Symptoms

The symptoms of a P2096 code vary depending on the component or system causing the fuel trim disturbance. Not all will be present at the same time.

• Malfunction Indicator Light (MIL) illumination with P2096 DTC set
• Rough idle
• Poor fuel economy
• Poor acceleration
• Misfire
• Hot cherry red catalytic converter
• Possible detonation (knocking/pre-ignition)
• Additional codes associated with P2096

Potential Causes

Causes

of this DTC may include:

Low fuel pressure caused by a clogged filter, failing fuel pump, faulty fuel pressure regulator, or clogged or leaking injectors.
Engine running poorly due to misfiring plugs. Many engines have misfire codes to indicate the affected cylinder, such as P0304 for cylinder number 4.
A significant vacuum leak would allow a massive amount of unmeasured air into the intake manifold, resulting in a too-lean mixture.
A major air leak at or near the number one oxygen sensor would also cause a lean mixture.
A plugged converter will cause many drivability issues and set this code. A heavily clogged converter will prevent the engine from increasing RPM under load. Look for a code such as P0420 – catalytic converter efficiency below threshold if the converter indicates a faulty converter.
A faulty oxygen sensor. This will set a code itself; however, a faulty oxygen sensor does not automatically condemn the sensor. The code simply means the sensor signal was not within specifications. An air leak or one of the items above will cause an incorrect signal. There are numerous O2 codes related to O2 performance that give a clue to the problematic area.
The mass airflow sensor will also cause this problem. It would be accompanied by a code such as P0100 – Mass Air Flow Circuit Malfunction. The mass airflow sensor is a hot wire that detects the volume of air entering the intake manifold. The computer uses this information to control the fuel mixture.
Rusty exhaust systems, cracked exhaust manifolds, or damaged or missing gaskets or donuts will cause air leaks.
To make a point regarding cause and effect on vehicles, consider this scenario. A simple air leak upstream of the number one oxygen sensor adds extra air to the mixture not measured by the computer. The oxygen sensor reports a lean mixture due to the unmeasured air.

Immediately, the computer enriches the mixture to prevent a lean mixture from causing damage due to detonation, among other factors. The unnecessarily rich mixture begins to foul the plugs, contaminate the oil, overheat the converter, and reduce fuel economy. These are just a few of the things that happen under these circumstances.

Diagnostic and Repair Procedures

• It is wise to go online and acquire the Technical Service Bulletins (TSBs) associated with these codes and a description. Although all vehicles suffer from similar causes, some may have a service history of issues with a particular component related to this code.
• If you have access to an advanced diagnostic scan tool such as Tech II or Snap-On Vantage, it will save you a lot of time. The scanner has the ability to graph and display real-time numerical information from each sensor’s performance. It will show the oxygen sensors in operation to easily recognize one that is malfunctioning.
• Jeeps and some Chrysler products seem to suffer from poor electrical connectors, so inspect them carefully. Additionally, Jeeps have had several PCM updates on recent models. Reprogramming updates along with replacing the oxygen sensor for any reason are covered by the 8-year/80,000-mile warranty. To check if the update has been done, look beside or behind the battery and there will be a serial number with the computer update date. If it hasn’t been done, it is free for the period mentioned above.
• Connect the code scanner to the OBD port under the dashboard. Turn the key to “On” with the engine off. Press the “Read” button and the codes will display. Record all additional codes on the attached code sheet. Focus your attention on these codes first.
• Instead of additional codes matching the P2096 or P2098 code, test drive the vehicle and look for the telltale symptoms. Fuel contamination will cause this code. Refill with a higher octane fuel.
• If the vehicle displays very little power and struggles to accelerate, look under the vehicle with the engine running. A clogged converter will typically glow red.
• Check the engine for vacuum leaks between the mass airflow sensor and the intake manifold. Often, leaks sound like a whistle. Repair the leaks and clear the code.
• If the engine is misfiring and there is no code, determine which cylinder is misfiring. If the exhaust manifold is visible, spray or pour a small amount of water on each cylinder’s exhaust port. The water evaporates immediately on the good cylinders and slowly on the misfiring cylinder. If this cannot be done, remove the plugs and check their condition.
• Look at the spark plug wires to ensure they are not burnt or resting on the exhaust.
• Inspect the exhaust system. Look for rust holes, missing gaskets, cracks, or looseness. Lift the vehicle and with a 7/8-inch wrench, ensure the oxygen sensor is tight. Inspect the wiring harness and connector.
• If a code for the mass airflow sensor appears, check its connector. If it is okay, replace the MAF sensor.
• Replace the oxygen sensor downstream of the catalytic converter on the engine side by cylinder number 1 for code P2096. Additionally, if an oxygen sensor code indicates “heater circuit malfunction,” the sensor is most likely faulty.

