DaveV

car is running all ok but engine light is on steady, any one had this problem ? and what if any was the fixture thx.

irok

when the ECM detects no output signal from the cam position sensor it sets P0340 DTC.:disreguard I read the DTC number in your post. Bill's post following this is what you need to look at

Bill Dearborn

Not sure where that info about the camshaft sensor came from but it is wrong. That code has to do with catalyst efficiency on bank 2 (passenger side). Could be a bad cat or the sensor after the cat is bad. Here is the diagnostic info from the Service Manual:

DTC P0420 or P0430
Diagnostic Instructions
• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors
DTC P0420: Catalyst System Low Efficiency Bank 1

DTC P0430: Catalyst System Low Efficiency Bank 2
Circuit/System Description
Important: A new converter with less than 100 miles on it may set DTC P0420 or P0430 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 hour may correct the condition.

A 3-way catalytic converter (TWC) controls emissions by converting hydrocarbons (HC) and carbon monoxide (CO) into carbon dioxide (CO2), and oxides of nitrogen (NOx) into nitrogen. The TWC also stores oxygen. When the listed idle conditions follow the listed driving conditions the Catalyst System Efficiency test will run. The engine control module (ECM) monitors this oxygen storage capacity by comparing the pre and post-catalyst oxygen sensor signals while adding and subtracting fuel during specific idle conditions. The ECM compares the pre and post-catalyst oxygen sensor signals to determine if the oxygen storage capacity of the catalyst is degraded.

Conditions for Running the DTC
Driving Conditions
• DTCs P0030, P0031, P0036, P0037, P0038, P0068, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P0130, P0131, P0132, P0133, P0134, P0135, P0136, P0137, P0138, P0140, P0141, P0171, P0172, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0300, P0315, P0326, P0327, P0336, P0340, P0341, P0442, P0446, P0452, P0453, P0455, P0496, P0500 (manual transmission only), P0502, P0506, P0507, P0601, P0602, P0606, P0641, P0722, P0723, P1133, P1134, P1516, P1621, P2135, P2138, P2176 are not set.

• The engine has been running for more than 2 minutes.
• The vehicle has been driven at more than 1,000 RPM for more than 10 seconds.
• The vehicle is in Closed Loop.
• The vehicle has Fuel Trim Learn enabled.
• The Engine Coolant Temperature (ECT) parameter is between 45-128°C (113-262°F).
• The Barometric Pressure (BARO) parameter is more than 70 kPa.
• The Catalytic Converter Calculated Temperature parameter is greater than or equal to 375°C (707°F).
• The Intake Air Temperature (IAT) parameter is between -20 and +85°C (-4 and +185°F).
• The battery voltage is more than 11 volts.
Idle Conditions
• The vehicle speed is less than 3.2 km/h (2 mph).
• For automatic transmissions, the transmission is in Reverse, Drive, or Low.
• The Throttle Position (TP) parameter is 2 percent or less.
• The short term fuel trim (FT) is between -10 and +10 percent.
• This diagnostic attempts one test during each valid idle period when the above conditions have been met. This diagnostic attempts up to 6 tests during each drive cycle.
Conditions for Setting the DTC
• The ECM has determined the catalyst efficiency has degraded below a calibrated threshold.
• This diagnostic may conclude in one test attempt. However, this diagnostic may require as many as 18 test attempts, which would require at least 3 drive cycles. Each test attempt may conclude within approximately 1 minute.

Action Taken When the DTC Sets
DTCs P0420 and P0430 are Type A DTCs.

Conditions for Clearing the MIL/DTC
DTCs P0420 and P0430 are Type A DTCs.

Reference Information
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference
Diagnostic Trouble Code (DTC) List - Vehicle

Circuit/System Verification
Notice: Refer to Three-Way Catalytic Converter Damage Notice in the Preface section.

Notice: Refer to Heated Oxygen Sensor Resistance Learn Reset Notice in the Preface section.

Important: A new converter with less than 100 miles on it may set DTC P0420 or P0430 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 hour may correct the condition.

