Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
The car's computer is having trouble understanding signals from a sensor that listens for unusual engine noises.
This code indicates a problem with the knock sensor circuit on bank 1, where the sensor's signals are not within the expected range.
The knock sensor detects vibrations caused by engine detonation and sends this information to the engine control module (ECM). Code P135B is triggered when the ECM detects that the signal from Knock Sensor 2 on Bank 1 is not within the expected range, indicating a potential issue with the sensor or its circuit.
• Check Engine Light is on
• Engine knocking noise
• Reduced engine performance
• Poor fuel economy
• Faulty knock sensor
• Wiring issues in the knock sensor circuit
• Poor electrical connection
• ECM malfunction
ECM: Engine Control Module
Knock Sensor: A sensor that detects engine knocking or pinging.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage or corrosion.
• Test the knock sensor for proper operation.
• Check the ECM for any faults.
• Replace the faulty knock sensor.
• Repair or replace damaged wiring or connectors.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Socket set
$150 - $400
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly inspect engine wiring.
• Keep engine components clean.
• Use quality fuel to prevent knocking.
Sensor Issue
• Avoid hard acceleration until the issue is fixed.
• Have the vehicle inspected by a professional mechanic.
Check with the vehicle manufacturer for sensor-related warranty coverage.
This code has been reported in various models, often due to sensor wear or wiring issues.
Moderate – It should be addressed soon to prevent engine damage.
Ignoring this issue can lead to increased emissions and potential engine damage.
• Engine at operating temperature
• Vehicle in a controlled environment
The knock sensor is typically located on the engine block, cylinder head, or intake manifold.
Q: Can I drive with a P135B code?
A: It's not recommended as it can lead to engine damage.
Q: How long does it take to fix a P135B code?
A: Repairs can take a few hours depending on the exact cause.
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