Severity and Symptoms

A P2097 code means the post-catalytic converter O2 sensor has detected a rich exhaust condition. Fuel efficiency may be compromised and the code should be considered severe.

Symptoms of a P2097 code may include:

• Decreased fuel efficiency
• Lack of overall engine performance
• Other associated diagnostic trouble codes may be stored
• Service engine soon light illumination

Possible causes of this engine code include:

• Faulty catalytic converter
• Faulty mass airflow or manifold absolute pressure sensor
• Faulty O2 sensor(s)
• Burned, chafed, broken, or disconnected wiring and/or connectors
• Engine exhaust leaks

Diagnostic and Repair Procedures

A good starting point is always to check for technical service bulletins (TSBs) for your specific vehicle. Your issue may be a known problem with a known fix released by the manufacturer and can save you time and money when diagnosing.

A diagnostic scan tool, a digital volt ohm meter (DVOM), and a vehicle service manual will be helpful in diagnosing a P2097 code. AllData (DIY) is also an excellent source for system wiring diagrams and other application-specific information.

The engine must be running efficiently before attempting to diagnose this code. Misfire codes, throttle position sensor codes, manifold absolute pressure codes, and mass airflow sensor codes should be addressed before attempting to diagnose a P2097 code.

Begin with a visual inspection of the system wiring harnesses and connectors. With a P2097, I would pay particular attention to harnesses that are routed near hot exhaust pipes and manifolds, as well as those routed near sharp edges (cylinder head).

Connect the scan tool to the diagnostic port and retrieve all stored trouble codes and freeze frame data. Write this information down. This may prove helpful if this turns out to be an intermittent code. Intermittent codes can be more difficult to diagnose.

If the P2097 immediately resets, start the engine and allow it to reach normal operating temperature. Let it idle (with transmission in neutral or park). Use the scan tool to observe the O2 sensor input data. Limiting the data stream scope to include only relevant data will allow you to get a faster response. Observe the downstream O2 sensor signal. If the engine is running efficiently, the downstream O2 sensor data should reach a midpoint and settle there.

The DVOM can be used to check the resistance of the O2 sensor in question, as well as the voltage signals and grounds for the O2 sensor circuit. Disconnect associated controllers before attempting to test system circuit resistance with the DVOM.

Additional diagnostic notes:

• The downstream O2 sensor should not switch as frequently as the upstream sensors (once the PCM has entered closed loop operation). If the downstream sensor continues to switch as frequently as the upstream sensor, after the engine has warmed up and the PCM has entered closed loop operation, suspect a faulty catalytic converter
• When catalytic converter replacement is necessary, consider an OEM quality component. Rebuilt or lower quality replacement converters typically fail quickly and repeatedly

Symptoms

The symptoms of a P2098 code vary depending on the component or system causing the fuel trim disturbance. Not all will be present at the same time.

