When you encounter a P1275 or P1276 “Aging of Oxygen Sensor” check engine light (CEL) error, it will require immediate attention. When your oxygen sensor fails, you do not want to risk damage to your catalytic converters.
The replacement of your catalytic converters is a very expensive and preventable problem. This repair topic comes up at many a PCA meeting.
What is an Oxygen Sensor?
Your oxygen sensors detect the level of oxygen in your exhaust gases. The oxygen sensors monitor both the oxygen levels above and below your catalytic converters. Most Porsche Boxsters have 4 oxygen sensors. 2 oxygen sensors above and 2 sensors below the catalytic converters.
The oxygen sensor (O2 Sensor) is an critical aspect of your fuel delivery system of your Porsche Boxster.
There are 2 early year models of the Porsche Boxster that were released in the UK (1997 & 1998) that are said to have only 2 oxygen sensors, but they are rare.
It is important that your fuel to oxygen mixture is adjusted accordingly so the the majority of all oxygen is burned off during the combustion process.
If the O2 Sensor detects high oxygen in the exhaust it is called a lean mixture condition. Conversely, if there is low oxygen it is called a rich condition. The pre-catalytic converter O2 sensor does the majority of the work, therefore it is more prone to failure.
In a healthy engine, the pre-catalytic convertor O2 sensors will oscillate between about 0.2 to 0.8 volts regularly (about every 1 second at idle.)
The post catalytic O2 sensor’s primary job is to monitor the effectiveness of the catalytic converter. The DME monitors the post-cat O2 sensor and compares it to the pre-cat O2 sensor. If the signals are similar, The DME will assume the catalytic converter is bad.
What to do When You Get a CEL Warning?
You need to make use of an OBD II Diagnostic Scanner. Plugin your scanner, Turn your ignition to the “ACC” setting (do not start your Boxster.) Use the scanner to read and clear the error code.
Clear the code once and if it reoccurs install new Oxygen Sensors.
What is P1275 or P1276 Aging of Oxygen Sensor?
The diagnosis of “oxygen sensor aging” helps to identify oxygen sensors that exceed emission limits because of aging.
During the diagnosis of oxygen sensor aging, the Digital Motor Electronics control module monitors the period of the sensor signal.
Digital Motor Electronics (DME) is a microprocessor-based system that controls the ignition, fuel injection, oxygen sensor, and numerous ancillary functions of your Porsche Boxster.
With an old sensor, the duration of the period is too long, i.e. it is more difficult for the sensor to diffuse oxygen into the exhaust gas. Reasons for this could be frequent driving in the lower load range (city driving, short distances, etc.) or a contaminated sensor.
Can I Ignore Aging of Oxygen Sensor?
When you first get this CEL error you can clear the CEL, however, if the CEL reoccurs you need to change the oxygen sensor.
This oxygen sensor error is telling you, is that the O2 sensor is not reacting as fast as it should. Therefore the engine computer (or DME) is not benefiting from the feedback from the O2 sensor. This can lead to your DME making bad decisions based on outdated information from the oxygen sensor.
This error results in wasting gas (poor mileage) and/or dumping of the wrong mixture into the catalytic converters which will cause them to go bad. You never want to damage your catalytic converters as it is a very expensive repair
Symptoms of an Aging 0xygen Sensor
As your 02 sensor starts to fail you may experience some of the following issues:
- Poor engine performance
- Irregular idle during warm-up of the engine
- Irregular idle when the engine is warmed up
- The engine will not accelerate or backfires
- The engine has a high fuel consumption
- driving performance is weak or hesitates
- CO concentration at idle is too high or too low.
- Check engine light (CEL) is encountered
What Side is Bank 1 on Porsche Boxster?
Bank 1 of a Porsche Boxster Engine is on the passenger side of a car in the USA and on the driver’s side of a UK car.
P1275 or P1276 Aging of Oxygen Sensor CEL Codes
P1275 16 Signal Delay Time for Oxygen Sensor Ageing, Bank 1 – Above/Below Limit
P1276 22 Signal Delay Time for Oxygen Sensor Ageing, Bank 2 – Above/Below Limit
The diagnosis of “oxygen sensor aging” helps to identify oxygen sensors head of TWC that lead to emission limits being exceeded because of aging. The value of the higher-level I-controller is used to detect a shift in the sensor characteristic. Within the framework of the 2-sensor oxygen sensing system, this I-controller ensures that a level of emissions that conforms with regulations can also be achieved for a sensor with a characteristic shift via the delay time of the oxygen-sensing system.
