Diagnose trouble codes (DTCs) help identify and notify problems with a vehicle’s vital components. If you want your car to be well-maintained and safe to drive, you should know what these codes mean.
An engine code P0135 indicates that the powertrain control module has detected either a short or too much resistance in the heater circuit. In Bank 1, the upstream heated oxygen sensor’s heater circuit is tested by this component.
The P0135 code occurs when the powertrain control module detects a short or excessive resistance in the heater circuit of the upstream heated oxygen sensor on Bank 1.
Code P0135 Definition: O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 1
The P0135 diagnostic trouble code (DTC) indicates a malfunction in the power supply for the O2 sensor heater circuit (Bank 1, Sensor 1).
Whenever you see the engine code P0315, it indicates that the powertrain control module performed the necessary tests on Bank 1’s upstream heated oxygen sensor. Alternatively, the heater circuit had a short or excessive resistance.
Common Symptoms Of The P0135 Engine Code
Depending on the engine code P0315, one or both of the following actions may occur:
- An increase in fuel consumption compared to usual.
- A service engine soon warning light is on (engine light on)
- As the exhaust heats up, the O2 sensor will start giving an output voltage, and the engine may run rough.
- It is also possible that your engine is running more roughly than usual.
- O2 sensor feedback will not be available to the ECM until the O2 sensor sends a signal.
What Can Cause The P0135 Engine Code?
A heated oxygen sensor aids the sensor in reaching operating temperature quickly, which is vital to an engine. To prevent an open-loop operation from taking too long, it minimizes the time it spends in it.
In an engine with the P0315 code, the heater circuit has been detected to have a short or excessive resistance.
The common causes behind the P0315 engine code include the following:
- The engine control module (ECM) is faulty
- There is a problem with the electrical connection of the heated oxygen sensor (H2OS) bank 1 circuit of sensor 1
- Bank 1 of the heated oxygen sensor (H2OS) has a shorted circuit to ground on sensor 1 of the bank.
- One heated oxygen sensor (H2OS) and one circuit fuse in each bank
- Bank 1 sensor 1 is faulty due to a faulty heated oxygen sensor (H2OS)
How Does A Mechanic Diagnose The P0135 Code?
- Measures the resistance of the O2 sensor heater circuit to ensure that it is within specifications
- Ensures that the heater circuit is receiving the correct voltage from the ECM by testing the O2 sensor connector
- Tests the heater circuit by monitoring the O2 sensor data
- Codes are scanned, and documents are frozen. Frame data is then cleared for failure verification
- Ensure that the bank 1 sensor 1 O2 sensor has the electrical connections and wire harness in good condition
Common Mistakes When Diagnosing The P0135 Code
- Leaving the O2 wire harness cover open without checking for water entry
- Oil or other contaminants are not checked on the O2 sensor
- Taking no steps to ensure the heater circuit is working after replacing the O2 sensor
- The replacement of parts before a thorough pinpoint test and visual inspection is conducted
Can I Fix The P0135 Engine Code Myself?
It is possible to fix this problem yourself if you are knowledgeable about advanced auto repair. The following may be necessary:
Make sure there is no corrosion or lose connections in the engine ground. It is necessary to remove any corrosion present and/or tighten the screws and restart the diagnostic procedure if either is present.
Ensure that no damage has been done to the electrical connections, wire harnesses, and metal tabs in terminals. Whenever you find any damage to the O2 sensor, you should replace it. That being said, here are some things you can try.
- Clear the code.
- Measure the voltage received by the O2 sensor with a multimeter.
- Using a multimeter, check the voltage of the O2 sensor. To check the fuse, if there’s no power, you should try to turn on the power.
- Make sure the car is turned off, and the harness connector is disconnected. Turn the ignition to ON but do not start the engine.
- You can confirm the issue by driving the car and checking whether the check engine light returns.
- The bank 1 sensor and 1 O2 sensor should be replaced if all these tests are positive.
How Serious Is The P0135 Engine Code?
There is no immediate need to address this DTC. In spite of that, it’s better to have it repaired or to have it checked out by your mechanic to prevent it from worsening. This could mean more expensive repairs in the future.
How Much Will It Cost To Fix?
There are a variety of ways to fix this issue, which determines the repair cost. In most cases, there are several options available. The following is how much they cost, including parts and labor:
- 100-1000 dollars for wiring repairs/replacements
- The fuse costs $5.
- An oxygen sensor costs $200-300
Can I Still Drive with a P0135 Code?
There are several inconveniences associated with a P0135 error code, such as poor fuel economy, engine stalling, and carbon buildup. Mechanical problems may not occur when driving short distances. The vehicle should, however, be repaired by a mechanic before being operated.
Heat is applied to the internal parts of the O2 sensor to enable it to provide feedback more quickly to the ECM. A heater failure may still cause the O2 sensor to give feedback to the ECM, but it will take longer than usual.