• Malfunction Indicator Lamp (MIL) illuminated with P2098 DTC stored
• Rough idle
• Poor fuel economy
• Poor acceleration
• Misfire
• Hot cherry red catalytic converter
• Possible engine knock (detonation / pre-ignition)
• Additional codes associated with P2098

Potential Causes

Causes

of this DTC may include:

• Low fuel pressure caused by a clogged filter, failing fuel pump, faulty fuel pressure regulator, or clogged or leaking injectors.
• Engine running poorly due to misfiring spark plugs. Many engines have misfire codes to indicate the affected cylinder, such as P0307 for cylinder number 7.
• A significant vacuum leak would allow a massive amount of unmetered air into the intake manifold, resulting in a mixture that is too lean.
• A significant air leak at or near the number one oxygen sensor would also cause a lean mixture.
• A plugged catalytic converter will cause many drivability issues and set this code. A severely clogged converter will prevent the engine RPM from increasing under load. Look for a code such as P0421 – catalytic converter efficiency below threshold if the converter indicates a faulty converter.
• A faulty oxygen sensor. This will set a code itself; however, an oxygen sensor code does not automatically condemn the sensor. The code simply means the sensor’s signal was not within specifications. An air leak or one of the items above will cause an incorrect signal. There are numerous O2 codes related to O2 performance that give a clue to the problematic area.
  The Mass Air Flow (MAF) sensor will also cause this problem. It would be accompanied by a code such as P0100 – Mass Air Flow Circuit Malfunction. The MAF sensor is a hot wire that detects the volume of air entering the intake manifold. The computer uses this information to control the fuel mixture.
• Rusted exhaust systems, cracked exhaust manifolds, or damaged or missing gaskets or donuts will cause air leaks.
• To make a point about cause and effect on vehicles, consider this scenario. A simple air leak upstream of the number one oxygen sensor adds extra air to the mixture not measured by the computer. The oxygen sensor reports a lean mixture due to the unmetered air.

Immediately, the computer enriches the mixture to prevent a lean mixture from causing damage due to knocking, among other factors. The unnecessarily rich mixture begins to foul the spark plugs, contaminate the oil, overheat the converter, and reduce fuel economy. These are just a few of the things that happen under these circumstances.

Diagnostic and Repair Procedures

It is wise to go online and acquire the Technical Service Bulletins (TSBs) associated with these codes and a description. Although all vehicles suffer from similar causes, some may have a service history of problems with a particular component associated with this code.

If you have access to an advanced diagnostic scan tool such as a Tech II or Snap-On Vantage, it will save you a lot of time. The scanner has the ability to graphically represent and display real-time numerical information from each sensor’s performance. It will show the oxygen sensors in operation to easily recognize one that is malfunctioning.

Jeeps and some Chrysler products seem to suffer from poor electrical connectors, so inspect them carefully. Additionally, Jeeps have had several PCM updates on recent models. Reprogramming the updates along with replacing the oxygen sensor for any reason is covered by the 8-year/80,000-mile warranty. To check if the update has been done, look beside or behind the battery and there will be a serial number with the computer update date. If it hasn’t been done, it is free for the period mentioned above.

• Connect the code scanner to the OBD port under the dashboard. Turn the key to “On” with the engine off. Press the “Read” button and the codes will display. Record all additional codes on the attached code sheet. Focus your attention on these codes first.
• In the absence of additional codes matching P2096 or P2098, test drive the vehicle and look for the telltale symptoms. Fuel contamination will cause this code. Refill with a higher octane fuel.
• If the vehicle displays very little power and struggles to accelerate, look underneath the vehicle with the engine running. A clogged converter will typically glow red.
• Check the engine for vacuum leaks between the Mass Air Flow sensor and the intake manifold. Often, leaks sound like a whistle. Repair the leaks and clear the code.
• If the engine is misfiring and there is no code, determine which cylinder is misfiring. If the exhaust manifold is visible, spray or pour a small amount of water on each cylinder’s exhaust port. The water will evaporate immediately on the good cylinders and slowly on the misfiring cylinder. If this cannot be done, remove the spark plugs and check their condition.
• Look at the spark plug wires to ensure they are not burnt or resting on the exhaust.
• Inspect the exhaust system. Look for rust holes, missing gaskets, cracks, or looseness. Lift the vehicle and with a 7/8-inch wrench, ensure the oxygen sensor is tight. Inspect the wiring harness and connector.
• If a code for the Mass Air Flow sensor appears, check its connector. If it is okay, replace the MAF sensor.
• Replace the oxygen sensor that is downstream of the catalytic converter on the side of the engine that does not contain cylinder #1. Also, if an oxygen sensor code indicates “heater circuit malfunction,” the sensor is most likely faulty.