If any other DTCs are set perform those diagnostics first.
Inspect for the following conditions, which may cause a catalytic converter to degrade:
• An engine misfire
• High engine oil or high coolant consumption
• Retarded spark timing
• A weak or poor spark
• A lean fuel mixture
• A rich fuel mixture
• A damaged oxygen sensor or wiring harness
• The catalyst test may abort if the vehicle falls outside the conditions for running the DTC.
• A catalyst may be temporarily degraded if a fuel with high sulfur content has been used. Drive the vehicle at highway speeds for 10 minutes and retest the converter.

Operate the vehicle within the Conditions for Running the DTC.
⇒ If the DTC fails this key cycle, continue with this procedure.

Inspect the catalytic converter for the following conditions:
• Dents
• A severe discoloration caused by excessive temperatures
• Road damage
• An internal rattle caused by damaged catalyst substrate
• Restrictions
⇒ If a condition is found, replace the catalytic converter.
Inspect the exhaust system for the following conditions:
• Leaks
• Physical damage
• Loose or missing hardware
• Properly torqued HO2S
• Restrictions
⇒ If a condition is found, repair the exhaust system.
Inspect the post catalyst HO2S for the following conditions:
• A grounded wiring harness
• Damage
⇒ If a condition is found, replace the post catalyst HO2S.
⇒ If no physical condition is detected, replace the catalytic converter.

Repair Instructions
Important: A new converter with less than 100 miles on it may set DTC P0420 or P0430 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 hour may correct the condition.

• Exhaust Manifold Replacement - Left Side
• Exhaust Manifold Replacement - Right Side
• Heated Oxygen Sensor Replacement - Bank 1 Sensor 2
• Heated Oxygen Sensor Replacement - Bank 2 Sensor 2
• Exhaust Leakage
• Restricted Exhaust

Repair Verification
Clear the DTCs.
Allow the engine coolant temperature to reach 70°C (156°F).
• Place the gear selector in Park, Neutral for manual.
• Set the parking brake.
Press and hold the service brake.
Run the engine for 6 minutes at 2500 RPM.
Allow engine speed to return to idle speed, then place gear selector into Drive, or apply clutch pedal for manual.
After 2 minutes verify that DTC P0420 or P0430 have passed or failed this ignition cycle.
⇒ If not passed or failed this ignition cycle, the test aborted resulting in an inconclusive test result. The above test may need to be repeated up to 5 more times during this drive cycle. The first test should be run after the initial warm up period of 6 minutes. Between subsequent tests maintain 2,500 RPM for 2 minutes.

If 6 tests have been attempted and the DTC has not run or passed during this key cycle, turn the key to OFF for 30 seconds, then run the procedure a second time.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

If the car's In Service Date is less than 8 years ago and the mileage is less than 80K miles and the cat is bad it will be covered under the emissions warranty.

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Emission Control Systems Warranty
This section outlines the Emission Warranty that GM provides for your vehicle, in accordance with the U.S. Federal Clean Air Act. Defects in material or workmanship in GM emission parts may also be covered by the "Bumper-to-Bumper" coverage. There may be additional coverage on GM diesel engine vehicles. In any case, the warranty with the broadest coverage applies.

What Is Covered
The parts covered under the Emission Control Systems warranties are listed under "Emission Warranty Parts List" later in this section.

What Is Not Covered
The Emission Control Systems warranties obligations do not apply to conditions resulting from tampering, abuse, neglect, or improper maintenance; or any other items listed under "What is not Covered" in the New Vehicle Warranty. The "Other Terms" presented in the New Vehicle Limited Warranty also apply to the emission related warranties.

Warranty Period
Both the Emission Defect warranty and the Emission Performance warranty described below begin on the date the vehicle is first delivered or put into use and continue for a period of 2 years or 24,000 miles, whichever occurs first. If a catalytic converter or powertrain control module is found to be defective under either or these warranties, those parts are warranted for 8 years or 80,000 miles.

Emission Control Systems Warranties
Emission Defect Warranty
GM warrants to the owner the following:

• The vehicle was designed, built, and equipped so as to conform at the time of sale with the applicable regulations of the Federal Environmental Protection Agency (EPA).

• The vehicle is free from defects in material and workmanship which cause the vehicle to fail to conform with those regulations during the emission warranty period.

