Went to Autozone, here is the verdict.....

[98_birdman]

-P0122(TPS Circuit Low Voltage)
-P0154(HO2S Circuit Insufficent Activity Bank 2 Sensor 1)
-P0300(Engine misfire detected)
-P0420(TWC System Low Efficiency)
-P0507(Idle Control System High RPM)

Anyone want to help me out in decrypting these codes and let me know exactly what I need to do? Gonna go down now and check the coils and see if I'm getting a spark. My backfiring disappeared but the misfire is even worse now. Any help is appreciated.

[Coriya71]

DTC P0122 Throttle Position (TP) Sensor Circuit Low Voltage

Circuit Description
The Throttle Position (TP) sensor circuit provides a voltage signal that changes relative to throttle blade angle. The signal voltage will vary from below 1 volt at closed throttle to about 4 volts at Wide Open Throttle (WOT). The TP signal is one of the most important inputs used by the PCM for fuel control and most of the PCM-controlled outputs. DTC P0122 will set when the PCM detects an excessively low signal voltage on the throttle position sensor signal circuit.

Conditions for Setting the DTC
No TP sensor, or MAP sensor DTCs are set.
The ignition is ON.
TP sensor signal voltage is less than 0.1 volt.
The above conditions are present for at least 1 second.
Action Taken When the DTC Sets
The PCM will illuminate the MIL during the first trip in which the diagnostic test has been run and failed.
The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.
Conditions for Clearing the MIL/DTC
The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
The DTC can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed.
Diagnostic Aids
Check for the following conditions:

Poor connection at the PCM - Inspect harness connectors for the following conditions:
Backed out terminals.
Improper mating.
Broken locks.
Improperly formed or damaged terminals.
Poor terminal to wire connection.
Damaged harness - Inspect the wiring harness for damage. If the harness appears to be OK, observe the throttle position display on the scan tool while moving connectors and wiring harnesses related to the TP sensor. A change in the display will indicate the location of the fault.

DTC P0154 HO2S Circuit Insufficient Activity Bank 2 Sensor 1

Circuit Description
The PCM supplies a bias voltage of about 450 mV between the HO2S signal and low circuits. When measured with a 10 megohm digital voltmeter, this may display as low as 320 mV. The oxygen sensor varies the voltage within a range of about 1000 mV when the exhaust is rich, down through about 10 mV when exhaust is lean. The PCM constantly monitors the HO2S signal during closed loop operation and compensates for a rich or lean condition by decreasing or increasing injector pulse width as necessary. If the Bank 2 HO2S 1 voltage remains at or near the 450 mV bias for an extended period of time, DTC P0154 will be set, indicating an open sensor signal or sensor low circuit.

Conditions for Setting the DTC
No TP sensor, EVAP system, EGR Pintle, misfire, IAT sensor, MAP sensor, fuel trim, fuel injector circuit, ECT sensor, or MAF sensor DTCs are set.
System voltage is greater than 9 volts.
The following engine run time requirements are met:
Manual Transaxle - 4 minutes.
Automatic Transaxle - 3 minutes.
Bank 2 HO2S 1 signal voltage remains between 400 mV and 500 mV for longer than 2.5 minutes.
Action Taken When the DTC Sets
The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic test has been run and failed.
The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.
Conditions for Clearing the MIL/DTC
The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
The DTC can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed.
Diagnostic Aids
Check for the following conditions:

Poor connection at the PCM - Inspect harness connectors for the following conditions:
Backed out terminals.
Improper mating.
Broken locks.
Improperly formed or damaged terminals.
Poor terminal to wire connection.
Damaged harness - Inspect the wiring harness for damage.
Faulty HO2S heater or heater circuit - With the ignition ON the HO2S voltage displayed on a scan tool should gradually drop to below 300 mV or rise to above 600 mV. If not, disconnect the HO2S and connect a J 34142-B test lamp between the HO2S ignition feed and heater ground circuits. If the J 34142-B test lamp does not light, repair the open ignition feed or sensor ground circuit as necessary. Refer to Heated Oxygen Sensor (HO2S) Replacement . If the J 34142-B test lamp lights and the HO2S signal and low circuits are OK, replace the HO2S. Refer to Heated Oxygen Sensor (HO2S) Replacement
Intermittent test - With the ignition ON, monitor the HO2S signal voltage while moving the wiring harness and related connectors. If the fault is induced, the HO2S signal voltage will change. This may help isolate the location of the malfunction.