Severity and Symptoms

A P2099 code means the post-catalytic converter oxygen sensor on bank 2 has detected a rich exhaust condition. Fuel efficiency may be compromised and the code should be considered severe.

Symptoms of a P2099 code may include:

• Decreased fuel efficiency
• General lack of engine performance
• Other associated diagnostic trouble codes may be stored
• Illumination of the service engine soon light

Causes

Possible causes of this engine code include:

• Faulty bank 2 catalytic converter
• Faulty mass airflow sensor or manifold absolute pressure sensor
• Faulty bank 2 oxygen sensor(s)
• Burned, chafed, broken, or disconnected wiring and/or connectors
• Engine exhaust leaks

Diagnostic and Repair Procedures

A good starting point is always to check the technical service bulletins (TSBs) for your specific vehicle. Your issue may be a known problem with a known fix published by the manufacturer and can save you time and money when diagnosing.

A diagnostic scanner, a digital volt ohmmeter (DVOM), and a vehicle service manual will be helpful in diagnosing a P2099 code. AllData (DIY) is also an excellent source for system wiring diagrams and other application-specific information.

The engine must be running efficiently before attempting to diagnose this code. Misfire codes, throttle position sensor codes, manifold absolute pressure codes, and mass airflow sensor codes should be addressed before attempting to diagnose a P2099 code.

Begin with a visual inspection of the system wiring harnesses and connectors. With a P2099, I would pay particular attention to harnesses that are routed near hot exhaust pipes and manifolds, as well as those routed near sharp edges (cylinder head).

Connect the scanner to the diagnostic port and retrieve all stored trouble codes and freeze frame data. Write this information down. This may prove helpful if this turns out to be an intermittent code. Intermittent codes can be more difficult to diagnose.

If the P2099 immediately resets, start the engine and allow it to reach its normal operating temperature. Let it idle (with the transmission in neutral or park). Use the scanner to observe the input data from the bank 2 oxygen sensor. Limiting the scope of the data stream to include only relevant data will allow you to get a faster response. Observe the downstream oxygen sensor signal. If the engine is running efficiently, the downstream oxygen sensor data should reach a midpoint and settle there.

The DVOM can be used to check the resistance of the oxygen sensor in question, as well as the voltage signals and grounds for the oxygen sensor circuit. Disconnect associated controllers before attempting to test system circuit resistance with the DVOM.

Additional diagnostic notes:

• The downstream oxygen sensor should not switch as frequently as the upstream sensors (once the PCM has entered closed-loop operation). If the downstream sensor continues to switch as frequently as the upstream sensor, after the engine has warmed up and the PCM has entered closed-loop operation, suspect a faulty catalytic converter
• When catalytic converter replacement is necessary, consider an OEM quality component. Rebuilt or inferior quality replacement converters typically fail quickly and repeatedly

How severe is this DTC?

A stored P209A code should be considered serious and addressed as soon as possible. The SCR system could be disabled because of this. Catalyst damage could occur if the conditions that contributed to the code being stored are not corrected in a timely manner.

What are some of the symptoms of the code?

Symptoms of a P209A fault code may include:

• Reduced fuel efficiency
• Excessive black smoke from the vehicle’s exhaust
• Decreased engine performance
• Other SCR-related codes

What are some common causes of the code?

Causes

of this code may include:

• Faulty reductant air pressure sensor (B)
• Open or shorted circuits in the reductant injection air pressure sensor system
• Faulty SCR controller / PCM or programming error

What are the troubleshooting steps for P209A?

Ensure that the reductant supply/regeneration system is not losing pressure (internally or externally). Activate the pump to create pressure and inspect the system for external leaks. Use a fuel pressure tester to manually monitor the reductant system pressure. Check the supply pump and injector for leaks. If leaks are discovered (internal or external), they must be repaired before continuing diagnosis.

A diagnostic scanner, digital volt/ohmmeter (DVOM), and vehicle-specific diagnostic information source will be needed to diagnose a P209A code.

You can use your vehicle information source to locate a Technical Service Bulletin (TSB) that matches the vehicle’s year, make, and model; as well as engine size, stored codes, and presented symptoms. If you find one, it could provide helpful diagnostic information.