You can download a complete list of all Porsche Diagnostic Codes here.
Recommendation: Change Oxygen Sensors in Pairs
When one of your upstream or downstream oxygen sensors fails it is strongly recommended that you replace your O2 sensors in pairs (both Upstream or both Downstream). This is because the remaining slower older sensor will cause an imbalance in your engine fuel management system. This would result in poor fuel economy and possible damage to the catalytic converter.
A more accurate engine fuel management system means a better running engine.
What Oxygen Sensor Part Numbers Do I Need?
We have had an excellent experience buying the Bosch Oxygen Sensors from Amazon (especially with prime membership.)
Tools Required to Change Oxygen Sensor
1. Oxygen Sensor Wrench
You need to use an O2 sensor socket or O2 sensor wrench to remove your 02 sensors. An Oxygen sensor socket or wrench has a special slot so that you can slide the sensor wire through it. You do not want to risk stripping the senor bolt or threads. It is very common to strip the O2 sensor bolt pattern using a conventional wrench (or spanner.) NEVER use an adjustable wrench.
- Designed for all oxygen sensors with 7/8 inch(22 mm) hex
- Flex head offers needed clearance for removal or installation of oxygen sensors when it is positioned close to the floorboard or when leverage is needed around an exhaust pipe
- Oxygen Sensor Wrench 22mm; O2 Sensor Wrench 7/8"
- Flexible O2 sensor wrench works around the exhaust
- Perfect tool set for removing, inspecting, replacing and installing heated and non heated oxygen sensors and vacuum switches on most vehicles with computer-controlled engines
- 3 types of universal socket wrenchs cover various situations of oxygen sensor location
2. Penetrating Oil
O2 sensors have gone through many heat cycles and will become seized or fused to the exhaust pipe. You need penetrating oil to help loosen up your O2 sensors. Give your O2 sensors liberal spraying and wait a good 15 minutes to start the removal.
3. Mechanic Gloves
Save your skin and wear a good pair of mechanics gloves. This will help protect your hands, keep them clean and improve your grip.
4. Copper Anti Seize Grease
The new Bosch Oxygen Sensors come with a pre-treatment of anti-seize grease. You must use a small dab of copper anti-seize grease on your O2 sensor threads. This will help with your installation and future removal of the O2 sensor.
Steps To Replace Your Oxygen Sensor
- Do this when your engine is cool and not hot or risk burning your hands.
- You will need to Jack Up your Porsche Boxster or use Ramps. Ramps may not give you enough clearance for full access. Take the time to jack up your Boxster securely and ensure it is stable and that you are using a great set of jack stands.
- Locate your failed Oxygen Sensor. Locate your secondary paired O2 Sensor. Spray both of your O2 Sensor nuts with some good penetrating oil.
- Take a 15-minute break.
- Return to your 02 Sensor and disconnect the electrical connection for your O2 Sensor.
- Wrench off the O2 Sensor.
NOTE: In severe cases when you are unable to wrench off the O2 Sensor, you will need to heat your exhaust pipe. Never heat the O2 Sensor directly. Heat the location where the O2 Sensor meets the pipe. This will allow the pipe to expand and the O2 Sensor to remain contracted. As a result, your O2 Sensor will become unseized.
- Install the New O2 Sensor and ensure that your New O2 Sensor threads are dabbed with copper anti-seize grease.
- Repeat steps 4-6 for the second O2 Sensor.
From YouTube Fixing the P1275 or P1276 Aging of Oxygen Sensor Error
Take the time to review these videos and it will make your repair a snap!
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Oxygen Sensor FAQ
If your car has 4 oxygen sensors and 1 of your upstream or downstream oxygen sensors fails. It is recommended that you replace both the sensors as a pair (upstream or downstream.) Failure to change the sensors as a pair will result in an imbalance of engine fuel management system and lead to poor gas mileage or a damage to your catalytic converter.
Last update on 2021-10-18 / Affiliate links / Images from Amazon Product Advertising API