DTC P0300 Engine Misfire Detected
Circuit Description
The PCM has the ability to detect a misfire by monitoring the 3X reference and camshaft position input signals from the Ignition Control Module. The PCM monitors crankshaft speed variations (reference period differences) to determine if a misfire is occurring. If 2% or more of all cylinder firing events are misfires, emission levels may exceed mandated standards. The PCM determines misfire level based on the number of misfire events monitored during a 200 engine revolution test sample. The PCM continuously tracks 16 consecutive 200 revolution test samples. If 11 or more misfires are detected during any 10 of the 16 samples, DTC P0300 will set. If the misfire is large enough to cause possible three-way catalytic converter damage, DTC P0300 may set during the first 200 revolution sample in which the misfire was detected. In the case of a catalyst damaging misfire, the MIL will flash to alert the vehicle operator of the potential of catalyst damage.

Conditions for Setting the DTC
No TP sensor, MAP sensor, ECT sensor, CKP sensor, CMP sensor, VSS, or MAF sensor DTCs are set.
Engine speed between 550 and 5800 RPM.
System voltage between 9 and 16 volts.
The ECT sensor indicates a temperature between -6°C (21°F) and 120°C (248°F).
Throttle angle is steady.
The PCM is detecting a crankshaft RPM variation indicating a misfire sufficient to cause three-way catalytic converter damage or emissions levels that exceed the mandated standard.
Action Taken When the DTC Sets
If the misfire level is non-catalyst damaging, the PCM will illuminate the MIL during the second key cycle in which the DTC sets.
If the misfire is severe enough to cause possible catalyst damage, the PCM will immediately flash the MIL while the misfire remains at catalyst damaging levels.
The PCM will disable TCC operation.
The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.
Conditions for Clearing the MIL/DTC
The PCM will turn the MIL OFF on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
A history DTC P0300 will clear after 40 consecutive warm-up cycles have occurred without a fault.
DTC P0300 can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed.
Diagnostic Aids
The scan tool provides information that can be useful in identifying the misfiring cylinder. If the DTC P0300 is currently stored as DTC status Failed Since Code Clear, the misfire history counters (Misfire History Cyl #1 - #6) will still contain a value that represents the level of misfire detected on each cylinder. The scan tool displayed misfire counter values (Misfire History Cyl. #1 through #6) can be useful in determining whether the misfire affects a single cylinder, a cylinder pair (cylinders that share an ignition coil - 1/4, 2/5, 3/6), or is random. If the largest amount of activity is isolated to a cylinder pair, check for the following conditions:

Secondary Ignition Wires. Check the secondary wires associated with the affected cylinder pair for disconnected ignition wires or for excessive resistance. The wires should measure less than 30,000 ohms (30K ohms).
Damaged Or Malfunctioning Ignition Coil. Check for cracks, carbon tracking or other damage. Also check coil secondary resistance. Secondary resistance should be between 5000 ohms and 8000 ohms (5K ohms and 8K ohms).
Substitute a Known Good Coil. Switch ignition coils and retest. If the misfire follows the coil, replace the ignition coil.
If the misfire is random, check for the following conditions:

Crankshaft Position System Variation. Refer to CKP System Variation Learn Procedure . The crankshaft position system variation compensating values are stored in the PCM non-volatile memory after a learn procedure has been performed. If the actual crankshaft position variation is not within the crankshaft position system variation compensating values stored in the PCM, DTC P0300 may set. The crankshaft position system variation learn procedure is required when any of the following service procedures have been performed:
PCM replacement or reprogramming.
Engine replacement.
Crankshaft replacement.
Crankshaft balancer replacement.
Crankshaft position sensor replacement.
Any engine repair(s) which disturbs crankshaft/harmonic balancer to crankshaft position sensor relationship.
System Grounds. Ensure all connections are clean and properly tightened.
Mass Air Flow sensor. A Mass Air Flow (MAF) sensor output that causes the PCM to sense a lower than normal air flow will cause a lean condition. Try operating the vehicle within the fail records conditions with the MAF sensor disconnected. If the lean or misfiring condition is not present with the MAF sensor disconnected, replace the MAF sensor.
Loss of EBCM/EBTCM Serial Data. If the PCM stops receiving data from the EBCM/EBTCM, DTC P0300 can set due to a loss of rough road data. Check for stored ABS/TCS DTCs, especially DTCs related to a serial data malfunction. Refer to A Diagnostic System Check .
Air Induction System. Vacuum leaks that cause intake air to bypass the MAF sensor will cause a lean condition. Check for disconnected or damaged vacuum hoses, incorrectly installed or malfunctioning crankcase ventilation valve, or for vacuum leaks at the throttle body, EGR valve, and intake manifold mounting surfaces.
Fuel Pressure. Perform a fuel system pressure test. A malfunctioning fuel pump, plugged filter, or malfunctioning fuel system pressure regulator will contribute to a lean condition. Refer to Fuel System Pressure Test .
Fuel injector(s) Refer to Fuel Injector Coil Test - Engine Coolant Temperature (ECT) Between 10-35 Degrees C (50-95 Degrees F) . Refer to Fuel Injector Coil Test - Engine Coolant Temperature (ECT) Outside 10-35 Degrees C (50-95 Degrees F) .
Contaminated Fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
EGR System. Check for leaking valve, adapter, or feed pipes which will contribute to a lean condition or excessive EGR flow.
Extended Idle. Excessive open loop operation caused by extended idling or short trip driving may leave deposits on the heated oxygen sensors. The deposits cause oxygen sensors to respond slowly to exhaust oxygen content, affecting fuel control and causing a misfire to be indicated at idle. This condition is not permanent. To determine if this condition is causing the DTC P0300 to be set, review the freeze frame and fail records data for DTC P0300. If the DTC P0300 occurs at high engine speeds, the condition described above did not cause the DTC P0300 to set. If the DTC P0300 occurs at idle or very low engine speeds and at engine coolant temperatures less than 80°C (176°F), the condition described above is very likely the cause of the DTC P0300 being set. The deposits on the heated oxygen sensors can be eliminated by operating the vehicle fully warm at mass air flows above 15 gm/s.