Use the scanner (connected to the vehicle’s diagnostic connector) to retrieve all stored codes and relevant freeze frame data. It’s a good idea to write down this information before clearing the codes, then test drive the vehicle until the PCM enters readiness mode or the code resets.

If the PCM enters readiness mode at this point, the code is intermittent and may be much more difficult to diagnose. If this is the case, the conditions that contributed to the code being stored may need to worsen before an accurate diagnosis can be made.

If the code immediately resets, the next step in your diagnosis will require you to search your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, and component testing procedures/specifications.

Step 1

Use the DVOM to test the reductant injection system pressure sensors according to manufacturer specifications. Components that do not test within allowed parameters should be considered defective.

Step 2

If reductant injection pressure is within specifications, the P209A code persists, and the sensor in question is operational, use the DVOM to test the input and output signal circuits between the sensors and the PCM/SCR controller. Disconnect all controllers before using the DVOM for testing.

Reductant injector sensor codes are often attributed to internally leaking supply pumps

How serious is this DTC?

A stored P209B code should be considered serious and addressed as soon as possible. The SCR system could be disabled because of this. Catalyst damage could occur if the conditions that contributed to the code being stored are not corrected in a timely manner.

What are some of the symptoms of the code?

Symptoms of a P209B fault code may include:

• Reduced energy efficiency
• Excessive black smoke from the vehicle’s exhaust
• Decreased engine performance
• Other SCR-related codes

What are some common causes of the code?

Causes

of this code may include:

• Faulty reductant air pressure sensor (B)
• Open or shorted circuits in the reductant injection air pressure sensor system
• Faulty SCR controller/PCM or programming error

What are the troubleshooting steps for P209B?

Ensure the reductant supply/regeneration system is not losing pressure (internally or externally). Activate the pump to create pressure and inspect the system for external leaks. Use a fuel pressure tester to manually monitor the reductant system pressure. Check the supply pump and injector for leaks. If leaks are found (internal or external), they must be repaired before continuing diagnosis.

A diagnostic scanner, digital volt/ohmmeter (DVOM), and vehicle-specific diagnostic information source will be needed to diagnose a P209B code.

You can use your vehicle information source to locate a technical service bulletin (TSB) that matches the vehicle’s year, make, and model; as well as engine size, stored codes, and presented symptoms. If you find one, it may provide helpful diagnostic information.

Use the scanner (connected to the vehicle’s diagnostic connector) to retrieve all stored codes and relevant freeze frame data. It’s a good idea to record this information before clearing the codes, then test drive the vehicle until the PCM enters readiness mode or the code resets.

If the PCM enters readiness mode at this point, the code is intermittent and may be much more difficult to diagnose. If this is the case, the conditions that contributed to the code being stored may need to worsen before an accurate diagnosis can be made.

If the code immediately resets, the next step in your diagnosis will require you to search your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, and component testing procedures/specifications.

Step 1

Use the DVOM to test the reductant injection system pressure sensors according to manufacturer specifications. Components that do not test within allowable parameters should be considered faulty.

Step 2

If reductant injection pressure is within specifications, the P209B code persists, and the sensor in question is operational, use the DVOM to test the input and output signal circuits between the sensors and the PCM/SCR controller. Disconnect all controllers before using the DVOM for testing.

Reductant injector sensor codes are often attributed to internally leaking supply pumps

How serious is this DTC?

A stored P209C code should be considered serious and addressed as soon as possible. The SCR system could be disabled because of this. Catalyst damage could occur if the conditions that contributed to the code being stored are not corrected in a timely manner.

What are some of the symptoms of the code?

Symptoms of a P209C fault code may include:

• Reduced fuel efficiency
• Excessive black smoke from the vehicle’s exhaust
• Decreased engine performance
• Other SCR-related codes

What are some common causes of the code?

Causes

of this code may include:

• Faulty reductant air pressure sensor (B)
• Open or shorted circuits in the reductant injection air pressure sensor system
• Faulty SCR controller/PCM or programming error

What are the troubleshooting steps for P209C?