Emission related defects in the genuine GM parts listed under the Emission Warranty Parts List, including related diagnostic costs, parts and labor are covered by this warranty.

Emission Performance Warranty
Some states and/or local jurisdictions have established periodic vehicle Inspection and Maintenance (I/M) programs to encourage proper maintenance of your vehicle. If an EPA-approved I/M program is enforced in your area, you may also be eligible for Emission Performance Warranty coverage when all of the following conditions are met:

• The vehicle has been maintained and operated in accordance with the instructions for proper maintenance and use set forth in the Owner Manual and the Warranty and Maintenance Schedule booklets supplied with your vehicle.

• The vehicle fails an EPA-approved I/M test during the emission warranty period.

• The failure results, or will result, in the owner of the vehicle having to bear a penalty or other sanctions, including the denial of the right to use the vehicle, under local, state, or federal law.

If all of these conditions are met, GM warrants that your dealer will replace, repair, or adjust to GM specifications, at no charge to you, any of the parts listed under the "Emission Warranty Parts List" later in this section, or parts thereof, which may be necessary to cause your vehicle to conform to the applicable emission standards. Non-GM parts labeled "Certified to EPA Standards" are also covered by this warranty.

Emission Warranty Parts List
The parts that may affect your vehicle's emissions are on the following pages. These emission parts are covered under emission warranties as follows:

Powertrain Control System

ABS Control Module

Camshaft Position Actuator

Camshaft Position Actuator Valve

Coolant Level Sensor

Data Link Connector

Electronic Throttle Control (ETC) Motor

Engine Control Module (ECM)

Engine Coolant Temperature Sensor

Fast Idle Solenoid

Flexible Fuel Sensor

Fuel Control Module

Intake Air Temperature Sensor

Malfunction Indicator Lamp

Manifold Absolute Pressure Sensor

Mass Air Flow Sensor

Oil Pressure Sensor (DoD™ only)

Oxygen Sensors

Powertrain Control Module (PCM)

Programmable Read Only Memory (PROM)

Throttle Position Sensor

Throttle Position Switch

Vehicle Control Module (VCM)

Vehicle Speed Sensor

Wheel Speed Sensor

Transmission Controls and Torque Management

GMLAN (CAN) Communications Circuit

Manual Transmission Clutch Switch

Park/Neutral Switch

Torque Converter Clutch Solenoids

Torque Converter Clutch Switch

Transmission Control Module

Transmission Fluid Temperature Sensor

Transmission Gear Selection Switch (Diesel)

Transmission Internal Mode Switch

Transmission Pressure Control Solenoids

Transmission Pressure Switches

Transmission Shift Solenoids

Transmission Speed Sensors

Fuel Management System

Common Rail Assembly (6.6L DURAMAX® Diesel)

Diesel Fuel Injection Pump

Diesel Fuel Injection Pump Timing Adjust

Diesel Fuel Injector Control Module - EDU (6.6L DURAMAX® Diesel)

Diesel Fuel Temperature Sensor

Direct Fuel Injector Assembly (6.6L DURAMAX® Diesel)

Fuel Injector

Fuel Pressure Regulator

Fuel Rail Assembly

Fuel Rail Pressure Sensor

Function Block (6.6L DURAMAX® Diesel)

High Pressure Fuel Pump (SIDI)

Air Management System

Air Cleaner

Air Cleaner Diaphragm Motor

Air Cleaner Resonator

Air Cleaner Temperature Compensator Valve

Air Intake Ducts

Charge Air Control Actuator

Charge Air Control Solenoid Valve

Charge Air Control Valve

Charge Air Cooler

Charge Air Cooler Fan

Idle Air Control Valve

Idle Speed Control Motor

Intake Manifold

Intake Manifold Gasket (7/70 Only Uplander, Montana SV6, and DURAMAX® Diesel)

Intake Manifold Heater

Intake Manifold Tuning Valve

Intake Manifold Tuning Valve Relay

Supercharger Assembly

Throttle Body (Replacement Only)