Important
If the level of misfire was sufficient to cause possible catalyst damage (if the MIL was flashing), ensure that the DTC P0420 test is completed and passed after verifying the misfire repair.

DTC P0420 Catalyst System Low Efficiency
Circuit Description
To control emissions of Hydrocarbons (HC), Carbon Monoxide (CO), and Oxides of Nitrogen (NOx), a three-way catalytic converter is used. The catalyst within the converter promotes a chemical reaction which oxidizes the HC and CO present in the exhaust gas, converting them into harmless water vapor and carbon dioxide. The catalyst also reduces NOx, converting it to nitrogen. The converter also has the ability to store excess oxygen and release the stored oxygen to promote these reactions. This oxygen storage capacity (OSC) is a measurement of the catalyst's ability to control emissions. The PCM monitors this process using a heated oxygen sensor (HO2S) located in the exhaust stream past the three-way converter. When the catalyst is functioning properly, the HO2S 2 is slow to respond to a large change in the HO2S1 signal. When the HO2S 2 responds quickly to a large change in the HO2S 1 signal, the OSC and efficiency of the catalyst is considered to be bad and the MIL will be illuminated if subsequent tests also indicate a failure.

Conditions for Running the DTC
Meet conditions for engine warm up. Use the scan tool catalyst data list in order to verify the following.
No VSS sensor, Tp sensor, EVAP, HO2S sensor, misfire, IAT sensor, MAP sensor, IAC sensor, Fuel trim, EGR, ECT sensor, MAF sensor, or CKP sensor DTC's set.
Engine has been running longer than 10 minutes.
Engine coolant temperature (ECT) is above 76°C (168°F).
Baro is above 75 kPa.
Vehicle is in Closed Loop.
Intake air temperature (IAT) is above °-29C (-20 F) and less than 100°C (212°F).
Warm up the catalyst.
Fully open hood.
Transmission is in park (automatic) or neutral (manual).
Set the parking brake.
Engine speed is greater than 1500 RPM for 1 minute.
Return to Idle.
Test the catalyst.
Transmission is in drive (automatic) or neutral (manual).
With in 5-20 seconds the air fuel ratio will go lean above 15.3 for up to 7 seconds, then it may go rich below 14.1 for up to 7 seconds.
Using the scan tool check and see if DTC P0420 has passed or failed this ignition cycle
Conditions for Setting the DTC
The PCM determines that the catalyst's oxygen storage capacity is below a threshold considered acceptable.

Action Taken When the DTC Sets
The PCM will illuminate the MIL during the first trip in which the diagnostic test has been run and failed.
The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.
Conditions for Clearing the MIL/DTC
The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
The DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.
Diagnostic Aids
Check for the following conditions:

The PCM will not enable the catalyst test until following conditions are met:
Engine speed is plus or minus 100 RPM from desired idle.
Throttle Position (TP) is 0%.
Short term integrator is between -20% and +20%.
The catalyst test will abort if the vehicle falls out side the conditions listed below while the test is running:
Engine speed is plus or minus 125 RPM from desired idle.
Throttle Position (TP) is 0%.
Short term integrator is between -20% and +20%.
The catalyst test may abort due to a change in engine load (i.e., A/C, coolant fan). If this problem occurs use the scan tool to force the cooling fans on then repeat the test.

