Possible SolutionsWith a P0340 OBD-II trouble code, diagnosis can be tricky at times. Here are some things to try: Visually inspect all the wiring and connectors in the circuit
Check for continuity in the circuit wiring
Check the operation (voltage) of the camshaft position sensor
Replace the camshaft position sensor as required
Check the crankshaft position circuit as well
Replace circuit wiring and/or connectors as required
Diagnose/replace the PCM as required



February, 23, 2009 AT 5:37 PM

Poster said a PO430 code, not a 340.




February, 23, 2009 AT 6:40 PM

My bad

P0430 OBD-II Trouble Code
Technical DescriptionCatalyst System Efficiency Below Threshold (Bank 2)

What does that mean?Basically this means that the oxygen sensor downstream of the catalytic converter on bank 2 is detecting that the converter is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

SymptomsYou will likely not notice any drivability problems, although there may be symptoms such as a rough/hard idle when cold.

CausesA code P0430 may mean that one or more of the following has happened: The catalytic converter is no longer functioning properly
An oxygen sensor is not reading (functioning) properly
There is an exhaust leak
Possible SolutionsFirst, inspect for exhaust leaks.

Next step is to measure the voltage at the oxygen sensor on Bank 2. In fact, it would be a good idea to test each oxygen O2 sensor while you're at it.

One thing to note is that many vehicle manufacturers offer a longer warranty on emissions-related parts. So if you have a newer car but it's out of it's bumper-to-bumper warranty, there still may be warranty on this type of problem. Many manufacturers give a five year, unlimited mileage warranty on these items. It's worth checking into.



February, 23, 2009 AT 10:23 PM

In testing the sensor. What is the procedure? What am I looking for?



February, 24, 2009 AT 3:11 PM

You need a scantool to view the switching activity of the oxygen sensors. Or use a voltmeter and probe the signal wire to ground -Verify that the sensor voltage fluctuates rapidly between 0.40-0.60 volts.

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