Ensure the reductant supply/regeneration system is not losing pressure (internally or externally). Activate the pump to create pressure and inspect the system for external leaks. Use a fuel pressure tester to manually monitor the reductant system pressure. Check the supply pump and injector for leaks. If leaks are discovered (internal or external), they must be repaired before continuing diagnosis.

A diagnostic scanner, digital volt/ohmmeter (DVOM), and vehicle-specific diagnostic information source will be needed to diagnose a P209C code.

You can use your vehicle information source to locate a technical service bulletin (TSB) that matches the vehicle’s year, make, and model; as well as engine size, stored codes, and presented symptoms. If you find one, it could provide helpful diagnostic information.

Use the scanner (connected to the vehicle’s diagnostic connector) to retrieve all stored codes and relevant freeze frame data. It’s a good idea to record this information before clearing the codes, then test drive the vehicle until the PCM enters readiness mode or the code resets.

If the PCM enters readiness mode at this point, the code is intermittent and may be much more difficult to diagnose. If this is the case, the conditions that contributed to the code being stored may need to worsen before an accurate diagnosis can be made.

If the code immediately resets, the next step in your diagnosis will require you to search your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, and component testing procedures/specifications.

Step 1

Use the DVOM to test the reductant injection system pressure sensors according to manufacturer specifications. Components that do not test within allowed parameters should be considered defective.

Step 2

If reductant injection pressure is within specifications, the P209C code persists, and the sensor in question is operational, use the DVOM to test the input and output signal circuits between the sensors and the PCM/SCR controller. Disconnect all controllers before using the DVOM for testing.

Reductant injector sensor codes are often attributed to internally leaking supply pumps

How serious is this DTC?

A stored P209D code should be considered serious and addressed as soon as possible. The SCR system could be disabled because of this. Catalyst damage could occur if the conditions that contributed to the code being stored are not corrected in a timely manner.

What are some of the symptoms of the code?

Symptoms of a P209D trouble code may include:

• Reduced fuel efficiency
• Excessive black smoke from the vehicle’s exhaust
• Decreased engine performance
• Other SCR-related codes

What are some common causes of the code?

Causes of this code may include:

• Faulty reductant air pressure sensor (B)
• Open or shorted circuits in the reductant injection air pressure sensor system
• Faulty SCR controller/PCM or programming error

What are the troubleshooting steps for P209D?

Ensure the reductant supply/regeneration system is not losing pressure (internally or externally). Activate the pump to create pressure and inspect the system for external leaks. Use a fuel pressure tester to manually monitor the reductant system pressure. Check the supply pump and injector for leaks. If leaks are discovered (internal or external), they must be repaired before continuing diagnosis.

A diagnostic scanner, digital volt/ohmmeter (DVOM), and vehicle-specific diagnostic information source will be needed to diagnose a P209D code.

You can use your vehicle information source to locate a technical service bulletin (TSB) that matches the vehicle’s year, make, and model; as well as engine size, stored codes, and presented symptoms. If you find one, it could provide helpful diagnostic information.

Use the scanner (connected to the vehicle’s diagnostic connector) to retrieve all stored codes and relevant freeze frame data. It’s a good idea to record this information before clearing the codes, then test drive the vehicle until the PCM enters readiness mode or the code resets.

If the PCM enters readiness mode at this point, the code is intermittent and may be much more difficult to diagnose. If this is the case, the conditions that contributed to the code being stored may need to worsen before an accurate diagnosis can be made.

If the code immediately resets, the next step in your diagnosis will require you to search your vehicle information source for diagnostic flowcharts, connector pinout diagrams, connector face views, and component testing procedures/specifications.

Step 1

Use the DVOM to test the reductant injection system pressure sensors according to manufacturer specifications. Components that do not test within allowable parameters should be considered defective.

Step 2

If reductant injection pressure is within specifications, the P209D code persists, and the sensor in question is operational, use the DVOM to test the input and output signal circuits between the sensors and the PCM/SCR controller. Disconnect all controllers before using the DVOM for testing.

Reductant injector sensor codes are often attributed to internally leaking supply pumps