Important
When using the scan tool to force the cooling fans on use the next list and previous list soft keys to enter the catalyst data list. If the catalyst data list is not entered this way the cooling fan control will be canceled.


More than 6 tests may have to be attempted to get 6 completed tests. An aborted test counts as an attempted test.
The number of attempt tests is limited to 18 per ignition cycle.
After returning to an idle the HO2S 1 signal may stay rich or lean for several seconds causing the test to be delayed.
Poor connection at PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the fault.

DTC P0507 Idle Speed High




Circuit Description
The PCM controls engine idle speed by adjusting the position of the Idle Air Control (IAC) motor pintle. The IAC is a bi-directional motor driven by two coils. The PCM sends pulses (steps) to the IAC to extend or retract the IAC pintle into a passage in the throttle body to decrease or increase air flow. The commanded IAC position (displayed in counts) can be monitored on the scan tool; a higher number of counts indicates more commanded airflow (pintle retracted) This method allows highly accurate control of idle speed and quick response to changes in engine load. If the PCM detects a condition where too low of an idle speed is present and the PCM is unable to adjust idle speed by increasing the IAC counts, DTC P0507 will set indicating a problem with the idle control system.

Conditions for Setting the DTC
No TP sensor, EVAP system, misfire, IAT sensor, MAP sensor, Fuel Trim, Fuel Injector, EGR Pintle, ECT sensor, CKP sensor, VSS, or MAF sensor DTCs are set.
System voltage is between 9 and 16 volts.
Baro is greater than 65 kPa.
Engine Coolant Temperature is greater than 70°C (158°F).
The engine has been running for at least 2 minutes.
Vehicle Speed is less than 5 km/h (3 mph).
Intake Air Temperature is greater than -18°C (0°F).
The throttle is closed.
Engine Speed is more than 175 RPM higher than Desired Idle.
The conditions are present for longer than 15 seconds.
Action Taken When the DTC Sets
The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic test has been run and failed.
The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.
Conditions for Clearing the MIL/DTC
The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
The DTC can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed.
Diagnostic Aids
Check for the following conditions:

Poor connection at the PCM or IAC motor - Inspect harness connectors for the following conditions:
Backed out terminals.
Improper mating.
Broken locks.
Improperly formed or damaged terminals.
Poor terminal to wire connection.
Damaged harness -- Inspect the wiring harness for damage.
Vacuum leak -- Check for a condition that causes a vacuum leak, such as disconnected or damaged hoses, leaks at EGR valve and EGR pipe to intake manifold, leaks at throttle body, faulty or incorrectly installed CRANKCASE VENTILATION valve, leaks at intake manifold, etc.
Throttle body -- Check for a sticking throttle plate. Also inspect the IAC passage for deposits or objects which will not allow the IAC pintle to fully extend.

[hockeyman]

damn!

[Coriya71]

:D

[joe01V6]

stop going to autozone!!!!!!!!! these retards dont know dick, believe me. i work there. they are tought to bull**** their way around everything. do u really think these dip****s know whats is really wrong with your car? nop they are just there to sell u the parts. none of them ever attended any training on cars. the only training they get is how to sell the most parts and the highest priced parts. i hate autozone. its like cult. i cant wait until i find another job. and i have been there a year to see it all. f_ck autozone>

[HBHRacing]

^ dood.. it's a free scan. Chill. no one is talking about buying anything from them.

[hockeyman]

Originally posted by joe01V6:
stop going to autozone!!!!!!!!! these retards dont know dick, believe me. i work there. they are tought to bull**** their way around everything. do u really think these dip****s know whats is really wrong with your car? nop they are just there to sell u the parts. none of them ever attended any training on cars. the only training they get is how to sell the most parts and the highest priced parts. i hate autozone. its like cult. i cant wait until i find another job. and i have been there a year to see it all. f_ck autozone>

No, please tell us how you REALLY feel!
I know quite a few employees at autozone, and they are good at their job. I believe there are a few members here that work for autozone. If you have that much of a problem, go to pepboys, pay them their money and get your car scanned. Probably get the same results too.

[My3birds]

where did you get your info on that DTC, it was quite extensive?

[Digikiller]

I think he writes for Chilton's.


P.S. I love Autozone.....

[98Camaro3.8]

Originally posted by Digikiller:
I think he writes for Chilton's.

I think he copied out of the GM Factory Service manual. ;)