Throttle Body Heater

Throttle Closing Dashpot

Turbocharger Assembly

Turbocharger Boost Sensor

Turbocharger Oil Separator

Turbocharger Thermo Purge Switch

Vacuum Pump (6.6L DURAMAX® Diesel)

Ignition System

Camshaft Position Sensor(s)

Crankshaft Position Sensor(s)

Distributor

Distributor Cap

Distributor Pick Up Coil

Distributor Rotor

Glow Plug(s) (Diesel)

Glow Plug Controller (Diesel)

Glow Plug Relay (Diesel)

Ignition Coil(s)

Ignition Control Module

Ignition Timing Adjustment

Knock Sensor

Spark Plug Wires

Spark Plugs

Catalytic Converter System

Catalytic Converter(s) and Muffler if attached as assembly

Diesel Exhaust Temperature and Pressure Sensors

Diesel Particulate Filter (DPF)

Exhaust Manifold (7/70 Only Corvette 7.0L, Equinox, Torrent, Uplander, Montana SV6, Cadillac DTS 4.6L and XLR, (Impala and Grand Prix 5.3L right side) and C/K Trucks < 14,000 GVWR 8.1L)

Exhaust Manifold with Catalytic Converter attached as assembly

Exhaust Manifold Gasket

Exhaust Pipes and/or Mufflers (when located between catalytic converters and exhaust manifold)

Positive Crankcase Ventilation System

Oil Filler Cap

PCV Filter

PCV Oil Separator

PCV Valve

Exhaust Gas Recirculation System

EGR Feed and Delivery Pipes or Cast-in Passages

EGR Valve

EGR Valve Cooler (6.6L DURAMAX® Diesel)

EGR Vacuum Pump Assembly (6.6L DURAMAX® Diesel)

Secondary Air Injection System

Air Pump

Check Valves

Evaporative Emission Control System (Gasoline Engines)

Canister

Canister Purge Solenoid Valve

Canister Vent Solenoid

Fuel Feed and Return Pipes and Hoses

Fuel Filler Cap

Fuel Level Sensor

Fuel Limiter Vent Valve

Fuel Tank(s)

Fuel Tank Filler Pipe (with restrictor)

Fuel Tank Vacuum or Pressure Sensor

Hybrid

Auxiliary Transmission Fluid Pump

Battery Cooling Fan

Battery Pack Control Module (BPCM)

Battery Pack Current Sensor

Brake Pedal Travel Sensor

Drive Motors A and B

Drive Motor A and B Resolvers

Drive Motor/Generator Control Module (DMCM - HCP, MCPA, MCPB)

Electro-Hydraulic Brake Control Module (EBCM)

Energy Storage Control Module

Fuel Filler Pipe Adapter Seal

Hybrid Batteries

Hybrid Battery Temperature Sensors

Hybrid Battery Voltage Sensors

SGCM Coolant Circuit (fan and fan relay and pump)

Starter Generator Control Module

Transmission Friction Elements

Transmission Substrate Temperature Sensor

Miscellaneous Items Used with Above Components are Covered

Belts

Boots

Clamps

Connectors

Ducts

Fittings

Gaskets

Grommets

Hoses

Housings

Mounting Hardware

Pipes

Pulleys

Sealing Devices

Springs

Tubes

Wiring

Parts specified in your maintenance schedule that require scheduled replacement are covered up to their first replacement interval or the applicable emission warranty coverage period, whichever comes first. If failure of one of these parts results in failure of another part, both will be covered under the Emission Control System Warranty.

Parts specified in your maintenance schedule as requiring scheduled replacement are covered up to their first replacement interval or the applicable emission warranty coverage period, whichever comes first. If failure of one of these parts results in failure of another part, both will be covered under the Emission Control System Warranty.

Parts specified in your maintenance schedule that require scheduled replacement are covered up to their first replacement interval or the applicable emission warranty coverage period, whichever comes first. If failure of one of these parts results in failure of another part, both will be covered under the Emission Control System Warranties.

For detailed information concerning specific parts covered by these emission control systems warranties, ask your dealer.

Bill

irok

the numbers not wrong for the cam sensor in my post but I did read the number wrong for his question. sorry for the confusion.

ls1121

depending what the real problem is but...... a tuner can tune out the rear o2 sensors.